Enhanced photovoltaic effect in Bi2FeMo0.7Ni0.3O6 ferroelectric thin films by tuning the thickness
Ferroelectric photovoltaic (FE-PV) materials with excellent photocurrent output have stimulated many recent studies in solar energy material fields. How to improve photocurrent by designing the structure of materials and devices based on a simple way is still a challenge. Here, enhanced photocurrent in Bi2FeMo0.7Ni0.3O6 (BFMNO) ferroelectric thin films is achieved by tuning the thickness of the thin films. With the increase of the thickness, the short circuit current increases firstly and then decreases. The maximum short circuit current reaches 0.09 mA/cm2 under 100 mW/cm2 when the thickness is 700 nm, which is nearly triple that of the thin film with the thickness of 570 nm. It is proposed that the compensation effect of the driving force comprised of the depolarization field and build-in field is the main reason to enhance the photocurrent. This work highlights a simple approach to enhance photocurrent of FE-PV materials based on the tuning of thickness.