Enhanced photocurrent in ferroelectric Bi_0.5Na_0.5TiO₃ materials via ferro-pyro-phototronic effect

The photocurrent generated by ferroelectric materials via the photovoltaic effect has latent applications in opto-electronic devices due to the introduction of a polarization-induced charge carrier separation and transport, which is absent in semiconducting p-n junctions. However, the precise mechanism of photocurrent production in photoelectric devices by a range of ferroelectric materials remains a topic of continued interest. Here we report a significant enhancement in the photocurrent of a ferroelectric Bi_0.5Na_0.5TiO₃-based photoelectric device by ferro-pyro-phototronic effect. When compared with the generated photocurrent under illumination alone, the peak and platform photocurrents induced by the simultaneous use of both light and heating can be increased by 131% and 57%, respectively. The increase in photocurrent is found to increase with temperature, where the mechanism of enhancement is associated with the increase in pyroelectric coefficient, photoexcited carrier concentration and carrier mobility at higher operating temperatures. These factors also lead to a rapid response time of 84.2 ms. This work provides guidelines for photocurrent promotion in ferroelectric devices, pushing forward the potential applications of ferroelectric materials for self-powered photodetectors.