Broadband photodetectors based on enhanced photothermal effect of polymer encapsulated graphene film

Abstract

In this work, a broadband photodetector is constructed by coating a photothermal layer on a thermistor. The photothermal effect effectively convert light energy into heat, which is then reflected by voltage variation of the thermistor. A highly efficient photothermal film is synthesized by encapsulating a reduced graphene oxide (rGO) film into a polydimethylsiloxane (PDMS) layer. Benefiting from the excellent photothermal effect, the photothermal detector based on the rGO/PDMS displays a good linear response, a high responsivity, a quick response, and a broad range of spectral response (400–1300 nm). The responsivity for simulated sunlight at 0.8 kW/m2 reaches a high value up to 176.9 V/W with response-recovery time of ~80 s. And laser emissions of 6.37 kW/m2 at 473, 532, 808 nm also can be detected at high responsivities of 15.6, 14.6 and 19.4 V/W respectively. This work not only provides a high performance photothermal film, but also develops a feasible strategy for broadband photodetectors.