Temperature behavior of the Optical Absorption and Photoluminescence Spectra of InP/ZnS Nanocrystals with a Stabilizing Polyvinylpyrrolidone-based Coating

TL;DR

This study investigates how temperature affects the optical absorption and photoluminescence of InP/ZnS nanocrystals stabilized with a polyvinylpyrrolidone coating, revealing size distribution effects and temperature-dependent emission stability.

Contribution

It provides new insights into the temperature-dependent optical behavior of InP/ZnS nanocrystals with a PVP-based stabilizer, highlighting the influence of shell thickness and defect states.

Findings

Inhomogeneous broadening linked to size distribution.

Temperature shift due to interaction with acoustic phonons.

Luminescence quenching related to dangling bonds at the core-shell interface.

Abstract

The present paper deals with the results of a research work on the optical properties of colloidal InP/ZnS nanocrystals stabilized with a heterobifunctional polyvinylpyrrolidone polymer. We have analyzed the absorption and photoluminescence spectra of the samples as solutions with various concentrations and deposited films, as well as the patterns of their temperature changes in the range of 6.5 - 296 K. An inhomogeneous broadening of exciton optical bands has been observed to be related to a wide distribution of nanocrystals in size. A temperature shift of the exciton absorption and emission maxima has been found to be due to the interaction with acoustic phonons. It has been shown that the quenching of defect-related luminescence is carried out through local energy levels of dangling bonds of phosphorus atoms involved at the core-shell interface, and the temperature stability of exciton emission is determined by the thickness of the ZnS shell.