Observation of Individual Semiconducting Nanoparticle Collisions by Stochastic Photoelectrochemical Currents
- Ashantha Fernando (1931059)
- Suman Parajuli (1922017)
- Mario A. Alpuche-Aviles (1684888)
DOIAbstract
We describe a method to detect individual semiconducting nanoparticles (NPs) using the photoelectrochemical (PEC) current measured at an ultramicroelectrode (UME). We use photooxidation of MeOH by TiO<sub>2</sub> NPs as a model system of photocatalysis in solution. NPs suspended in MeOH under constant illumination produce valence-band holes that oxidize MeOH. The electrons are collected at the UME, and the current-versus-time data show discrete current changes that are assigned to particle-by-particle interactions of the NPs with the UME. The stepwise changes in the photocurrent denote irreversible attachment of NPs to Pt UMEs (<30 μm diameter). We found that accumulation of electrons in the conduction band by the NPs is not enough to expla...
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