The photoconductive properties of nanocrystal solids have so far been described by an empirical model based on phenomenological parameters such as sheet resistance and voltage barrier or by a microscopic approach that considered the local exciton ionization but disregarded the transport pathway needed to harvest the charges. Here, we have studied the photocurrent in thin films of densely packed nanocrystals using scanning photocurrent microscopy with a spatial resolution of 200 nm, and we present a microscopic model to fit our data that includes both the exciton ionization process and the influence of the charge transport pathway of the photoexcited charges. With this theoretical framework, physical parameters such as the product of mobility and lifetime of the charge carriers in the nanocrystal film can be assessed.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 14 2012|
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials