Direct and Indirect Measurement of the Electronic Levels in Thermally Aged LDPE (Pre-print to be sumbitted to IEEE- Transactions on Dielectrics and Electrical Insulation)

Thermal aging degrades insulating polymers such as Low-Density Polyethylene (LDPE) through the modification of its electronic structure. The change in electronic levels (such as shallow/deep trap depths, charge injection barriers etc.) with aging is often explained through theories of Isothermal conduction and decay currents (ICC and IDC) and Bipolar Charge Transport (BCT). Although these theories are employed extensively, there is no direct evidence that supports the efficacy of these methods in determining the electronic levels. In addition, there is a considerable discrepancy in the electronic levels estimated from the ICC/IDC and BCT methods. A direct method that serves as an indisputable reference is therefore necessary. This study explores the use of Reflection Electron Energy Loss Spectroscopy (REELS) and Ultraviolet Photoelectron Spectroscopy (UPS) for the same. REELS is used to estimate the bandgap of materials (Eg), while UPS is used to estimate other electronic levels such as Conduction Band Minimum (CBM), Valence Band Maximum (VBM), Vacuum (Evac) levels, and electron affinity (Eea). The electronic levels estimated from this direct method are used to validate the standard indirect methods i.e., (i) fitting ICC/IDC measurements with a two-trap model and (ii) fitting space charge data from Pulsed Electroacoustic Analysis (PEA) with a numerical Bipolar Charge Transport (BCT) model. The results show that the two-trap model demonstrates limited sensitivity to electronic level measurements, whereas the BCT model demonstrates high sensitivity. Supplementary Material File (direct and indirect measurement of electronic levels in thermally aged ldpe.pdf) - Download - 1.12 MB Information & Authors Information Copyright This work is licensed under a Non Exclusive No Reuse License.

Authors Metrics & Citations Metrics Article Usage 152views 106downloads Citations Download citation Balaji Sriram, Nandini Gupta. Direct and Indirect Measurement of the Electronic Levels in Thermally Aged LDPE (Pre-print to be sumbitted to IEEE- Transactions on Dielectrics and Electrical Insulation). Authorea. 28 October 2025. DOI: https://doi.org/10.22541/au.176158441.13823370/v2 DOI: https://doi.org/10.22541/au.176158441.13823370/v2 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.