Colloidal Synthesis, Optical Properties, and Hole Transport Layer Applications of Cu₂BaSnS₄ (CBTS) Nanocrystals

Cu2BaSnS4 (CBTS) is an emerging earth-abundant and environmentally benign semiconductor. However, there has been no prior report of colloidal CBTS nanocrystals. Here we developed a colloidal synthesis of CBTS nanocrystals by rational design. Photophysical properties of these nanocrystals are elucidated using photoluminescence and ultrafast transient absorption spectroscopy. Finally, thin films of CBTS nanocrystals grown at room temperature are used as the hole transport layer (HTL) in an organic photodiode yielding a high peak specific detectivity (>3.2 × 1012 Jones) with low noise equivalent power (9.20 × 10–14 W Hz0.5). These results suggest that our colloidal CBTS nanocrystals have potential for optoelectronic applications.