Document Type : Research Paper
Authors
1
FDepartment of Polymer and Color Engineering, Amirkabir University of Technology, P.O. Box: 15875-4413, Tehran, Iran
2
Department of Polymer and Color Engineering, Amirkabir University of Technology, P.O. Box: 15875-4413, Tehran, Iran
Abstract
Hypothesis: Third-generation pioneering solar cells with perovskite structures require targeted modifications to further enhance their photovoltaic properties specifically through reduction of structural defects and improvement of
charge carrier exchange and mobility. For this purpose, the use of additives (small molecules and especially polymers) has been widely considered in recent years. Small molecules often provide weaker synergistic effects compared to polymers due to their lower molecular weight, higher volatility, reduced potential for surface modification and bonding, and the absence of influential parameters such as glass transition temperature. Even insulating polymers, at very low concentrations within the perovskite structure, have introduced remarkable features for tuning photovoltaic properties, while conjugated polymers additionally play a significant role in facilitating charge carrier transport. The morphological or aggregative properties of conjugated polymers yield distinct photophysical behaviors that directly affect device efficiency In this study, the aggregative modifications of poly(3-hexylthiophene) (P3HT), as a conventional charge carrier, were systematically investigated in order to evaluate the role of enhanced J-type aggregation in charge transfer, recombination reduction, and consequently photovoltaic property enhancement
Methods: To increase J-type aggregation and achieve nanowire structures, after P3HT synthesis, ultrasonic treatment, solution processing, and finally ultraviolet irradiation were applied in sequence. The prepared solutions were then introduced as anti-solvents during the spin-coating process of perovskite thin film formation
Findings: The results demonstrated that P3HT nanowires significantly improved holes transport and reduced bimolecular recombination. Solvent engineering combined with ultraviolet irradiation led to J-type aggregation and increased conjugation length, thus enhancing electronic coupling. Furthermore, photovoltaic tests revealed considerable improvement in the key performance parameters of the cells, as the power conversion efficiency (PCE) was increased from 11.83% to 17.92%.
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