Enhanced Self-Biased Photoelectric Performance of BiVO4 Ceramics via Nitrogen Doping

The anomalous photovoltaic (APV) effect with an above-bandgap photovoltage and polarization-dependent photocurrent shows unique advantages in the field of photoelectronics in comparation to the conventional semiconductor photovoltaic effect. With the combination of the flexoelectric effect, the APV effect can be extended to a large pool of materials systems than to ferroelectric materials. Herein, we present the self-biased photoelectric performance of centrosymmetric BiVO4 (BVO) driven by the APV effect induced by applying unidirectional mechanical polishing. In addition, nitrogen doping was realized on BVO ceramics by annealing treatment under a gaseous NH3 environment to further optimize the photovoltaic outputs and the photoresponse range. It was observed that N doping effectively improves its photoabsorption at the visible light range. Under zero external bias, in comparison to pure BVO, N-doped BVO exhibits an open-circuit voltage improved from 6 to 14.1 V and a short-circuit photocurrent improved from 0.5 to 0.9 nA when illuminated by a 405 nm laser at 100 mW/cm(2). Besides, the short-circuit photocurrent shows a fast response time and a high light on/off ratio above 10(3). These findings verify the potential of N-doped BVO ceramics for self-powered photoelectric applications despite the centrosymmetric structure.