High photoluminescence quantum efficiency in near infrared of CdS nanocrystals in glass phosphate matrix

Abstract

In this work measurements of photoluminescence quantum efficiency (η) in CdS nanocrystals embedded in phosphate glass matrix was performed using the thermal lens technique. The study was performed, using two different excitation wavelengths, in three samples with average sizes of 5.1, 6.3 and 6.7 nm and emission around 980 nm. The emission was strongly dominated by surface trap states. The photoluminescence quantum efficiency obtained was up to 60% for the smallest nanocrystals. It was also observed that η is independent of the excitation wavelength for each nanocrystal.