Photoinduced band filling in strongly confined colloidal PbS quantum dots

Increase in continuous wave laser excitation (6 W/cm2 to 120 W/cm2) of colloidal PbS quantum dots in the strongly quantized regime (diameters 2.0 nm and 4.7 nm) deposited on semi-insulating GaAs and glass causes a clear blue shift (0.019 eV and 0.080 eV) of the emission spectra. Proof of the applicability of a dynamic three-dimensional band filling model is the significance of the presented results and demonstrates the effective electronic coupling in quantum dot arrays similar to superlattices. The work also reveals the influence of quantum dot sizes on photo-doping effects.