Efficient and Tunable Enhancement of NLO Performance for Indaceno Based Donor Moiety in A-π-D-π-D-π-A Type First DSSC Design by End Capped Acceptors

Using 2,2'-((4-heptyl-4,9,9-trihexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene)bis(3-oxo-2,3-dihydro-1H-indene-1-yl-2-ylidene)dimalononitrile ( IDIC ) as a starting point, a series of non-fullerene acceptor (NFA) related dyes ( IDIC-R1 - IDIC-R9 ) are designed by varying the end capped fluorinated (1-oxo-1H-inden-3-yl)propanedinitrile moieties ( A1-A6 ). At the M06 level, DFT and TD-DFT based features, including the 6-31G(d,p) basis set, were created to investigate NLO responses to acceptor modification. For IDIC to IDIC-R a significant reduction of band gap (2.01 eV) was observed all the dyes ( IDIC - R1 - IDIC - R9 ) had further reduced band gaps to range between 0.11–2.42. Only IDIC-R3 had higher value that the IDIC - R , demonstrating smaller and bigger levels for and softness properties, and was linked to global reactivity data. Their first ionization potential ranged between the 2.65–7.21 eV to imply that the dyes have strong tendency to lose electrons. The λ max of the dyes ranged between 479–498 nm which were slightly redshifted from the IDIC (476 nm) and IDIC - R (479 nm). NBO analysis showed the S63LP→C61-C62π* with highest stabilization energy of 30.11 kcal/mol. Their electron injection analysis showed that these dyes can be a good anode material against the aluminum and gold electrodes with HIE values range of 6.87–11.49 eV. The intra electronic charge transferring (ICT) process and stability of the title dyes pounds were investigated using frontier molecular orbital (FMO) and natural bond orbital (NBO) research, respectively. For all produced dyes, IDIC - R8 has the highest linear polarizability, and second order hyperpolarizability ( β total ). All the suggested dyes demonstrated possible NLO properties due to their low charge transfer barriers. Scientists would be able to exploit these NLO properties to identify NLO materials for existing applications.