Improving the efficiency of polymer solar cells based on chitosan@PVA@rGO composites via gamma-irradiated treatment of rGO nanoparticles

Abstract

Polymer solar cells (PSCs) are growing as attractive contenders for renewable energy technologies given their low cost, adaptability, and environmental sustainability, rendering them valuable in combating climate change. Interestingly, this work investigates the augmentation of photon absorption and overall efficiency in low-cost, effective active layers (ALs) via gamma irradiation treatment, thereby raising the number of active absorption sites. For the first time, novel Chitosan@PVA@rGO (CPG) composite sheets were created as AL materials and treated to varied dosages of in-situ gamma irradiation (0, 10, 20, 30, and 40 KGy) to optimize their microstructural and physicochemical characteristics. The processed ALs were subjected to comprehensive tests, which included J–V variable evaluation as well as evaluations of microstructure, porosity, morphology, contact angle, optical characteristics, and electrochemical impedance spectroscopy (EIS). The findings reveal that the composites' surface properties got better gradually as gamma irradiation dosages grew; peak performance was reached at 30 KGy (75.9 % apparent porosity and roughness parameter Ra = 6.22 μm). Extended gamma irradiation resulted in increased DSSC efficiency, which reached 6.85 % after 10 KGy and 7.63 % after 20 KGy. High-energy gamma photons boosted mobility and decreased resistive limits by reducing carrier recombination and facilitating charge carrier movement inside CPG compounds. This increased the longevity and charge transfer efficiency of the solar cell. After 30 KGy alteration, the CPG AL's optimized efficiency of 8.78 % and J_sc of 20.23 mA/cm² indicate a 44.3 % improvement in efficacy over the pristine material. The insertion of oxygen-enriched free radicals into the CPG structure is responsible for the improvement in photovoltaic efficiency because it creates continuous pathways for fast electron transport. This work provides an innovative perspective on the use of heteroatom-doped ALs in PSCs by highlighting the benefits of co-doping and regulated heteroatom species.