Metastable quantum dot for photoelectric devices via flash-induced one-step sequential self-formation

Abstract

The first metastable phase Ag, ZnS: alpha-In2S3 QDs were synthesized by ultrafast light-material interaction. The multiple irradiation of millisecond flash pulses facilitated thermodynamic non-equilibrium superheating and quenching for metastable QD formation, as well as sequential self-formation of alpha-In2S3 QD nucleation, Ag-doping and ZnS-passivation by photo-responsive ionic kinetics. Upon multiple illumination of flash pulses, the synthesis mechanism of Ag, ZnS: alpha-In2S3 QD was experimentally proved by atomic-resolution transmission electron microscopy (AR-TEM), scanning TEM (STEM) and diverse spectral analysis. To verify the metastable phase QD formation by superheating/quenching in reaction solution, the localized surface plasmon (LSP) properties and instantaneous temperature increment were theoretically calculated using finite-difference time-domain (FDTD) method. Finally, optoelectronic performance and long-term stability of as-synthesized QDs were evaluated by demonstrating the broad wavelength metal-semiconductor-metal (MSM) photoelectric device.