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

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 (4–300K). The authors show that the linewidth of the dot PL emission is strongly enhanced at temperatures above 150K. 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.