The distinct visible-blind narrowband near-infrared (NIR) photodetection behaviors in the perovskite/polymer hybrid photodetectors (PDs) have been investigated. The narrowband NIR response in the hybrid PDs is realized through the buildup of the space charges at the perovskite/polymer interface. The semiconducting perovskite layer acts as an internal NIR bandpass due to its high absorption to the visible light and high transparency to the NIR light. It also acts as an excellent hole-transporting layer, facilitating the efficient extraction of the holes generated in the low band gap NIR light-absorbing polymer blend layer. The hybrid PDs thus demonstrated have a -3 dB cutoff frequency of 300 kHz, providing an exciting option for a plethora of applications in bioimaging, environmental detection, and security monitoring.
Keywords: low band gap polymer; narrowband; near-infrared photodetector; perovskite; space charge.