Solar Energy Conversion Using Artificial Atoms, Molecules and Solids
Author(s)
Lian, Tianquan (Tim)
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Abstract
Quantum confined semiconductor nanocrystals have emerged as a new class of
light harvesting and charge separation materials in photovoltaic and
photocatalyticdevices. Compared with single component quantum dots (or
“artificial atoms”), semiconductor nanoheterostructures (or “artificial
molecules”), consisting of two or more component materials, offer
additional opportunities to control charge separation properties by tailoring
their compositions and dimensions through wavefunction engineering. With
(quasi-) type II band alignment, both fast forward charge transfer (charge
separation and hole filling) and slow backward recombination (charge
recombination and exciton-exciton annihilation) can be achieved, enhancing
the charge separation efficiency. Near-unity quantum yield of redox mediator
(methylviologen radical) generation can be obtained in asymmetric CdSe/CdS
dot-in-rod nano-heterostructures. When coupled with catalysts (Pt), these
nanorods led to a much higher solar-driven hydrogen generation efficiency
compared to molecular dyes and other nanocrystals. Quantum dots can also form
“Artificial solid”
electrodes with high carrier mobility and strong quantum confinement effect,
enabling their integration into photoelectrochemical water splitting devices.
In this talk, we will discuss how the fundamental charge transfer dynamics in
these nanostructures can be directly probed by time-resolved spectroscopy and
used to guide the design and optimization of nanoheterostructures for
efficient light-driven H2 generation.
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Date
2014-10-15
Extent
53:09 minutes
Resource Type
Moving Image
Resource Subtype
Lecture