Rational design of multiple sections in ferroelectric photovoltaics for enhanced current density

Abstract

Ferroelectric photovoltaic devices (FEPVs) suffer from low current density, which hinders their application. Generally, although an extremely high current density of about 10–100 A cm⁻² is measured on atomic force microscope tips, but only an ultra-low current density is received on photovoltaic cells with an effective working electrode area in the square millimeter scale. This inconsistency in practical devices demands further research to enhance the photocurrent in FEPVs via effective structural design of devices. Herein, multiple sections were designed to construct parallel circuits in devices for enhancing the current density in FEPVs and exploring the relationship between the effective working electrode area and current density. The original film with an effective working electrode area of 28.26 cm² was divided into six sections; consequently, the total working electrode area decreased to 5.76 mm², but the current density increased to 1.069 mA cm⁻², which was 200-fold higher than that for the original film. Concurrently, the open-circuit voltage was 2.74 V, which notably exceeded the theoretical bandgap voltage of the material. This rational design provides a straightforward method for achieving high-performance ferroelectric photovoltaics.