Enhancing Photovoltaic Performance of Aromatic Ammonium-based Two-Dimensional Organic-Inorganic Hybrid Perovskites via Tuning CH···π Interaction

摘要

Phenethylammonium (PEA)-based 2D perovskite is an interesting example of 2Dperovskites, serving as the gateway for further introduction of functional conjugatedorganic cations into 2D perovskites for a variety of applications, forexample, photovoltaics. However, the efficiency of photovoltaic devices based onPEA 2D perovskites only achieved ≈7% for = 3, which was significantlylower than that achieved for other cation-based 2D perovskites. Here, byintroducing propyl ammonium (C3A) into the PEA-based 2D perovskites, thedevice efficiency is improved to 10% for 1:1 C3A:PEA-based 2D perovskites(= 3). Further investigation reveals that tuning the CH···π interaction(between C3A and PEA or between two PEA molecules) can have multiplebeneficial impacts on such modified 2D perovskites, including a) removal ofundesirable n ¼ 1 phase, b) lowering the density of trap states, and c) achievinglarger crystalline grains. Additionally, after substitution with 50% C3A, otheraromatic ammonium cation-based 2D perovskites (= 3) also show similarefficiency enhancement in their photovoltaic devices, thus exhibiting the generalapplicability of this method. The results of this study highlight that the strategictuning of non-covalent interactions (such as CH···π interaction) is a viable andimportant method to further develop 2D perovskites for photovoltaics.