An Above‐Room‐Temperature Ferroelectric Organo–Metal Halide Perovskite: (3‐Pyrrolinium)(CdCl3)

Abstract

Hybrid organo–metal halide perovskite materials, such as CH 3 NH 3 PbI 3, have been shown to be some of the most competitive candidates for absorber materials in photovoltaic (PV) applications. However, their potential has not been completely developed, because a photovoltaic effect with an anomalously large voltage can be achieved only in a ferroelectric phase, while these materials are probably ferroelectric only at temperatures below 180 K. A new hexagonal stacking perovskite‐type complex (3‐pyrrolinium)(CdCl 3) exhibits above‐room‐temperature ferroelectricity with a Curie temperature Tc=316 K and a spontaneous polarization Ps=5.1 μC cm−2. The material also exhibits antiparallel 180° domains which are related to the anomalous photovoltaic effect. The open‐circuit photovoltage for a 1 mm‐thick bulky crystal reaches 32 V. This finding could provide a new approach to develop solar cells based on organo–metal halide perovskites in photovoltaic research.