Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV23)
Publication date: 30th March 2023
Perovskite solar cells (PVSCs) have emerged as promising candidates for next-generation photovoltaic devices due to their high efficiency, solution-compatible processability, ease of manufacture and low cost [1]. At present, their certified power conversion efficiency (PCE) has reached 25.7%, approaching to the value of silicon-based solar cells. For PVSCs, additive engineering has become a prevailing strategy to passivate bulk or surface perovskite defects, modulate crystallization processes, and optimize the morphology of perovskite films. These improvements derive impressively high performance and stable PVSCs. In recent years, phenethylammonium iodide (PEA+) and phenethylamine (PEA) are two common and representative additives used to enhance the performance of PVSCs [2]. However, the ammonium- and amine-based additives are often confused due to their structural similarities. Herein, we discuss in detail the difference between PEA+ and PEA additives, including photovoltaic performance, optical properties, electrical properties, and device stability. The results show that PEA passivates iodide vacancies and undercoordinated Pb owing to its Lewis base characteristic. Also, PEA better prevents water invasion, enhances thermal resistance, and inhibits iodide ion migration, thus enhancing PCE and stability. As a result, PEA increases PCE by more than 15% to reach a value of > 21%. More important, the unencapsulated PEA-based device maintained 95.1% and 94.4% of their initial PCE values after storing in an N2 environment for 5000 hours and aging at RH 20% ± 5% at RT for 600 hours, respectively.
The authors thank financial supports from the Ministry of Education (111L9006) and the National Science and Technology Council (NSTC) in Taiwan (111-2634-F-002-016, 111-2124-M-002-021, 111-2628-E-002-009, 110-2923-E-002-007-MY3, 111-2923-E-002-006-MY3). C. C. C. also thanks the financial support from Top University Project of National Taiwan University (112L7810).