Significantly enhanced photoelectric/photovoltaic performance in AgNbO₃-based solid-solution ceramics

Anomalous photovoltaic effect of ferroelectrics is receiving intensive research interests. However, many ferroelectric materials struggle to effectively harness the solar spectrum due to their large bandgaps. AgNbO3 has partial visible-light response, but weak photoelectric/photovoltaic performance. Here, we prepare and report the photoelectric/photovoltaic performance of Ag1-xKxNbO3 solid-solution ceramics. The results indicate that all the investigated ceramics exhibit a narrow bandgap (Eg approximate to 1.95 eV); mechanical polishing further improves lightabsorption, enhancing photoelectric response. Composition-driven improvements in photoelectric/photovoltaic performance were observed, which is closely linked to the enhanced ferroelectricity. The poling electric-field effect on photoelectric/photovoltaic performance and ferroelectric properties reveals that the open-circuit voltage (Voc) and short-circuit current (Jsc) are directly proportional to the remnant polarization until the applied field reaches 100 kV/cm. Upon illuminating the polarization-saturated ferroelectric ceramic (x = 0.07) surface, the maximum Voc (=8 V) and Jsc (=1 mu A/cm2) were achieved, which are 10 times and 35 times larger, respectively, than those of AgNbO3 ceramics.