# High efficiency carrier multiplication in PbSe nanocrystals: implications for solar energy conversion.

@article{Schaller2004HighEC, title={High efficiency carrier multiplication in PbSe nanocrystals: implications for solar energy conversion.}, author={Richard D. Schaller and Victor I. Klimov}, journal={Physical review letters}, year={2004}, volume={92 18}, pages={ 186601 } }

We demonstrate for the first time that impact ionization (II) (the inverse of Auger recombination) occurs with very high efficiency in semiconductor nanocrystals (NCs). Interband optical excitation of PbSe NCs at low pump intensities, for which less than one exciton is initially generated per NC on average, results in the formation of two or more excitons (carrier multiplication) when pump photon energies are more than 3 times the NC band gap energy. The generation of multiexcitons from a…

## 1,485 Citations

Effect of electronic structure on carrier multiplication efficiency: Comparative study of PbSe and CdSe nanocrystals

- Materials Science
- 2005

Recently, we demonstrated that PbSe nanocrystal quantum dots can efficiently produce multiple electron-hole pairs (excitons) in response to a single absorbed photon. To address the generality of this…

Carrier Multiplication and Its Reduction by Photodoping in Colloidal InAs Quantum Dots: Addition/correction

- Physics
- 2008

Carrier (exciton) multiplication in colloidal InAs/CdSe/ZnSe core−shell quantum dots (QDs) is investigated using terahertz time-domain spectroscopy, time-resolved transient absorption, and…

Carrier Multiplication and Its Reduction by Photodoping in Colloidal InAs Quantum Dots

- Physics
- 2007

Carrier (exciton) multiplication in colloidal InAs/CdSe/ZnSe core−shell quantum dots (QDs) is investigated using terahertz time-domain spectroscopy, time-resolved transient absorption, and…

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- Materials Science, MedicineNature communications
- 2014

It is demonstrated that thick-shell PbSe/CdSe nanostructures can show almost a fourfold increase in the CM yield over conventional Pb Se quantum dots, accompanied by a considerable reduction of the CM threshold.

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- Chemistry
- 2006

Semiconductor nanocrystals can respond to absorption of a single photon by producing multiple electron-hole pairs with extremely high efficiencies. This letter analyzes the impact of this…

Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation

- Physics
- 2005

Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this…

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- Materials Science, MedicineACS nano
- 2011

Calculations of impact ionization rates, carrier multiplication yields, and solar-power conversion efficiencies in solar cells based on quantum dots (QDs) of a semimetal, α-Sn, and previous ones on PbSe and PbS QDs are presented.

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- Materials Science, EngineeringOPTO
- 2012

While multiple exciton generation (MEG) is known to occur more efficiently in semiconductor nanocrystals than in the bulk, the required energy threshold prevents visible photons from being utilized.…

Enhanced multiple exciton generation in quasi-one-dimensional semiconductors.

- Materials Science, MedicineNano letters
- 2011

A significant enhancement of multiple exciton generation in PbSe quasi-one-dimensional semiconductors (nanorods) over zero-dimensional nanostructures (nanocrystals) is reported, characterized by a 2-fold increase in efficiency and reduction of the threshold energy to (2.23 ± 0.03)E(g), which approaches the theoretical limit of 2E( g).

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- Materials Science, Physics
- 2020

In conventional solar cell semiconductor materials (predominantly Si) photons with energy higher than the band gap initially generate hot electrons and holes, which subsequently cool down to the band…

## References

SHOWING 1-10 OF 35 REFERENCES

Quantum dot solar cells

- Materials Science
- 2002

Abstract Quantum dot (QD) solar cells have the potential to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66% by utilizing hot…

Solar cell efficiency and carrier multiplication in Si1−xGex alloys

- Physics
- 1998

Crystalline Si1−xGex compounds offer the possibility for tuning the electronic energy band structure with the chemical composition of the alloy in order to adapt the material for devices utilizing…

Interband and Intraband Optical Studies of PbSe Colloidal Quantum Dots

- Physics
- 2002

PbSe nanocrystal colloids exhibit a well-defined excitonic structure with the lowest energy exciton tuning from 0.5 to 1 eV, as a function of size. Band-edge fluorescence is observed from 1.2 to 2 μm…

Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Nanocrystals

- Chemistry
- 2000

Femtosecond transient absorption in the visible and infrared spectral ranges has been applied to study carrier dynamics and mechanisms for resonant optical nonlinearities in CdSe nanocrystals (NCs)…

Efficiency of hot-carrier solar energy converters

- Physics
- 1982

A single‐threshold quantum‐utilizing device in which the excited carriers thermally equilibrate among themselves, but not with the environment, can convert solar energy with an efficiency approaching…

Spectroscopy and hot electron relaxation dynamics in semiconductor quantum wells and quantum dots.

- Physics, MedicineAnnual review of physical chemistry
- 2001

The effects of size quantization in semiconductor quantum wells (carrier confinement in one dimension and quantum dots) on the respective carrier relaxation processes are reviewed, with emphasis on electron cooling dynamics.

Tunable near-infrared optical gain and amplified spontaneous emission using PbSe nanocrystals

- Materials Science
- 2003

Here, for the first time, we demonstrate amplified spontaneous emission (ASE) from PbSe nanocrystals (NCs) with emission energies tunable in the near-infrared (IR). We show that despite complications…

Absorption, carrier lifetime, and gain in InAs-GaAs quantum-dot infrared photodetectors

- Materials Science
- 2003

Quantum-dot infrared photodetectors (QDIPs) are being studied extensively for mid-wavelength and long-wavelength infrared detection because they offer normal-incidence, high-temperature,…

Optical gain and stimulated emission in nanocrystal quantum dots.

- Chemistry, MedicineScience
- 2000

This work examined the competing dynamical processes involved in optical amplification and lasing in nanocrystal quantum dots and found that, despite a highly efficient intrinsic nonradiative Auger recombination, large optical gain can be developed at the wavelength of the emitting transition for close-packed solids of these dots.

Auger ionization of semiconductor quantum drops in a glass matrix

- Chemistry
- 1990

Abstract A microscopic model of degradation of both the nonlinear optical and luminescent properties of semiconductor-doped glasses is proposed. In the framework of the model the degradation is due…