Preparation and excitation power-dependent photoluminescence of tetrapod-quantum wells

Abstract

Tetrapod-quantum well (TW) with CdSe core and quantum wells in gradient alloyed CdSeS arms was synthesized using the one-pot colloidal method. The morphology, crystal structure, UV–vis absorption, photoluminescence (PL), and excitation power-dependent PL properties of TWs prepared within a 30 min reaction time were investigated. Their PL spectrum exhibited two emission peaks centered at 2.187 eV and 2.207 eV due to radiative transitions within the core and quantum wells, respectively. Analysis of the excitation power-dependent PL spectra showed that the core and quantum wells’ radiative recombination channels are independent up to the excitation power density of 2.29 × 10² mW cm⁻². At higher power densities, efficient carrier transfer from the quantum wells into the cores occurred. This can be explained by the state filling of quantum wells and the decreasing band gap energy of gradient alloyed CdSeS arms towards the CdSe core. This study demonstrates a simple, green, and cost-effective approach for synthesizing one-color and two-color tetrapods based on CdSe and CdSeS materials, as well as the recovery process in nanostructures with two emission channels under various excitation conditions. The results could help to design and prepare white-light-emitting tetrapod-double quantum wells for efficient light-emitting applications.