Ultrafast carrier dynamics and nonlinear optical absorption of two-dimensional CuCrP₂S₆ nanosheets

Layered metal thiophosphates exhibit exceptional physical properties and hold significant potential for optoelectronic applications. Investigating their optical properties and photoexcited carrier dynamics is essential for device design. However, the optical and electronic properties of CuCrP₂S₆ (CCPS), a member of this material family, remain insufficiently understood, limiting its practical development. This study focuses on the nonlinear optical properties and ultrafast dynamics of CCPS nanosheets. I-scan measurements reveal a pronounced two-photon absorption (TPA) effect. Furthermore, pump-probe experiments combined with broadband transient absorption spectroscopy provide detailed insights into carrier dynamics, identifying a fast relaxation process dominated by carrier-carrier scattering and a slower relaxation process influenced by phonon-assisted interactions. These findings not only deepen our understanding of CCPS nanosheets but also pave the way for their application in ultrafast optics and multifunctional optoelectronic devices, as demonstrated by our proposed CCPS-based all-optical switch.