COLL 54 |
| Since stable charge-transfer injection of carriers in colloidal quantum dots was demonstrated, electrochromism, photoluminescence quenching, and conductivity have been observed. Progress in surface chemistry of core/shell colloidal quantum dots, and minimal processing steps have led to bright and nanoporous thin films with the possibility of electrochemical control of the charge filling of the quantum dots. The quantitative charge injection and fast charge transfer in the films, leads to controlled state charging and clean switching of the emissive and absorptive properties of films. This allows basic studies of the role of charge on the photophysics and the charge transfer properties of colloidal quantum dots. A surprising result has been the apparent greater efficiency of higher energy electrons to introduce non-radiative recombination and quench photoluminescence. Charge transfer through the films shows also clear mobility enhancement for higher energy states. Magnetic field has also been observed to influence the transport though plausible mechanism such as spin-blockade and wave-function overlap modifications. There is still a need for brighter, more conductive, ambipolar or more sensitive materials, for which electrochemical studies of these nanoporous quantum dot thin films provide a basic foundation. |
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Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
2:00 PM-5:40 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 226, Oral
Division of Colloid & Surface Chemistry |