Efficiency enhancement of dye-sensitized solar cells (DSSCs) using a gel polymer electrolyte added with tert-butyl pyridine.

Efficiency enhancement of dye-sensitized solar cells (DSSCs) using a gel polymer electrolyte added with tert-butyl pyridine. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Efficiency enhancement of dye-sensitized solar cells (DSSCs) using a gel polymer electrolyte added with tert-butyl pyridine. Sohibjon Boqiyev, Abdulaziz Abdukarimov, Shah Shahan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8534346/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Phthaloyl-chitosan (PhCh) blended with polyethene oxide (PEO) forms the host in a gel polymer electrolyte with a composition of 5.04 wt.% PhCh-1.26wt.% PEO-31.51wt.% DMF-37.81 wt.% EC-24.38wt.% TPAI(+ I 2 ). To this composition X wt. % of tert-butyl pyridine (TBP) [X = 0, 2, 4, 6, 8] has been added. The conductivity of the electrolytes has been calculated from impedance data obtained using electrochemical impedance spectroscopy (EIS)—the GPEs with different wt. % TBP exhibits a conductivity of 9 mS cm − 1 , which is slightly lower than the GPE without TBP being 11 mS cm − 1 at room temperature. Dye-sensitized solar cells (DSSCs) have been assembled with a ruthenium-based dye as sensitizer. The photocurrent density-voltage ( J-V ) characteristics of the DSSCs have been measured under white-light illumination of 1000 W m-2, with an active area of 0.20 cm 2 . The electrolytes containing 8 wt.% TBP exhibit the highest efficiency of 8.74% with J sc = 17.23 mA cm − 2 , V oc = 0.72 V and FF 0.70. The incident photon to current conversion efficiency (IPCE) for DSSC was characterised using the Newport Model 70528 Oriel Monochromator Illuminator—the DSSC with eight wt. % TBP shows the highest quantum efficiency of 72.9% at 530 nm. Ruthenium dye DSSCs IPCE TBP gel polymer electrolytes Conductivity Figures Figure 1 Figure 2 Figure 3 1. Introduction Since the report of O’Regan and Gratzel [ 1 ], there has been increasing research on dye-sensitized solar cells (DSSCs). DSSCs have been considered an alternative to conventional silicon-based solar cells because they are easier to fabricate and have lower production costs. DSSC efficiency has achieved 12.3% using porphyrin dyes and a cobalt-complex redox mediator [ 2 ]. DSSCs consist of a dye-adsorbed TiO 2 electrode, a Pt-coated counter electrode, and an electrolyte with a redox mediator between them. Under illumination, the photo-excited dye injects electrons into the conduction band of TiO 2 . The injected electrons are then collected at the photoanode and transferred to the counter electrode. The redox couple regenerates the oxidized dyes in the electrolyte. However, some limitations restrict the commercialization of DSSCs, such as (i) low photo-conversion efficiency, (ii) long-term instability and (iii) no proven low manufacturing cost process. Among these problems, the long-term instability is the major drawback for the commercialisation of DSSCs. It is generally attributed to the evaporation and leakage of liquid electrolyte if the cell is not adequately sealed [3]. In another, much more straightforward approach, optimisation of the electrolyte would also increase device efficiency [4–6], but stability must still be addressed for commercialisation. The most convenient way to enhance the photovoltaic Efficiency is the addition of appropriate chemical species in the electrolyte to fine-tune the semiconductor electrolyte interface. For instance, nitrogen heterocyclic compounds such as 4-tert-butylpyridine (TBP) can be added to the electrolyte to improve the open-circuit potential (V oc ) [7, 8]. TBP remarkably improves the photo-voltage of the solar cell, and the improvement is attributable to suppression of the dark current [ 9 ]. We have focused on the electrolyte compositions, particularly the concentration of [TBP]. Our results indicate that these additives play an essential role in improving the open-circuit potential (V oc ) and the solar cell performance. It can be adsorbed onto incompletely coordinated Ti atoms at the surface of the TiO2 electrode [10]. TBP deprotonates the TiO2 surface by adsorption, thereby shifting the conduction band edge of TiO2 (Ec) towards more negative potentials and passivating the surface, thereby reducing active recombination sites [11–12]. In addition, it increases the electron lifetime by preventing the electron recombination with the triiodide ion the electrolyte [ 13 ]. 2. Experimental 2.1 Materials Tetra propyl ammonium iodide (TPAI), polyethene oxide (PEO), Tert-butyl pyridine (TBP) and ethylene carbonate (EC) were purchased from Sigma-Aldrich. Dimethylformamide (DMF) was purchased from Friedemann Schmidt Chemical. Iodine (I 2 ) crystals were purchased from Amco-chemie-Humburg. Phthaloyl-chitosan was synthesized by the reaction of chitosan with phthalic anhydride, which was purchased from Merck (Germany). TiO 2 particles of sizes 15 nm (P90) and 21 nm (P25) were purchased from Evonik Industries. Polyethylene glycol with molecular weight 200 (PEG-200) was purchased from Merck (Germany), and absolute ethanol was purchased from John Kollin Corporation. 2.2 Electrical conductivity measurement The ionic conductivity of the phthaloyl chitosan-TPAI-based biopolymer electrolyte films was measured using the Hioki 3531 Z Hi Tester over the frequency range from 50 Hz to 5 MHz. To this composition, X wt. % of tert-butyl pyridine (TBP) (X = 2, 4, 6, 8) has been added to stabilise ionic conductivity and solar cell efficiency. 2.3 Preparation of TiO 2 electrodes and counter electrode Two-layer TiO2 electrodes were used in the DSSCs, with the porous TiO2 layer soaked in dye serving as the sensitiser. The first TiO 2 layer was prepared by adding 0.5 g of TiO2 (P90) powder to 2 mL of 0.1 mol nitric acid and grinding for 30 minutes to serve as a barrier to prevent electron recombination. The paste was spin-coated on fluorine-doped tin oxide (FTO) glass and then sintered at 4500°C for 30 minutes. The second TiO 2 layer was prepared by grinding 0.5 g TiO 2 (P25) powder with 2 mL of 0.1 mol nitric acid and 0.1 g Triton-X(100) carbowax for 60 minutes, and then two drops of surfactant were added to get a homogeneous paste. The TiO 2 paste was then coated on top of the first compact layer using the doctor blade method, and the resulting composite was sintered at 450°C for 30 minutes. Sintering removes the Triton-X(100) component and results in the second TiO 2 layer being porous. The counter electrode was prepared using Platisol (Solaronix), spin-coated onto fluorine-doped tin oxide (FTO) glass, and then sintered at 450°C for 30 minutes. 2.4 Preparation of dye sensitizers The N3 dye concentration was prepared by adding 2.2 mg of the ruthenium-based dye to 10 ml of ethanol. The prepared photoanode was soaked in the dark at room temperature for 24 hours. 2.5 Cell assembly and characterization An optimised phthaloylchitosan (PhCh) based gel polymer electrolyte (GPE) having the composition 5.04 wt.% PhCh-1.26wt.% PEO-31.51wt.% DMF-37.81 wt.% EC-24.38wt.% TPAI(+ I 2 ) was used to fabricate DSSCs with the configuration FTO/TiO 2 -dye/GPE/Pt/FTO. The electrolyte containing the I − /I 3 − redox couple was sandwiched between the photoanode and platinum (Pt) counter electrode. The photocurrent density-voltage ( J-V ) characteristics of the DSSCs were measured using a Keithley 2400 source meter under white-light illumination of 1000 W m − 2 . The active area of the solar cell is 0.20 cm 2 . The fill factor ( FF ) was calculated using the equation: J max and V max are the maximum current density and maximum voltage, respectively at the maximum power output density. J sc and V oc are the short-circuit current density and open-circuit voltage, respectively. The light-to-current conversion efficiency ( η ) was calculated using the following equation: (2) where P in is the input light energy. 2.6 Incident photon to current conversion efficiency (IPCE) for DSSCs The IPCE measurements were taken using a Newport Model 70528 Oriel Monochromator Illuminator. The IPCE spectrum is a plot of the ratio of the number of output electrons (current) to the input photons (irradiance) as a function of wavelength. The incident-photon-to-current conversion efficiency indicates the current the cell will produce when irradiated with photons of a particular wavelength. 3. Results and discussion 3.1 Electrical conductivity The conductivity of the electrolytes has been calculated from impedance data obtained by electrochemical impedance spectroscopy (EIS). Room-temperature electrical conductivity data for composite phthaloyl chitosan-TPAI with additives, using a tert-butyl pyridine electrolyte system, are reported. The conductivity at room temperature of 0 wt.% of 1.1 x 10 − 2 (S/cm), 2 wt.% of 9.0 x 10 − 3 (S/cm), 4 wt.% of 8.6 x 10 − 3 (S/cm) ,6 wt.% of 1.0 x 10 − 2 (S/cm) and 8 wt.% of 9.0 x 10 − 3 (S/cm), Table 1 Composition of gel polymer electrolytes with additives, tert-butyl pyridine (TBP) Wt % PEO PhCh DMF EC TPAI I 2 TBP 2 wt% 1.24 4.94 30.88 37.05 22.23 1.67 1.99 4 wt% 1.21 4.84 30.24 36.3 21.78 1.63 4.00 6 wt % 1.18 4.74 29.61 35.53 21.32 1.60 6.00 8 wt % 1.16 4.64 28.98 34.78 20.87 1.57 8.00 To measure ionic conductivity, we have sandwiched free-standing biopolymer electrolyte films between steel electrodes. The electrical conductivity was evaluated using the formula σ = R b (l/A), where σ = l / (R b · A) σ is the ionic conductivity, R b is the bulk resistance, l = 0.285 cm is the thickness of the sample, and A = 2.2707 cm 2 is the area of the given sample. 3.2. J-V Characteristics of DSSCs Figure 2 shows the J–V curves of the DSSCs fabricated with different TBP contents in the polymer electrolytes. The corresponding performance parameters are summarised in Table 2. It can be observed that the DSSC with 8 wt% TBP exhibits a higher current density of 17.23 mA cm-2 and a higher efficiency of 8.74% compared to the other DSSCs.On the other hand, without additives added in the polymer electrolyte, the solar cell efficiency exhibited was 7.10%, with a V oc of 0.65 V. The V oc and FF values increased with the addition of TBP and as the TBP concentration increased. The Jsc value decreased slightly with increasing TBP concentration but remains above 16 mA cm − 2 . Consequently, the total conversion efficiency increased remarkably from 7.10% for 0 wt % of TBP to 8.74% for eight wt % of TBP (Table 2). Considering these results, the Fermi level of TiO2 may have shifted to a more negative potential due to TBP adsorption on the TiO2 surface, resulting in a significant difference between the Fermi level and the redox potential, thereby improving V oc [ 14 ]. At a more negative potential, charge recombination between injected electrons in TiO2 and the cations of a Ru complex (N3 dye) is reported to be relatively slow [ 15 ]. Taking this point into consideration, recombination between injected electrons and triiodide ions under irradiation may reduce photocurrent. However, it may be implied that the recombination rate is slow since the J sc is still, on average, greater than 16 mA cm − 2 . Thus, although the Fermi potential has shifted to a more negative value, the reduced electron leakage has left Jsc almost unchanged. As shown in Fig. 2 , the addition of TBP (і) has nearly relinquished electron recombination and prevented a significant decrease in photocurrent at relatively low voltage and (іі) led to an increase in V oc by increasing the Performance parameters of DSSCs Table 2 Wt %TBP σ(Scm − 1 ,At RT) J sc (mA/cm 2 ) V oc (V) Fill Factor (FF) η (%) 0% TBP 0.011082 16.56 0.65 0.66 7.10 2% TBP 0.009017 16.40 0.66 0.71 7.68 4% TBP 0.008571 16.3 0.68 0.70 7.76 6% TBP 0.010026 16.23 0.70 0.71 8.06 8% TBP 0.008976 17.23 0.72 0.70 8.74 difference in potential between the Fermi level and redox level, and (ііі) increasing FF values. The effect of TBP on the surface would be similar to that of metal oxide blocking layers, which inhibit recombination between injected electrons and triiodide ions and consequently improve the V oc of the solar cells, as reported by several groups [ 16 ]. The current density obtained for 8 wt % of TBP is higher compared to the others. The fill factor and voltage also increased in the polymer electrolyte system with additives compared to those without a TBP electrolyte. The higher dye adsorbed also leads to increased light absorption in the photo-electrode, and thus gives rise to higher J sc . 3.3 Incident photon to current conversion efficiency (IPCE ) Figure 3 shows the IPCE spectrum for DSSCs with and without additives. The dye sensitized solar cells can efficiently convert visible light to photocurrent from 300 nm to around 750 nm. As can be seen in Fig. 3 , the IPCE value reached is 72.9% at 530 nm for the cell with 8 wt% of TBP electrode. [He et al.] reported that TBP as co-adsorbates improved the IPCE performance of DSSCs based on zinc phthalocyanine photosensitizers [ 17 ]. They suggested that reduced surface aggregation due to the coadsorbates, which suppresses quenching processes due to energy transfer or charge transfer reactions between the aggregated molecules and/ or between molecules in the aggregates and monomers, leads to the improved IPCE performance. In addition, [Khazraji et al.] reported that the IPCE performance of a merocyanine dye-sensitized TiO2 solar cell is enhanced by the addition of a co-adsorbate, which prevents the formation of a dimer whose electron-injection performance is lower than that of the monomer [ 18 ]. Higher IPCE values indicate that the electron transfer process from excited dye molecules to the conduction band of semiconductors occurs effectively [ 19 ]. This indicates that the dye adsorption on the semiconductor surface is better in the 8 wt % of TBP. As can be seen from Fig. 3 , the IPCE of the DSSC with photoanode 0 wt% of TBP,2 wt% of TBP, 4 wt% of TBP,6 wt% of TBP and 8 wt% of TBP reached a maximum value of 61.5%,66.0%, 66.82%, 69.0% and 72.9% at 530 nm. Although the current density is approximately the same, the voltages differ due to the additives. From Fig. 3 , we can also observe that the IPCE value for the photoanode with 0 wt% TBP electrolyte is maximum at 530 nm, at 61.5%. After adding additives, the IPCE increased significantly over the long-wavelength range (300-800nm). The broader IPCE spectrum suggests improved interaction between dye molecules and the semiconductor substrate. These interactions lead to changes in the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the dye adsorbed on the semiconductor surface, resulting in the broadening of the action spectrum of IPCE [ 20 ]. Conclusion Dye-sensitized solar cells containing phthaloylchitosan gel polymer electrolyte-based DSSCs were fabricated. The 8 wt.% TBP blend shows the best Voc and ff values for a DSSC based on a ruthenium dye, which were remarkably improved by the addition of TBP. In contrast, the Jsc values decreased slightly with increasing TBP, except at the 8 wt.% TBP composition. Consequently, the total conversion efficiency increased remarkably from 7.68% to 8.74%. compared to all other films. The improved Voc was probably due to the suppression of recombination between electrons and I 3 - ions (dark current). Declarations Author Contribution Boqiyev Sohibjon performed the experiments, analyzed the data, and wrote the first draft. Abdukarimov Abdulaziz supervised the study and revised the manuscript. Shahan Shah contributed to materials preparation and data interpretation. All authors reviewed and approved the final manuscript. 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07:58:55","extension":"xml","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":53976,"visible":true,"origin":"","legend":"","description":"","filename":"72d401f0c2214cd7b151c642d3dd01811structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/87f310b938c74c1ccae8482d.xml"},{"id":100369720,"identity":"889d241a-3c13-4530-b14c-9c05c87143a5","added_by":"auto","created_at":"2026-01-16 07:59:21","extension":"html","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":63889,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/ec70c8a00c1d6e2a4ed4759d.html"},{"id":100201044,"identity":"63da7cf2-cf05-4206-9bd2-c1a7108a5f82","added_by":"auto","created_at":"2026-01-14 04:59:31","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":76100,"visible":true,"origin":"","legend":"\u003cp\u003eConductivity plot of different wt. % of TBP electrolytes.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/27264e58ee9133d5d5effabf.jpg"},{"id":100370148,"identity":"d1eddf7c-1503-47df-8657-8b6511653f06","added_by":"auto","created_at":"2026-01-16 08:00:08","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":62433,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eJ-V\u003c/em\u003ecurves of DSSCs with and without TBP.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/3aff828119d77f54e7bba019.jpg"},{"id":100201048,"identity":"d73ea178-a6c3-4dcf-ac66-9f8fa5eb5e4b","added_by":"auto","created_at":"2026-01-14 04:59:32","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":75138,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eIPCE \u003c/em\u003ecurves of DSSCs with photo-electrodes\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/f68dbfa84c0022d7fe15d553.jpg"},{"id":101108692,"identity":"02957531-ba85-407c-b874-7f5039ed0d73","added_by":"auto","created_at":"2026-01-26 05:09:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":798565,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8534346/v1/510a2e77-5552-4469-b777-2c875225c9be.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEfficiency enhancement of dye-sensitized solar cells (DSSCs) using a gel polymer electrolyte added with tert-butyl pyridine.\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSince the report of O\u0026rsquo;Regan and Gratzel [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], there has been increasing research on dye-sensitized solar cells (DSSCs). DSSCs have been considered an alternative to conventional silicon-based solar cells because they are easier to fabricate and have lower production costs. DSSC efficiency has achieved 12.3% using porphyrin dyes and a cobalt-complex redox mediator [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. DSSCs consist of a dye-adsorbed TiO\u003csub\u003e2\u003c/sub\u003e electrode, a Pt-coated counter electrode, and an electrolyte with a redox mediator between them. Under illumination, the photo-excited dye injects electrons into the conduction band of TiO\u003csub\u003e2\u003c/sub\u003e. The injected electrons are then collected at the photoanode and transferred to the counter electrode. The redox couple regenerates the oxidized dyes in the electrolyte. However, some limitations restrict the commercialization of DSSCs, such as (i) low photo-conversion efficiency, (ii) long-term instability and (iii) no proven low manufacturing cost process. Among these problems, the long-term instability is the major drawback for the commercialisation of DSSCs. It is generally attributed to the evaporation and leakage of liquid electrolyte if the cell is not adequately sealed [3]. In another, much more straightforward approach, optimisation of the electrolyte would also increase device efficiency [4\u0026ndash;6], but stability must still be addressed for commercialisation.\u003c/p\u003e \u003cp\u003eThe most convenient way to enhance the photovoltaic\u003c/p\u003e \u003cp\u003eEfficiency is the addition of appropriate chemical species in the electrolyte to fine-tune the semiconductor electrolyte interface. For instance, nitrogen heterocyclic compounds such as 4-tert-butylpyridine (TBP) can be added to the electrolyte to improve the open-circuit potential (V\u003csub\u003eoc\u003c/sub\u003e) [7, 8]. TBP remarkably improves the photo-voltage of the solar cell, and the improvement is attributable to suppression of the dark current [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. We have focused on the electrolyte compositions, particularly the concentration of [TBP]. Our results indicate that these additives play an essential role in improving the open-circuit potential (V\u003csub\u003eoc\u003c/sub\u003e) and the solar cell performance. It can be adsorbed onto incompletely coordinated Ti atoms at the surface of the TiO2 electrode [10]. TBP deprotonates the TiO2 surface by adsorption, thereby shifting the conduction band edge of TiO2 (Ec) towards more negative potentials and passivating the surface, thereby reducing active recombination sites [11\u0026ndash;12]. In addition, it increases the electron lifetime by preventing the electron recombination with the triiodide ion the electrolyte [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eTetra propyl ammonium iodide (TPAI), polyethene oxide (PEO), Tert-butyl pyridine (TBP) and ethylene carbonate (EC) were purchased from Sigma-Aldrich. Dimethylformamide (DMF) was purchased from Friedemann Schmidt Chemical. Iodine (I\u003csub\u003e2\u003c/sub\u003e) crystals were purchased from Amco-chemie-Humburg. Phthaloyl-chitosan was synthesized by the reaction of chitosan with phthalic anhydride, which was purchased from Merck (Germany). TiO\u003csub\u003e2\u003c/sub\u003e particles of sizes 15 nm (P90) and 21 nm (P25) were purchased from Evonik Industries. Polyethylene glycol with molecular weight 200 (PEG-200) was purchased from Merck (Germany), and absolute ethanol was purchased from John Kollin Corporation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Electrical conductivity measurement\u003c/h2\u003e \u003cp\u003eThe ionic conductivity of the phthaloyl chitosan-TPAI-based biopolymer electrolyte films was measured using the Hioki 3531 Z Hi Tester over the frequency range from 50 Hz to 5 MHz. To this composition, X wt. % of tert-butyl pyridine (TBP) (X\u0026thinsp;=\u0026thinsp;2, 4, 6, 8) has been added to stabilise ionic conductivity and solar cell efficiency.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Preparation of TiO\u003csub\u003e2\u003c/sub\u003e electrodes and counter electrode\u003c/h2\u003e \u003cp\u003eTwo-layer TiO2 electrodes were used in the DSSCs, with the porous TiO2 layer soaked in dye serving as the sensitiser. The first TiO\u003csub\u003e2\u003c/sub\u003e layer was prepared by adding 0.5 g of TiO2 (P90) powder to 2 mL of 0.1 mol nitric acid and grinding for 30 minutes to serve as a barrier to prevent electron recombination. The paste was spin-coated on fluorine-doped tin oxide (FTO) glass and then sintered at 4500\u0026deg;C for 30 minutes. The second TiO\u003csub\u003e2\u003c/sub\u003elayer was prepared by grinding 0.5 g TiO\u003csub\u003e2\u003c/sub\u003e (P25) powder with 2 mL of 0.1 mol nitric acid and 0.1 g Triton-X(100) carbowax for 60 minutes, and then two drops of surfactant were added to get a homogeneous paste. The TiO\u003csub\u003e2\u003c/sub\u003e paste was then coated on top of the first compact layer using the doctor blade method, and the resulting composite was sintered at 450\u0026deg;C for 30 minutes. Sintering removes the Triton-X(100) component and results in the second TiO\u003csub\u003e2\u003c/sub\u003e layer being porous. The counter electrode was prepared using Platisol (Solaronix), spin-coated onto fluorine-doped tin oxide (FTO) glass, and then sintered at 450\u0026deg;C for 30 minutes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Preparation of dye sensitizers\u003c/h2\u003e \u003cp\u003eThe N3 dye concentration was prepared by adding 2.2 mg of the ruthenium-based dye to 10 ml of ethanol. The prepared photoanode was soaked in the dark at room temperature for 24 hours.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Cell assembly and characterization\u003c/h2\u003e \u003cp\u003eAn optimised phthaloylchitosan (PhCh) based gel polymer electrolyte (GPE) having the composition 5.04 wt.% PhCh-1.26wt.% PEO-31.51wt.% DMF-37.81 wt.% EC-24.38wt.% TPAI(+\u0026thinsp;I\u003csub\u003e2\u003c/sub\u003e) was used to fabricate DSSCs with the configuration FTO/TiO\u003csub\u003e2\u003c/sub\u003e-dye/GPE/Pt/FTO. The electrolyte containing the I\u003csup\u003e\u0026minus;\u003c/sup\u003e/I\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e redox couple was sandwiched between the photoanode and platinum (Pt) counter electrode. The photocurrent density-voltage (\u003cem\u003eJ-V\u003c/em\u003e) characteristics of the DSSCs were measured using a Keithley 2400 source meter under white-light illumination of 1000 W m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. The active area of the solar cell is 0.20 cm\u003csup\u003e2\u003c/sup\u003e. The fill factor (\u003cem\u003eFF\u003c/em\u003e) was calculated using the equation:\u003c/p\u003e \n\u003cp\u003e\u003cimg 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pc/WdHZ2Cv3eiYgof1zKKTE9PT348ccfEYvFAAA//fQT9uzZI+wH++TkJGpra41QoqoqhoeHUVNTI/x7JyKi/DGYlBhJktDd3Y2rV68Ci6ew1tTUmLsJY2ZmJut4/d9//x0PHz7E9u3bhX/vRESUPwaTEqHfUqwoCpLJJP7++2+oqoq6ujpcv34dqqpiaGgIly9fNg/dcNPT01BVFbFYDIcOHcLXX38Nm81WEO+diIjyw2BSItLpNH799Ve88MILOHToEA4ePAhJktDZ2Yl4PI6ysjLE43HhNo4ePXoUzzzzDMrKynD06FHcvn3b2B8j+nsnIqL8cfMrERERCYMzJkRERCQMBhMiIiISBoMJERERCYPBhIiIiITBYEJERETCYDAhIiIiYTCYEBERkTAYTIiIiEgYDCZEREQkDAYTIiIiEgaDCREREQnj/yWpLPciB8PIAAAAAElFTkSuQmCC\" width=\"550\" height=\"93\"\u003e\u003c/p\u003e\n\u003cp\u003e \u003cem\u003eJ\u003c/em\u003e \u003csub\u003emax\u003c/sub\u003e and \u003cem\u003eV\u003c/em\u003e\u003csub\u003emax\u003c/sub\u003e are the maximum current density and maximum voltage, respectively at the maximum power output density. \u003cem\u003eJ\u003c/em\u003e\u003csub\u003esc\u003c/sub\u003e and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eoc\u003c/sub\u003e are the short-circuit current density and open-circuit voltage, respectively. The light-to-current conversion efficiency (\u003cem\u003eη\u003c/em\u003e) was calculated using the following equation:\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAYoAAABJCAYAAAAjdWG+AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAAFiUAABYlAUlSJPAAAA9XSURBVHhe7d1BTBTXHwfwLz016WjTDAdxvYBBQw9WYiBpUtuU1aQIRg5VkNTBxto25VBk29SejDetbKQH0lBNWttG0L1gWKRJhWj0pIG1XAiQQtK4zCaFg5l3aE/vf9k3/93Z2WWX2V1m9ftJ5jLvzTor+/a3897vvVclpZQgIiLK4hXnCSIiolQMFERElBMDBRER5cRAQUREOTFQEBFRTgwURESUEwMFERHlxEDhA0IIHDp0CFVVVRlHOBy264XD4YzyaDSa9lqVKBqNZryvqqoq9PT0OKv6jmma2L17d8a95zrU38zLtURlJck3Zmdnpa7rEoDs7++XlmU5q8iRkREJQAaDQbm4uOgsrliWZclgMFix7039XXRdl7Ozs85iubi4KIPBoKyrq5Orq6tpZV6uJSoHPlH4SH19Pfbv3w9d1/HRRx9B0zRnFcTjcRiGgbGxMdTX1zuLK5amaQgEAgCAvr6+intv6m+1f/9+13uvr6/HlStX0NHRgZqamrQyL9cSlQMDhY9YloWVlRW8/vrr2LFjh7MY0WgUk5OTGBoacg0ilcw0TTx69Ah1dXU4cOCAs9j3FhYWAACtra05/zbHjh1znvJ0LVE5MFBUiFgshlAohCtXruT8MqlUMzMzWF5exjvvvFNxv5qFEJicnISu62hpaUkru337NmKxGACgsbER7777blq5l2uJyoWBwkcSiQSeP3+O2tpabNu2zT4vhMClS5cQDofR2NiYdk05jI6OIhQKOU+nCYVCGB0ddZ7OWyQSAQAcP37cWVR0xX4/S0tLePr0aUbXkWmauHfvnmt3kuLlWqJyYaDwkXg8jvX1dQQCgbSnhuHhYbz66qtob29Pq18u7733Hh4+fIienh4IIdLKhBDo6enB2NjYpruMyt3tVOz3Mz09jfX19bSuo6WlJZw6dQr//fdfzidAL9cSlY1zdJu2zsDAgAQgBwYG7HPj4+PyxIkTrhlQ5bS6uiqbmpqkYRj2vViWJQ3DkE1NTZ6yccbHxyUAaRiGs6hkivV+UrO13I7x8XHnJTYv1xKVE58ofMw0TQwNDeH8+fNb/suypqYG09PTiMfj6OjoQCKRQEdHB+bn53Hnzh1P4wqq22nfvn3OopIp1vtRXUfBYBCWZUFKCSklZmdnsWfPHjuTy42Xa4nKiYHCR+bm5gAAe/fuhRACfX196O3t3ZJxCTeapmFsbAxIftEi2XWS75eqG9Xt5DaYW2rFeD9uXUdIDj53d3e7Zq8pXq4lKicGCp8QQiAej0PXdQQCAQwPD2PXrl1bNi5RLirbyTmYWwlUxhKSwd1ZtmvXrqxBx8u1ROXGQOETqXMoTNPE48ePcfHiRWe1LSWEQEdHB5B8EgCAjo6OjAHhQqhuJ+ev6nLw+n5U15HbILymaThz5kzauVReriUqNwYKn1leXsa5c+d8MS6RyjRNu2tobGwMO3bswNjYGAKBAFpaWuwvWjexWAzV1dUZKamxWAwTExOoq6tDd3d3WlmpeXk/iuo62szcDy/XEpUbA4VPqDkUSC7+55dxCSS/VI8dO4aGhgaMjY3ZAUzTNAwNDaGhoQHHjh3L+uU6ODiI9fV1rK2t2eeEEPj666+xvr6OL774oqxfll7fDxxdR4XO/fByLdFWYKDwCTWHwjAM341LPHjwAAcPHsSNGzcynnI0TcONGzdw8OBBPHjwIK1M2bdvH3Rdt78UY7EYWlpaMDU1hYGBgYwnjVLz+n6QnLQ3NTVljykVwsu1RFvCmS9LW2NgYEAGg8GSzJeYmJiQTU1NEslVaVONjIxIXdelrusly9u3LEv29/fb8wN0XZdnz57Na4XYa9eu2Svqps4vKcd9u1FzPpxHPn87L9cSbaUqKaV0Bg96cUSjUXz55Zf4/fffUVNTg97eXhw/fhzt7e0Ih8OYnJzEDz/8gIWFBSQSCXzyySfOl9gyQgicOXMG58+fT+uK8/t9E71oGCheYKovfnh42P6iVRshdXd3wzAM/PLLL2UdHyhUKBTC+++/b3fHmaZZEfdN9CKpiDEKIQSuXr2K69evO4s8u379Oq5evZp3SmQlmZmZQUNDgx0k1CDq3r17cfPmTXzwwQe+/7K9ePEifv31V3sV1Uq5b6IXie8DhUpjfPbsGbq6uuzzo6OjqK6uRlVVFZqbm+0vkmyEEOjs7Myo19XVhWfPnhWUP18pFhYW0pbFuH//PlZWVnDgwAHMzc1lTPTyI03TcP78efz2229AcvZ6Jdx3pUkkErh9+za6urpQXV2d0U6chBD49NNP7S1aQ6FQzvZTSP1itW0qHl8HCtV10tnZiXA4bGeoRKNRnDx5Et9++y0sy8L27dvx4Ycf5kxnvHDhAk6dOpWRdqppGsLhMFpbW/POn68kc3NzEEIgFovh9OnT+P7771FTU4N9+/YhEolACIG7d++W5GnNC5U+a5om4vE4nj17BiGE7++7EsViMXz88cf46aefcOvWLWdxBtM08dZbb2F5eRmWZcGyLPz5559Zf2wVUr+YbZuKyDm67SeGYWSsKKpW3EzdP1hlk6RmxaQaHx/PyPZx4/bvVTLLsuTZs2clANnU1JS2H7NaPTXX/9tWWl1dlXV1dVJlSanMJr/fdyVT/+fZ9u5WDMPIqKP2e3drP/nWL2XbJm98GyjGx8czPlwy5QOWmlLodk5ZXV2VnZ2deS0brV6nnOmWRH6hvqjd2p3i9gUvc1xbSH23dux2TimkbZM3vux6EkJgcHAQbW1tnh4nRXIF1m+++Savwc/6+nrs378fg4ODGY/ERPT/WfbOJeE1TUMgEMD6+jqmp6c3XT9fhbZt8qbkgSIWi6G5udkemFpaWoJIZjFlG7C6f/8+pqamMj5chRoeHkZzc3PewUbTNLS2tmJqagr37993FhP5VrG3d3Ujkiscw2XFW6TsJ6KWyy+0fiEKbdvkTUkDRSwWg2mamJ6eRjAYxPLyMn788UeEw2GcPHkSa2trGBgYwJMnTzA4OGhfp1YUdftwqV/9KysrsCwLyLKFaCwWw+rq6oaNx0n9m+oeiCpBsbd3daNWOM5GtZ14PA4hRMH1S922afNKGigaGxtx5MiRtA9Md3c3Lly4YG/Koj4s6teF+hWSbR0cTdPQ19eH5eVl3Lx50+6m0nUdfX19QDLL4vLly/jqq6+A5GuGQiFUVVWhuroaFy9ezGhMSiAQgK7r9ofXTTgcttP88jnUJDeiUqmpqcGdO3cwPz+P3t5e+7MrhEBvby/m5+fx6NGjsuz5kfpFnw9Vv9RtmzxwDlqUQq7MBcMwJFL2B1aZF6mZD27UWj9uGT39/f1pA9KpWRfZBteUfP99Ij9Sg8TBYFCapimDwWDee4C7DTCnSs1Ec0v4UO1ctZ1C6yulatu0eSV9olAikYjrVpdmchtMt81bNtLV1YW1tTVIKfH48eO0JSp27txpL/mg9jxQA+ONjY1oa2vDxMQEJ+jQC0crwvaum7WwsAAAqK2txbZt25zFGbLVZ9v2n5IHChUM3La6VNtgFmvzllgshsePH+Ozzz6zz6kNYpwD45vNtig2ZzcVDx4bHVtl27ZtqK2tdZ7OoMYTCq2fSyW27RdJyQOFCgZuW12qAeNibN4ihMClS5fy2hnO+cHaSsm5LDx45H3kIjxu75qLSmlFytNAKpW9pNpXofWzqdS2/SIpeaAotNtJ/Qp5/vw5EolE2jW5FDKNP1c6ntppzvk4nIqD2eRHal00eNjedSPqR52zDaUmoaS29ULruylW26bNK2mgUH2IhXQ7pU7EUTnYG4lGowDgujNcS0sLdF3PyO3O9gF1S8dzCoVCGb/ych1M46NSU+uiedneNR/t7e0wDAOPHj1Ke62lpSU8ffo0Y5JsofWditm2keyW+u6773D37l1nEcDy7Jyj28U0MDCQd7ZTqlxZUk75TOMvJDNC3bPbfRH51cjIyIZrHvX398uRkRHnadvs7KydpXTt2jVnsU1lMxmGIS3LkouLizmzqwqtrxS7bUsp5eXLlyWSOwu6ednLsymsdgFypdptlIKamuLnXN8llWVZ8sSJExmv72Q5tuLs7+/P+rqGYWz47xK9SFR7U+1DHW5tV1lcXJQnTpyw6+VqU3IT9UvRtqWU8uHDh/KNN96QnZ2dziIpWZ7VluxwF41GcfToURiGgRs3bjiLgWSd06dP448//sj5aFpMsVgMhw8fxs8//+z6qEtE9DIq6RhFNvlkO7W3t6OtrS1taY9SUwsRMkgQEf1f2QNFtmwnN0NDQ4jH42XJGgqHw5ifn8elS5ecRUREL7WyB4ps2U5u1CzTycnJnFsneqHWirl16xbu3Lmz4T1R4UzTxO7duzPShlOP1tZWLC0tOS8lIh8oe6BQE2/ynRijaRru3buHhoYGT0skZzM6Oopdu3aVbZmDl1FNTQ3++usvjIyMAAB0XceDBw/s9OGJiQk8efIEb7/9NpdeIPKhLRnMppeTSmIIBoNpuf4blRHR1ir7EwW9vNTTpNtkRrW8e6FLVBNR6TFQUFkIITA5OQlkyXZTM+KJyH8YKKgs1JIN2bLdVMp0PkkORFReDBRUFmpJaLdAoNYES93JjIj8g4GCSi612yk1200IgatXr+Lw4cMAUNZZ+ESUP2Y9UcmppVEAoKmpCU+ePLHHI/bs2YPPP/8cZ8+ezRjgJiJ/4BMFlZzqdmpra8Pk5KS9zaWUEgsLCzh37hyDBJGPMVBQyan9AtyynYjI/xgoqKQKWduLiPyJgYJKqpC1vYjInxgoqGSEEPYy8cXqdopGozh06FBJFogkIncMFFQy0WgUU1NT0HXdWbRp7e3tuHfvHge/icqIgYKKLhqNoqqqCidPngSSG7ofPXoUu3fvhmmazup5U6/b09NjL12uXnN0dBTV1dVl2buE6GXDeRRUUXp6enD8+HG0t7fDNE1cuHABLS0tQHJJ+kgkknV7XSLaHD5RUMUwTROrq6t29tTMzAy2b9+OV155BV1dXYhEInnvc0JE+WOgoIoxMzODnTt32tlTkUgE//zzD44cOQIhBP7991/76YKIioeBgipGJBKxs6dM08T8/Dz6+vqgaZq9jWp9fb3jKiLyioGCKoLqdgoEAhBCIJFIoLa21g4M09PTePPNN5FIJJyXEpFHDBRUERKJBP7++2+YpglN0zA9PY3m5mY7TXZubg7xeByvvfaa81Ii8ohZT0RElBOfKIiIKCcGCiIiyomBgoiIcmKgICKinP4H/kuOvuX7jWEAAAAASUVORK5CYII=\" width=\"394\" height=\"73\"\u003e \u003cspan class=\"InlineEquation\"\u003e \u003c/span\u003e (2) where \u003cem\u003eP\u003c/em\u003e\u003csub\u003e\u003cem\u003ein\u003c/em\u003e\u003c/sub\u003e is the input light energy.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Incident photon to current conversion efficiency (IPCE) for DSSCs\u003c/h2\u003e \u003cp\u003eThe IPCE measurements were taken using a Newport Model 70528 Oriel Monochromator Illuminator. The IPCE spectrum is a plot of the ratio of the number of output electrons (current) to the input photons (irradiance) as a function of wavelength. The incident-photon-to-current conversion efficiency indicates the current the cell will produce when irradiated with photons of a particular wavelength.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Electrical conductivity\u003c/h2\u003e \u003cp\u003eThe conductivity of the electrolytes has been calculated from impedance data obtained by electrochemical impedance spectroscopy (EIS). Room-temperature electrical conductivity data for composite phthaloyl chitosan-TPAI with additives, using a tert-butyl pyridine electrolyte system, are reported. The conductivity at room temperature of 0 wt.% of 1.1 x 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e(S/cm), 2 wt.% of 9.0 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e(S/cm), 4 wt.% of 8.6 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e(S/cm) ,6 wt.% of 1.0 x 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e(S/cm) and 8 wt.% of 9.0 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e(S/cm),\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComposition of gel polymer electrolytes with additives, tert-butyl pyridine (TBP)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWt %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePEO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePhCh\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDMF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTPAI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eI\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eTBP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2 wt%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e37.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e22.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e1.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4 wt%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e36.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e21.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e4.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 wt %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e29.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e35.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e21.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8 wt %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e34.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e20.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e8.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTo measure ionic conductivity, we have sandwiched free-standing biopolymer electrolyte films between steel electrodes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe electrical conductivity was evaluated using the formula σ\u0026thinsp;=\u0026thinsp;R\u003csub\u003eb\u003c/sub\u003e (l/A), where σ\u0026thinsp;=\u0026thinsp;l / (R\u003csub\u003eb\u003c/sub\u003e \u0026middot; A) σ is the ionic conductivity, R\u003csub\u003eb\u003c/sub\u003e is the bulk resistance, l\u0026thinsp;=\u0026thinsp;0.285 cm is the thickness of the sample, and A\u0026thinsp;=\u0026thinsp;2.2707 cm\u003csup\u003e2\u003c/sup\u003e is the area of the given sample.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2. \u003cem\u003eJ-V\u003c/em\u003e Characteristics of DSSCs\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the \u003cem\u003eJ\u0026ndash;V\u003c/em\u003e curves of the DSSCs fabricated with different TBP contents in the polymer electrolytes. The corresponding performance parameters are summarised in Table\u0026nbsp;2. It can be observed that the DSSC with 8 wt% TBP exhibits a higher current density of 17.23 mA cm-2 and a higher efficiency of 8.74% compared to the other DSSCs.On the other hand, without additives added in the polymer electrolyte, the solar cell efficiency exhibited was 7.10%, with a \u003cem\u003eV\u003c/em\u003e\u003csub\u003eoc\u003c/sub\u003e of 0.65 V.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe V\u003csub\u003eoc\u003c/sub\u003e and FF values increased with the addition of TBP and as the TBP concentration increased. The Jsc value decreased slightly with increasing TBP concentration but remains above 16 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. Consequently, the total conversion efficiency increased remarkably from 7.10% for 0 wt % of TBP to 8.74% for eight wt % of TBP (Table\u0026nbsp;2). Considering these results, the Fermi level of TiO2 may have shifted to a more negative potential due to TBP adsorption on the TiO2 surface, resulting in a significant difference between the Fermi level and the redox potential, thereby improving V\u003csub\u003eoc\u003c/sub\u003e [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. At a more negative potential, charge recombination between injected electrons in TiO2 and the cations of a Ru complex (N3 dye) is reported to be relatively slow [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Taking this point into consideration, recombination between injected electrons and triiodide ions under irradiation may reduce photocurrent. However, it may be implied that the recombination rate is slow since the J\u003csub\u003esc\u003c/sub\u003e is still, on average, greater than 16 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. Thus, although the Fermi potential has shifted to a more negative value, the reduced electron leakage has left Jsc almost unchanged. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the addition of TBP (і) has nearly relinquished electron recombination and prevented a significant decrease in photocurrent at relatively low voltage and (іі) led to an increase in V\u003csub\u003eoc\u003c/sub\u003e by increasing the\u003c/p\u003e \u003cp\u003ePerformance parameters of DSSCs Table\u0026nbsp;2\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWt %TBP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eσ(Scm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e,At RT)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJ\u003csub\u003esc\u003c/sub\u003e (mA/cm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eV\u003csub\u003eoc\u003c/sub\u003e (V)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFill Factor (FF)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eη (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0% TBP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.011082\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e7.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2% TBP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.009017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e7.68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4% TBP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.008571\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e7.76\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6% TBP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.010026\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8.06\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8% TBP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.008976\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8.74\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003edifference in potential between the Fermi level and redox level, and (ііі) increasing FF values. The effect of TBP on the surface would be similar to that of metal oxide blocking layers, which inhibit recombination between injected electrons and triiodide ions and consequently improve the V\u003csub\u003eoc\u003c/sub\u003e of the solar cells, as reported by several groups [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The current density obtained for 8 wt % of TBP is higher compared to the others. The fill factor and voltage also increased in the polymer electrolyte system with additives compared to those without a TBP electrolyte. The higher dye adsorbed also leads to increased light absorption in the photo-electrode, and thus gives rise to higher \u003cem\u003eJ\u003c/em\u003e\u003csub\u003e\u003cem\u003esc\u003c/em\u003e\u003c/sub\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Incident photon to current conversion efficiency (IPCE\u003cb\u003e)\u003c/b\u003e\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the IPCE spectrum for DSSCs with and without additives. The dye sensitized solar cells can efficiently convert visible light to photocurrent from 300 nm to around 750 nm. As can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the IPCE value reached is 72.9% at 530 nm for the cell with 8 wt% of TBP electrode. [He et al.] reported that TBP as co-adsorbates improved the IPCE performance of DSSCs based on zinc phthalocyanine photosensitizers [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. They suggested that reduced surface aggregation due to the coadsorbates, which suppresses quenching processes due to energy transfer or charge transfer reactions between the aggregated molecules and/ or between molecules in the aggregates and monomers, leads to the improved IPCE performance. In addition, [Khazraji et al.] reported that the IPCE performance of a merocyanine dye-sensitized TiO2 solar cell is enhanced by the addition of a co-adsorbate, which prevents the formation of a dimer whose electron-injection performance is lower than that of the monomer [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Higher IPCE values indicate that the electron transfer process from excited dye molecules to the conduction band of semiconductors occurs effectively [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This indicates that the dye adsorption on the semiconductor surface is better in the 8 wt % of TBP.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAs can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the IPCE of the DSSC with photoanode 0 wt% of TBP,2 wt% of TBP, 4 wt% of TBP,6 wt% of TBP and 8 wt% of TBP reached a maximum value of 61.5%,66.0%, 66.82%, 69.0% and 72.9% at 530 nm. Although the current density is approximately the same, the voltages differ due to the additives. From Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, we can also observe that the IPCE value for the photoanode with 0 wt% TBP electrolyte is maximum at 530 nm, at 61.5%. After adding additives, the IPCE increased significantly over the long-wavelength range (300-800nm).\u003c/p\u003e \u003cp\u003eThe broader IPCE spectrum suggests improved interaction between dye molecules and the semiconductor substrate. These interactions lead to changes in the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the dye adsorbed on the semiconductor surface, resulting in the broadening of the action spectrum of IPCE [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eDye-sensitized solar cells containing phthaloylchitosan gel polymer electrolyte-based DSSCs were fabricated. The 8 wt.% TBP blend shows the best Voc and ff values for a DSSC based on a ruthenium dye, which were remarkably improved by the addition of TBP. In contrast, the Jsc values decreased slightly with increasing TBP, except at the 8 wt.% TBP composition. Consequently, the total conversion efficiency increased remarkably from 7.68% to 8.74%. compared to all other films. The improved Voc was probably due to the suppression of recombination between electrons and I\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003eions (dark current).\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eBoqiyev Sohibjon performed the experiments, analyzed the data, and wrote the first draft. Abdukarimov Abdulaziz supervised the study and revised the manuscript. Shahan Shah contributed to materials preparation and data interpretation. All authors reviewed and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe thank the University of Malaya for experimental and lab support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eO\u0026rsquo;Regan, B. \u0026amp; Gra \u0026uml;zel, M. A low-cost, high-efficiency solar cell based on dyesensitized colloidal TiO2 films. Nature 353, 737\u0026ndash;740 (1991).\u003c/li\u003e\n\u003cli\u003eYella, A. et al. Porphyrin-Sensitized Solar Cells with Cobalt (II/III)\u0026ndash;Based Redox\u003cbr\u003e Electrolyte Exceed 12 Percent Efficiency. Science 334, 629\u0026ndash;634 (2011). \u003c/li\u003e\n\u003cli\u003eH-slee, S-H bae, C-H han,S S sekhon,Efficiency enhancement of dye-sensitized solar cells with addition of additives (single/binary) to ionic liquid electrolyte, Bull. Mater. Sci., Vol. 35, No. 6, November 2012, pp. 1003\u0026ndash;1010. c Indian Academy of Sciences.\u003cstrong\u003e,\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eFukui A, Komiya R, Yamanaka R, Islam A, Han L: Effect of a redox electrolyte in mixed solvents on the photovoltaic performance of a dyesensitized solar cell. Sol Energy Mater Sol 2006,90:649.\u003c/li\u003e\n\u003cli\u003eWang P, Zakeeruddin SM, Humphry-Baker R, Moser JE, Gr\u0026auml;tzel M: Molecular-scale interface engineering of TiO2 nanocrystals: improve the efficiency and stability of dye-sensitized solar cells. Adv Mater 2003, 15:2101.\u003c/li\u003e\n\u003cli\u003eWang H, Bell J, Desilvestro J, Bertoz M, Evans G: Effect of inorganic iodides\u003cbr\u003e on performance of dye-sensitized solar cells. J Phys Chem C 2007, 111:15125\u003c/li\u003e\n\u003cli\u003eNakade S, Kanzaki T, Kubo W, Kitamura T, Wada Y, Yanagida S: Role of\u003cbr\u003e electrolytes on charge recombination in dye-sensitized tio2 solar cell (1): the case of solar cells using the I-/I3- redox couple. J Phys Chem B 2005, 109:3480.\u003c/li\u003e\n\u003cli\u003ePaulsson H, Kloo L, Hagfeldt A, Boschloo G: Electron transport and recombination in dye-sensitized solar cells with ionic liquid electrolytes. J Electroanal Chem 2006, 586:56.\u003c/li\u003e\n\u003cli\u003eHuang, S. Y.; Schlichtho\u0026uml;rl, G.; Nozik, A. J.; Gra\u0026uml;tzel, M.; Frank, A. J. J. Phys. Chem. 1997, 101, 2576-2582.\u003c/li\u003e\n\u003cli\u003eXiong, B. T.; Zhou, B. X.; Zhu, Z. Y.; Gao, T.; Li, L. H.; Cai, J.;\u003cbr\u003e Cai, W. M. Chin. J. 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Commun. 2000, 2231-2232. (b) Kay, A.; Gra\u0026uml;tzel, M. Chem. Mater. 2002, 14, 2930-2935. (c) Diamant, Y.; Chen, S. G.; Melamed, O.; Zaban, A. J. Phys. Chem. B 2003, 107, 1977-1981. (d) Palomares, E.; Clifford, J. N.; Haque, S. A.; Lutz, T.; Durrant, J. R. J. Am. Chem. Soc. 2003, 125, 475-482.\u003c/li\u003e\n\u003cli\u003eHe, J.; Benko\u0026uml;, G.; Korodi, F.; Polı\u0026acute;vka, T.; Lomoth, R.; A\u0026deg; kermark, B.; Sun, L.; Hagfeldt, A.; Sundstro\u0026uml;m, V. J. Am. Chem. Soc. 2002, 124, 4922-4932\u003c/li\u003e\n\u003cli\u003eKhazraji, A. C.; Hotchandani, S.; Das, S.; Kamat, P. V. J. Phys. Chem. B 1999, 103, 4693-4700.\u003c/li\u003e\n\u003cli\u003eK. Hara, T. Horiguchi, T. Kinoshita, K. Sayama, H. Sugihara, H. Arakawa, Highly efficient photon-to-electron conversion with mercurochrome sensitized nanoporous oxide semiconductor solar cells, Solar Energy Materials \u0026amp; Solar Cells. 64 (2000) 115-134.\u003c/li\u003e\n\u003cli\u003eVarishetty Madhu Mohan, Kenji Murakami, Dye sensitized solar cell with carbon doped (PAN/PEG) polymer quasi-solid gel electrolyte, V.M.Mohan et.al / Journal of Advanced Research in Physics 2(2), 021112 (2011)\u003c/li\u003e\n\u003cli\u003eM. Lu, M. Liang, H.-Y. Han, Z. Sun and S. Xue, J. Phys. Chem. C, 2011, 115, 274. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ruthenium dye, DSSCs, IPCE, TBP, gel polymer electrolytes, Conductivity","lastPublishedDoi":"10.21203/rs.3.rs-8534346/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8534346/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePhthaloyl-chitosan (PhCh) blended with polyethene oxide (PEO) forms the host in a gel polymer electrolyte with a composition of 5.04 wt.% PhCh-1.26wt.% PEO-31.51wt.% DMF-37.81 wt.% EC-24.38wt.% TPAI(+\u0026thinsp;I\u003csub\u003e2\u003c/sub\u003e). To this composition X wt. % of tert-butyl pyridine (TBP) [X\u0026thinsp;=\u0026thinsp;0, 2, 4, 6, 8] has been added. The conductivity of the electrolytes has been calculated from impedance data obtained using electrochemical impedance spectroscopy (EIS)\u0026mdash;the GPEs with different wt. % TBP exhibits a conductivity of 9 mS cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which is slightly lower than the GPE without TBP being 11 mS cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eat room temperature. Dye-sensitized solar cells (DSSCs) have been assembled with a ruthenium-based dye as sensitizer. The photocurrent density-voltage (\u003cem\u003eJ-V\u003c/em\u003e) characteristics of the DSSCs have been measured under white-light illumination of 1000 W m-2, with an active area of 0.20 cm\u003csup\u003e2\u003c/sup\u003e. The electrolytes containing 8 wt.% TBP exhibit the highest efficiency of 8.74% with \u003cem\u003eJ\u003c/em\u003e\u003csub\u003e\u003cem\u003esc\u003c/em\u003e\u003c/sub\u003e= 17.23 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003eoc\u003c/em\u003e\u003c/sub\u003e = 0.72 V and \u003cem\u003eFF\u003c/em\u003e 0.70. The incident photon to current conversion efficiency (IPCE) for DSSC was characterised using the Newport Model 70528 Oriel Monochromator Illuminator\u0026mdash;the DSSC with eight wt. % TBP shows the highest quantum efficiency of 72.9% at 530 nm.\u003c/p\u003e","manuscriptTitle":"Efficiency enhancement of dye-sensitized solar cells (DSSCs) using a gel polymer electrolyte added with tert-butyl pyridine.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-14 04:59:27","doi":"10.21203/rs.3.rs-8534346/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"992a7fb7-a54f-44b2-9948-b55cc00e6cc7","owner":[],"postedDate":"January 14th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-25T12:38:28+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-14 04:59:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8534346","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8534346","identity":"rs-8534346","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}