Room temperature single photon emission of colloidal quantum dots at 800nm

Abstract

Single photon emission at 800 nm from single colloidal quantum dots on a sapphire substrate at room temperature was studied. The fluorescence lifetime, blinking phenomenon and anti-bunching effect of the 800nm colloidal quantum dots were measured, and the second order correlation function g2(0)≈0.035 was obtained, indicating that quantum dots with a center wavelength of 800nm were pure and high-quality single photon sources. It was found that the excitation power had a great influence on the purity of single photon source from the single quantum dots. High laser excitation power would cause the 800nm quantum dots not only exciton emission, but also bi-excitons emission or multi-excitons emission, Accompanying by an increase in the Auger non-radiative recombination and a decrease in the quantum yield. Therefore, it is important to excite the 800nm single quantum dots with proper excitation power.