Narrowband Near-Infrared Photodetector Enabled by Dual Functional Internal-Filter-Induced Selective Charge Collection

The spectral selective detection of the near-infrared (NIR) signals is important for biological sensing, healthy monitoring, and intelligent communication. Herein, a new method to fabricate a visible-blind NIR-sensitive narrowband photodetector (NPD) with excellent comprehensive performances is reported. The organic bulk heterojunction (OBHJ) thin film, based on an NIR-sensitive organic acceptor, is employed to provide fast photoresponse, with adjustable cutoff edge. The key strategy of introducing a solution-processable optical/electric bifunctional internal filter (CH3NH3PbI3 (MAPbI(3))/CuSCN) realizes the selective collection of the NIR-induced charge carriers. Further combined with the suitable energy level and high mobility of the MAPbI(3)/CuSCN layer, the extraction of NIR-light-induced charges from OBHJ is promoted efficiently. The NPD with optimized structure exhibits narrowband NIR response (full width at half maximum (FWHM) < 100 nm) with maximum external quantum efficiency value up to 74.26% and detection limit down to 3.6 pW cm(-2), both of which are the best values among the ever reported NIR NPDs. The highest responsivity reaches 0.485 A W-1 in the NIR region, with a large linear dynamic range of 162 dB. The specific detectivity is close to 10(13) Jones, enabling the device to detect weak NIR signals.

Automated summary

The new method reported in this study fabricates a visible-blind NIR-sensitive narrowband photodetector with excellent comprehensive performances, including narrowband NIR response, high quantum efficiency, and outstanding detection capabilities. This NPD offers the best values among all ever reported NIR NPDs, with a maximum external quantum efficiency value of up to 74.26% and a detection limit as low as 3.6 pW cm(-2), making it highly sensitive to weak NIR signals.