| Nov 22, 2011 |
Colloidal quantum dot photovoltaics: A path forward
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(Nanowerk News) Colloidal quantum dots (CQDs) offer a path toward high-efficiency photovoltaics
based on low-cost materials and processes. Spectral tunability via the quantum size effect facilitates
absorption of specific wavelengths from across the sun's broad spectrum.
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CQD materials' ease of
processing derives from their synthesis, storage, and processing in solution. Rapid advances have
brought colloidal quantum dot photovoltaic solar power conversion efficiencies of 6% in the latest
reports.
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These achievements represent important first steps toward commercially compelling
performance.
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In a recent review in ACS Nano ("Colloidal Quantum Dot Photovoltaics: A Path Forward"), Illan Kramer and Ted Sargent take a look at advances in device architecture and materials science.
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They diagnose the principal phenomenon – electronic states within the CQD film band gap that limit both current
and voltage in devices – that must be cured for CQD PV devices to fulfill their promise.
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They close with
a prescription, expressed as bounds on the density and energy of electronic states within the CQD
film band gap, that should allow device efficiencies to rise to those required for the future of the
solar energy field.
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