1 + 1 > 2 Effect: Constructing Perovskite Heterostructures for Boosting Phototransistor Performance

The diverse applications of photodetection technology in daily life demand photodetectors with tailored properties. The optimal photodetection system depends on its application, where aspects such as sensitivity, spectral selectivity, noise, and response speed play the critical roles. Perovskite photodetectors, mainly working on photodiodes and photoconductors, have reached great achievements covering a large spectral range from ultraviolet to infrared. To overcome existing limitations in sensitivity, noise, and speed of state-of-the-art systems, advances in device architectures and material strategies are needed. In this Review, we briefly introduce the physical mechanism of phototransistors and discuss recent developments in perovskite phototransistors. We highlight the fundamental trade-offs between parameters for single-material-based devices and clarify how heterostructure devices, consisting of an ultrahigh-mobility channel sensitized with strongly absorbing perovskites, can circumvent these limitations and lead to a next generation of highly sensitive photodetectors. Future directions for their application in high-sensitivity photodetection are proposed.