Luminescence of colloidal CdSe/ZnS nanoparticles: high sensitivity to solvent phase transitions
1 Electrical Engineering Department, University at Buffalo, Buffalo, NY 14260, USA
2 Chemical and Biological Engineering Department, University at Buffalo, Buffalo, NY 14260, USA
Nanoscale Research Letters 2011, 6:142 doi:10.1186/1556-276X-6-142Published: 14 February 2011
We investigate nanosecond photoluminescence processes in colloidal core/shell CdSe/ZnS nanoparticles dissolved in water and found strong sensitivity of luminescence to the solvent state. Several pronounced changes have been observed in the narrow temperature interval near the water melting point. First of all, the luminescence intensity substantially (approximately 50%) increases near the transition. In a large temperature scale, the energy peak of the photoluminescence decreases with temperature due to temperature dependence of the energy gap. Near the melting point, the peak shows N-type dependence with the maximal changes of approximately 30 meV. The line width increases with temperature and also shows N-type dependence near the melting point. The observed effects are associated with the reconstruction of ligands near the ice/water phase transition.