Significant Enhancement of Optoelectronic Properties in CuInP₂S₆ via Pressure-Induced Structural Phase Transition

Abstract

Quaternary layered transition metal thiophosphate CuInP2S6 (CIPS) has attracted extensive research interest because of its outstanding optical and ferroelectric properties. Pressure-tuned phase transition is an efficient method to regulate the properties of functional materials in situ, yet there is still much to explore. Herein, we studied the pressure-regulated optoelectronic properties of CIPS and found a four-stage evolution of photoresponsivity under compression. The photoresponse of CIPS barely changes with pressure initially but increases dramatically above 4.2 GPa. Under further compression, the photoresponse first shows a decrease above 7.5 GPa and then a significant increase up to 23.5 GPa. Remarkably, the photoresponse at the highest pressure enhances by two orders of magnitude compared with the starting value. To investigate the origin of these abnormal variations in CIPS, high-pressure UV–vis absorption, Raman, and XRD measurements were conducted and a phase transition from Cc to P3̅1m symmetry was found at approximately 4.0 GPa. We suggest that the pressure-modulated optoelectronic properties in CIPS are closely related to the conductivity change of CIPS caused by its structural phase transition. Our study spotlights the outstanding pressure regulation of optoelectronic properties in CIPS, which paves the way for modifying the behavior of other optoelectronic materials.

Significant Pressure-Enhanced Photoelectric Properties and Extended Spectral Response Range in Zn-Based Chalcopyrite ZnGeP2

“…Pressure, as a fundamental thermodynamic parameter, has been viewed as an effective means to regulate the physical and chemical properties of materials without introducing impurities. − Based on the pressure strategy, extensive research studies on the fundamental properties of materials have been reported, including pressure-induced phase transition, metallization, and pressure-enhanced photoluminescence, superconductivity, and photocurrents. − It has been reported that the optical properties of ZnSiP 2 can be significantly regulated by external pressure, as well as an emergent superconductivity occurs at 24.6 GPa . Lattice dynamical calculations indicated that ZnSnP 2 undergoes an order–disorder transition at around 6.5 GPa .…”