Two-dimensional CdX (X=Se, Te) nanosheets controlled synthesis and their photoluminescence properties
Two-dimensional (2D) CdX (X=Se, Te) nanosheets are one of potentiol candidates for novel optoelectronic applications. Herein, the Oleic Acid (OA), Stearic Acid (SA) and typical Cd precursor were chosed to synthesize high quality 2D CdX nanosheets. Their unique absorption (or excitation) and photoluminescence (PL) properties have been studied. The PL profiles are differentiated as band-edge and trap-states PL. These strap-states emanated from the intrinsic surface defect sites (Cd2+ or Se2-). The intrinsic defect sites generated because of the bonding termination at the surface of the nanosheets. A complex formed by the Cd-interstitial (Cdi-VCd) acts as a donor-acceptor pair according to Prener-Williams model and accountable for large Stokes-shifted trap-states PL peak. Our experimental findings imply that these surface trap-states follow the Configurational-Coordinates model. Inevitably, the PL dynamics of CdSe nanosheets strongly depend on the surface trap-states in addition to their size and shape.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry C HOT Papers