Seeded Space-Limited Crystallization of CH3NH3PbI3 Single-Crystal Plates for Perovskite Solar Cells

The synthesis of certain perovskite single crystals (SCs), including CH3NH3PbI3, through asymmetric crystallization is difficult, mainly because of the large difference in solubility of the precursors and/or the intrinsic nonpreference for growth in a direction along the substrate. Herein, an effective method is reported, seeded space-limited inverse-temperature crystallization (SSLITC), for growing CH3NH3PbI3 SC plates having micrometer-scale diameters. In this process, a seed CH3NH3PbI3 crystal is incorporated within a confined space to promote crystallization. Crystal plates having lateral dimensions of up to 2 mm are grown successfully. These SCs and a polymer conductive glue to fabricate perovskite solar cells on flexible substrates are used. One such device exhibits a maximum external quantum efficiency of 96%, a high photocurrent of 22 mA cm(-2), and a power conversion efficiency of greater than 4%. In addition, a device prepared without any encapsulation exhibits reasonable stability, suggesting a promising future for SC-based perovskite solar cells. It is anticipated that the SSLITC method proposed herein could open up new avenues for synthesizing various types of organic/inorganic perovskite SCs for applications in modern electronics.