Intrinsic vacancy in 2D defective semiconductor In₂S₃ for artificial photonic nociceptor

It is crucial to develop an advanced artificially intelligent optoelectronic information system that accurately simulates photonic nociceptors like the activation process of a human visual nociceptive pathway. Visible light reaches the retina for human visual perception, but its excessive exposure can damage nearby tissues. However, there are relatively few reports on visible light-triggered nociceptors. Here, we introduce a two-dimensional natural defective III-VI semiconductor beta-In2S3 and utilize its broad spectral response, including visible light brought by intrinsic defects, for visible light-triggered artificial photonic nociceptors. The response mode of the device, under visible light excitation, is very similar to that of the human eye. It perfectly reproduces the pain perception characteristics of the human visual system, such as 'threshold,' 'relaxation,' 'no adaptation', and 'sensitization'. Its working principle is attributed to the mechanism of charge trapping associated with the intrinsic vacancies in In2S3 nanosheets. This work provides an attractive material system (intrinsic defective semiconductors) for broadband artificial photonic nociceptors.