Synthesis of ZnSe and ZnSe:Cu quantum dots by a room temperature photochemical (UV‐assisted) approach using Na₂SeO₃ as Se source and investigating optical properties

Abstract

In this study, ZnSe and ZnSe:Cu quantum dots (QDs) were synthesized using Na SeO as the Se source by a rapid and room temperature photochemical (UV-assisted) approach. Thioglycolic acid (TGA) was employed as the capping agent and UV illumination activated the chemical reactions. Synthesized QDs were successfully characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and UV-visible (UV-vis) spectroscopy, Fourier transform-infrared (FT-IR), and energy dispersive X-ray spectroscopy (EDX). XRD analysis demonstrated the cubic zinc blend phase QDs. TEM images indicated that round-shaped particles were formed, most of which had a diameter of about 4 nm. The band gap of the ZnSe QDs was higher than that for ZnSe in bulk. PL spectra indicated an emission with three peaks related to the excitonic, surface trap states and deep level (DL) states. The band gap and QD emission were tunable only by UV illumination time during synthesis. ZnSe:Cu showed green emission due to transition of electrons from the Conduction band (CB) or surface trap states to the T acceptor levels of Cu . The emission was increased by increasing the Cu ion concentration, such that the optimal value of PL intensity was obtained for the nominal mole ratio of Cu:Zn 1.5%.

ZnSe quantum dots downshifting layer for perovskite solar cells

“…The PL spectrum of QDs is a broad emission spectrum with three peaks located at 400 nm, 435 nm and 460 nm. Such phenomenon had been reported by previous investigation [35] . The first peak at 400 nm is attributed to band gap emission.…”

Hydrothermal Synthesis of Cu0.66‐xZn0.34+xSe Materials and Investigation of Their Structural, Optical, and Magnetic Properties

“…[52] The band at 1645 cm À 1 is attributed to the COO À bonds. [53] Raman spectra represent the structural data about the sample in the form of chemical bonds and atomic rearrangements. The Raman spectra of CuZnSe-1, 2 samples are shown in Figure 2(d).…”

Recent Advances in Colloidal Quantum Dots or Perovskite Quantum Dots as a Luminescent Downshifting Layer Embedded on Solar Cells

“…The uniform size of the QDs was achieved using the HI method, which absorbed significant amounts of UV light and converted it into visible light. The emission spectra contained three different peaks at 400 nm, 435 nm, and 460 nm, which were attributed to the bandgap emission, surface trap state, and deep level state of the QDs, respectively [ 197 ]. The results revealed that the cell with QDs exhibited a PCE of 17.3% as well as better stability compared to the cell without QDs.…”