Light-induced charged and trap states in colloidal nanocrystals detected by variable pulse rate photoluminescence spectroscopy.

Intensity instabilities are a common trademark of the photoluminescence of nanoemitters. This general behavior is commonly attributed to random fluctuations of free charges and activation of charge traps reducing the emission yield intermittently. However, the actual physical origin of this phenomenon is actively debated.

The temperature dependence of Cr3+:YAG zero-phonon lines.

This paper deals with the photoluminescence temperature dependence of the zero-phonon lines of Cr(3+) ions in an yttrium aluminium garnet (YAG) matrix. Experimental data were analysed in the framework of electron-phonon coupling in the quadratic approximation and it was found that Cr(3+) ions in the YAG matrix are strongly coupled with lattice vibrations, with a Debye temperature of about 550 K and a value of the quadratic coupling constant of 0.65.

Charged excitons, Auger recombination and optical gain in CdSe/CdS nanocrystals.

CdSe/CdS colloidal nanocrystals are members of a novel class of light-emitting nanoparticles with remarkable optical properties such as suppressed fluorescence blinking and enhanced emission from multiexciton states. These properties have been linked to the suppression of non-radiative Auger recombination. In this work we employ ultrafast spectroscopy techniques to identify optical signatures of neutral and charged excitonic and multiexcitonic states.

Exciton-Exciton Interaction and Optical Gain in Colloidal CdSe/CdS Dot/Rod Nanocrystals.

Exciton-exciton interaction in dot/rod CdSe/CdS nanocrystals has proved to be very sensitive to the shape of nanocrystals, due to the unique band alignment between CdSe and CdS. Repulsive exciton-exciton interaction is demonstrated, which makes CdSe/CdS dot/rods promising gain media for solution-processable lasers, with projected pump threshold densities below 1 kW cm(-2) for continuous wave lasing.