Robust Visible-Blind Wearable Infrared Sensor Based on IrP2 Nanoparticle-Embedded Few-Layer Graphene and the Effect of Photogating

It is challenging to realize a visible-blind infrared photodetector as the materials that absorb infrared light also absorb visible light. Here, we report the synthesis of IrP2 nanoparticle-embedded few-layer graphene by one-step solid-state pyrolysis and its application in visible-blind infrared sensing. A linear photodetector device was fabricated by drop casting IrP2 nanoparticle-embedded few-layer graphene onto a flexible PET substrate with two gold electrodes separated by similar to 16 mu m. The photoconductive gain was found to be as high as similar to 145% with response and decay times of similar to 0.4 and similar to 2.8 s, respectively, under 1550 nm irradiation of 800 mW cm(-2). The room-temperature responsivity was similar to 1.81 A at 80 mW cm(-1) and similar to 0.54 A W-1 at a high incident power of similar to 2200 mW cm(-2) under a bias of 1 V. Interestingly, the device showed response even in the long-wavelength infrared region, but no response was found under visible light. The embedded IrP2 nanoparticles act as trap centers inducing photogating in the device, and the average trap state energy was estimated to be similar to 16.5 +/- 1.5 meV from the temperature-dependent photocurrent studies. The device was found to be immune to air exposure and bending, suggestive of use a a wearable sensor.

Automated summary

A visible-blind infrared photodetector was successfully realized by embedding IrP2 nanoparticles into few-layer graphene through solid-state pyrolysis, showing high responsivity and response speed. The device exhibited sensitivity to long-wavelength infrared radiation but remained unresponsive to visible light, making it a promising candidate for wearable sensor applications.