Tuning of photovoltaic response in multiferroic heterojunction photodiodes by a built-in electric field and carrier transport: Effect of magnetization and ferroelectric polarization

Abstract

Photovoltaic devices consisting of multiferroic thin films have been studied extensively for carrier separation regulated by a built-in electric field and the above bandgap. Here, a novel photodiode with photoelectric conversion efficiency (PCE) of 3.70% by introducing TiO2 and NiOx:5%Cu as the electron and the hole transport layers (ETL/HTL) on both sides of multiferroic bismuth layered perovskite oxide Bi2FeCrO6/Bi6Fe1.6Co0.2Ni0.2Ti3O18 (BFCO/BFCNT) heterojunction with the appropriate band gap were reported based on our recent studies. The results showed that BFCNT displays an Aurivillius structure, but BFCO is of a double perovskite, the bandgaps are ∼1.62 eV and 1.74 eV, respectively. The open-circuit voltage, short-circuit current density, and fill factor of the devices are 0.73 V, 10.5 mA·cm-2, and 48.3% separately under the illumination of 100 mW·cm-2 simulated AM 1.5 G solar light. Investigations of the effects of both external electric and magnetic fields on the photovoltaic responses delivered that the magnetization and ferroelectric polarization can effectively tune the built-in electric field and the carrier transport in multiferroics, thus offering an experimental and theoretical basis for further improving the performance of multiferroic photovoltaic devices.