Copper thiocyanate (CuSCN) is a transparent, solid p-type semiconductor and a promising candidate material for optoelectronic and photovoltaic applications, including solar cells. In this work, we report a pressure-induced crystal-to-crystal phase transition in CuSCN, followed by subsequent amorphization. Concurrently, a reduction in the band gap is observed without the onset of metallization. Notably, both the structural transformation and band gap tuning remain irreversible upon full decompression. This study demonstrates the effectiveness of pressure as a tool for tuning the structural and optical properties of CuSCN, highlighting its potential for applications in optoelectronic devices.

phase transitions,band gap