Temperature dependence of the photoluminescence emission from thiol-capped PbS quantum dots

Abstract

The authors report the temperature dependence of the near-infrared photoluminescence (PL) emission from thiol-capped PbS quantum dots. The high thermal stability of the PL allows the authors to study the thermal broadening of the dot emission over an extended temperature range $(4–300\mathrm{K})$ . The authors show that the linewidth of the dot PL emission is strongly enhanced at temperatures above $150\mathrm{K}$ . This behavior is attributed to dephasing of the quantum electronic states by carrier interaction with longitudinal optical phonons. The authors’ data also indicate that the strength of the carrier-phonon coupling is larger in smaller dots.