Anomalous photovoltaic effect in Na0.5Bi0.5TiO3-based ferroelectric ceramics based on domain engineering
Xinxiang Yang, Xing Gao, Shan Zhang, Jun Zhao, Xinlei Zhang, Xin Song, Chunxiao Lü, Yong Li, Liwen Zhang, Xihong Hao
Abstract
The anomalous photovoltaic (APV) effect is promising for high-performance ferroelectric materials and devices in photoelectric applications. However, it is a challenge how to tune the APV effect by utilizing the characteristic structure of ferroelectrics. Here, a domain engineering strategy is proposed to enhance the APV effect in lead-free 0.88(Na0.5Bi0.5TiO3)-0.12(Ba1–1.5xSmxTiO3) (NBT-BST) ferroelectric ceramics. By tuning the domain size based on Sm3+ doping, a maximum open-circuit voltage (VOC) of 18.1 V is obtained when Sm3+ content is 0.75%, which is much larger than its bandgap (Eg). The mechanism of this large VOC originates from the multiple positive effects induced by the small-size domain, where decreasing domain size enhances ferroelectric polarization and net interface barrier potential, leading to a large driving electric field. Moreover, the APV effect exhibits a giant temperature sensitivity due to the dramatic evolution of small-size domain in the temperature field. This work sheds light on the exploration of ferroelectrics with APV effect and inspires their future high-performance optoelectronic device applications.