Back to Search
Start Over
Auger Up-Conversion of Low-Intensity Infrared Light in Engineered Quantum Dots
- Source :
- ACS nano. 10(12)
- Publication Year :
- 2016
-
Abstract
- One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. Here we show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. This process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. Compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the "productive" Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.
- Subjects :
- Physics
Auger effect
business.industry
General Engineering
General Physics and Astronomy
Heterojunction
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
Two-photon absorption
0104 chemical sciences
Multiple exciton generation
symbols.namesake
Quantum dot
symbols
Optoelectronics
General Materials Science
Trion
0210 nano-technology
business
Absorption (electromagnetic radiation)
Biexciton
Subjects
Details
- ISSN :
- 1936086X
- Volume :
- 10
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- ACS nano
- Accession number :
- edsair.doi.dedup.....902506abf576f8377b8f5c32c7979cb2