Pressure-induced photo-responsiveness enhancement and positive–negative switch in Bi2S3

Abstract

Bi2S3 has attracted significant interest due to its unique optical, electrical, and photosensitive properties. The utilization of pressure has been substantiated as a proficient technique in modulating the optoelectronic characteristics of functional materials and has garnered increasing attention. In this work, the photoresponse of Bi2S3 upon compression was systematically investigated in combination with in situ photocurrent measurements, Raman spectroscopy, absorption spectroscopy, and density functional theory calculations. Under pressure, Bi2S3 exhibits two distinct photoresponses. Bi2S3 exhibits an obvious positive photoresponse in the pressure range from 0.5 to 9.7 GPa. The photocurrent shows a rapid increase with increasing pressure and reaches the maximum value at 4.0 GPa, which is 5.6 times of the initial value. Interestingly, above 30.3 GPa, Bi2S3 shows a negative photocurrent response, which can be attributed to the photothermal effect caused by pressure-induced metallization phase transition. Our findings provide insight into the modulation of the optoelectronic properties of Bi2S3 and offer more possibilities in the further optimizing design optoelectronic devices based on Bi2S3.