Narrow Bandgap Inorganic Ferroelectric Thin Film Materials

Abstract Harvesting solar energy to solve the energy crisis and environmental pollution is a research hotspot in the photovoltaic industry today. Conventional ferroelectric materials have a bandgap between 3.0 and 3.8 eV, and their low absorption coefficients and photocurrent densities limit the photovoltaic applications of ferroelectric materials. Inorganic ferroelectric thin film materials with narrow bandgap (1.1–2.0 eV) have high optical absorption coefficient and broad spectral response, wide bandgap tuning range (1.2–3.0 eV), as well as high photocurrent density and switchable ferroelectric photoelectric effect, which have great potential for photovoltaic and optoelectronic applications in solar cells, photodetection, photocatalysis. This review summarizes the recent developments of narrow bandgap inorganic ferroelectric thin‐film materials and aims to stimulate research interest and efforts in ferroelectric photovoltaic materials.