Room temperature synthesis of perovskite (MAPbI₃) single crystal by anti-solvent assisted inverse temperature crystallization method

Hybrid organic-inorganic lead halide perovskites have shown excellent photovoltaic performance due to their remarkable unique optoelectronic properties in their polycrystalline thin film; however their performance is limited due to the presence of grain boundaries. It is noted that perovskite single crystals have larger domains and hence significantly low trap density with higher diffusion length. In the present manuscript, we report the anti-solvent modified inverse-temperature-crystallization (ITC) approach to synthesis perovskite (MAPbI₃) single crystals (1 cm in size) of superior opto-electronic quality at room temperature (30 °C/RT). To accomplish this first we have developed an understanding on the role of various growth parameters such as temperatures and precursor compositions (amount of anti-solvent and solution molarity) during crystal growth via ITC process in attaining the suitable condition for crystal. Careful control over the amount of anti-solvent and solution molarity helps in realizing the crystal growth even at very high temperatures (140 °C) as well as at room temperature. Specifically, the quality of RT crystals was compared with control (60 °C) crystals and high temperature (140 °C/HT) crystals using XRD, vis-NIR absorbance, photoluminescence (PL) and scanning electron microscope (SEM) analysis. The RT single crystals are compared with the control and HT single crystal.