On-the-surface photoconductive response of pelletized thin In2S3 nanosheets

• Thin In2S3 nanosheets composed of nanocrystals were prepared by polyol route using PVP.
• Crystallinity and size of the nanosheets were dependent on the PVP concentration.
• Photoresponses were measured on nanostructured pellets by cold pressing nanosheets.
• Devices showed enhanced photoconductivity and photoswitching behavior.
• Plausible mechanisms were suggested.

In2S3 nanosheets were synthesized using a low temperature tetraethyleneglycol (TEG) mediated polyol route and polyvinylpyrrolidone (PVP) as the capping agent. Thin In2S3 nanosheet of thickness of 8–10 nm was obtained under optimized PVP concentration of 0.5 g. The thin nanosheets were formed of 10 nm sized crystalline tetragonal-shaped In2S3 nanocrystals assemblying into the nanosheet structures. The dimensions and the crystallinity of the nanosheets were dependent on the concentration of the PVP in the reaction medium. The nanosheets were cold-pressed into dense nanostructured pellets to measure their room temperature on-the-surface photoresponse characteristics. The nanostructured devices showed enhancement in conductivity under light as compared to that in the dark and demonstrated photoswitching behavior. Superior electrical conductivity (144% higher) and higher life time of free carriers (20.9 ± 2.5 s) observed from the optimized sample suggested its application as a low-cost photodetector.

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