Controlling opto-electronic characteristics of ternary II-VI alloyed quantum dots: Alcohol processing assay

Abstract

For their ultra-wide color gamut, high efficiency, robustness, and solution processability, Cd-based alloy semiconductor quantum dots (AQDs) continue to proliferate by driving innovations in the fields of optoelectronics, photovoltaics, multiplex bio-imaging, and cancer research. Herein, non-toxic, low-cost isopropyl alcohol vapor-based oxidative treatment protocol is developed and applied to tune the light emission spectrum of crystalline core-shell CdSe1-xSx/ZnS quantum dots. As evidenced by the results of structural investigations, these AQDs when exposed to vapors produced ultrasonically from 10:1 isopropyl alcohol-to-water mix undergo an isotropic, diameter non-specific size reduction at the rate of ∼1.3 Å min-1. Nonlinear time-dependent spectral shifts, revealed experimentally, are consistent with the results of the effective-mass approximation treatment. The emission yields are seen to undergo an initial drop, yet to plateau as the etch time increases. The study opens a door to a soft, top-down monotonic tailoring of the light emission characteristics and opto-electronic response of stoichiometrically- and hierarchically-complex core-shell constructs in technologically-viable group II-VI nano-semiconductors as well as AQD-based catalytic conversion of organic compounds.