High temperature resistance and wide-spectrum detection flexible photodetectors based on PbS quantum dots/Bi2S3 nanorods

Abstract

High temperature resistance and broadband detection are crucial in the application of flexible photodetectors, and it is still challenging to achieve high quality performance using low-cost and simple fabrication methods. To widen the spectral response range and improve the photoperformance, a photoconductive PbS quantum dots (QDs)/Bi₂S₃ flexible photodetector was fabricated through physical vapor deposition and drop-coating processes on a flexible polyimide. This design is due to the excellent photoresponse of Bi₂S₃ in the ultraviolet and visible regions, and the remarkable tunability and respond of PbS QDs in the infrared band. The device has a broadband photoresponse under 365–1550 nm. The device has the maximum responsivity (R) of 3.59 mA/W and detectivity (D∗) of 4.34 × 10¹⁰ Jones under 638 nm illumination with a light intensity of 0.6 mW/cm². And the response/recovery times are 0.35 s/0.45 s. The device exhibits excellent photoperformance even after multiple bends. When bent by 55 %, the photocurrent remains over 94 % of the initial value. Compared to Bi₂S₃ devices, PbS QDs/Bi₂S₃ flexible photodetectors have a 220-fold increase in on/off ratio. Moreover, the device can operate normally at 180 °C, demonstrating excellent temperature resistance characteristics. This work offers a new approach for designing high-performance flexible electronic devices with high temperature resistance and broadband response.