Size Dependent Optical Properties of CdSe Nanocrystals at Low Temperature

Abstract

In this work, we demonstrate that the optical properties of CdSe nanocrystals (NCs) show a strong size dependence at low temperature (~10 K). The photoluminescence (PL) peak is shifted to higher energies as the growth time of synthesized CdSe NCs decreases, which can be attributed to size differences of CdSe NCs. The power-dependent PL measurements, where the PL intensities are linearly increased as a function of laser excitation powers were performed. These linearly increased PL intensities support the excitonic properties of confined states in CdSe NCs. In addition, the carrier dynamics of CdSe NCs are observed using time-resolved PL measurements. The carrier decay times are increased as the sizes of CdSe NCs are increased.

Colloidal semiconductor nanocrystals: from bottom-up nanoarchitectonics to energy harvesting applications

“…1,65 It was observed that by tuning the size of CdSe NCs, the optical response can be achieved in the range of 400–600 nm. 50 Kim et al developed a full-color visible photodetector using Sn 2 S 6 4− ligand-capped CdSe NCs. 295 The photodetector device was prepared by integrating different-sized Sn 2 S 6 4− -capped CdSe NCs with indium–gallium–zinc-oxide.…”

“…49 For example, size-dependent CdSe NCs show photoluminescence (PL) over the entire visible wavelength; however, they are limited in the near-infrared (NIR) region. 50 However, alloyed CdSe x Te 1− x NCs efficiently emit light in the NIR spectral range. 51 Highly stable Zn x Cd 1− x Se-alloyed NCs emit blue light with excellent efficiency.…”