Highly Photoluminescent InP Based Core Alloy Shell QDs from Air-Stable Precursors: Excitation Wavelength Dependent Photoluminescence Quantum Yield, Photoluminescence Decay Dynamics, and Single Particle Blinking Dynamics

Abstract

InP based quantum dots (QDs) are coming in a big way as an alternative to toxic Cd, or Pb based QDs. Unlike many literature reports in this work, green-yellow-orange-red emitting highly photoluminescent (PLQY as high as 65%) and photostable InP/ZnSeS core/alloy shell quantum dots (CAS QDs) have been synthesized using a less toxic, air-stable aminophosphine precursor (P(DMA)3). Unlike literature predictions in this paper, we show that green-yellow-orange-red emitting InP based alloyed QDs can be prepared with InCl3 only. We report here the hitherto unobserved and quite interesting excitation wavelength dependent PLQY for all of these green-yellow-orange-red emitting InP based CAS QDs. PLQY increases monotonically with increasing excitation wavelength. Significant deviation of the PL excitation spectrum from the absorption spectrum has been observed in the shorter wavelength region. This observation is perhaps because the surface mediated nonradiative pathways predominate over radiative charge carrier recom...