Bipolar dual-broadband photodetectors based on perovskite heterojunctions
Yu Li, Fumin Guo, Shanshan Yu, Jian Wang, Shihe Yang
Abstract
Abstract The development of efficient photodetectors for color recognition is of great importance for many applications. In this paper, we report a novel bipolar dual-broadband photodetector equipped with a perovskite heterojunction, with bidirectional broadband responses in the short-wavelength and long-wavelength regions at zero bias voltage, enabled by a charge separation reversion mechanism. The unique aerosol–liquid–solid technique allowed the perovskite heterojunction to be fabricated by successively depositing wide-bandgap perovskite (WBP) and narrow-bandgap perovskite (NBP) layers directly on the transparent substrate. For photodetectors based on the perovskite heterojunctions, the short-wavelength photons were depleted by the bottom WBP layer and generated negative responses, while the long-wavelength photons were absorbed by the top NBP layer and generated positive responses. Moreover, the demarcation wavelength between the bipolar responses and the cut-off wavelength can be easily tuned by adjusting the bandgaps (or compositions) of the bottom and top perovskite layers.