Tunable, Bright, and Narrow-Band Luminescence from Colloidal Indium Phosphide Quantum Dots

Abstract

Synthesis of cadmium (Cd)-free quantum dots (QDs) with tunable emission and high color purity has been a big challenge for the academic and industrial research community. Among various Cd-free QDs, indium phosphide (InP) QDs exhibit reasonably good color purity with emission full width at half-maximum (fwhm) values between 45 and 50 nm for green and over 50 nm for red emission, which is not good enough, as values less than 35 nm are favorable in commercial display products. In this work, we present the synthesis of highly luminescent In(Zn)P/ZnSe/ZnS QDs with tunable emission from 488 to 641 nm and high color purity. We found that the addition of zinc during the conventional SILAR growth of shell (ZnSe or ZnS) deteriorated the absorption features of core InP QDs and resulted in broader emission line widths. We solved this issue by synthesizing Zn carboxylate covered In(Zn)P QDs in a single step and dramatically decreased the emission fwhm to as low as 36 nm with quantum yields (QYs) up to 67% for the gree...