Enhanced Fill Factor and Power Conversion Efficiency of Single Oxide Ferroelectric Photovoltaic Devices with Designed Nanostructures

The ferroelectric photovoltaic effect has promising potential for the next generation of solar cells. However, due to disadvantages such as wide bandgap and low fill factor (FF), the power conversion efficiency (PCE) values reported in ferroelectric photovoltaic devices remain considerably below expectations. Herein, enhanced photovoltaic effect in the films with the nanostructure of ferroelectric nanocrystalline particles embedded in the amorphous or poor crystalline matrix is investigated. The nanostructures are realized by controlled crystallization and doping in Zn_0.92-xCu_x(Fe_0.04Li_0.04)O (ZCFLO) films. Benefiting from the improved carrier dynamic regulation in ferroelectric/boundary nanostructures and narrowed bandgap, the designed ZCFLO photoferroelectrics films exhibit high efficiency photovoltaic effect under AM 1.5G light, manifesting above-bandgap photovoltage, markedly improved FF (83.4%), switchable photoresponse (50.3 mA W⁻¹), and high PCE (14.4%). Meanwhile, the simple method presented in this work is fully compatible with large-scale manufacturing processes and may find applications in cost-efficiency optoelectronic devices.