Activating Carrier Multiplication in PbSe Quantum Dot Solids by Infilling with Atomic Layer Deposition
Sybren Ten Cate1, Yao Liu2, C S Suchand Sandeep1
1†Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
The Journal of Physical Chemistry Letters
|August 19, 2015
Summary
Carrier multiplication, generating multiple electron-hole pairs per photon, is key for efficient photovoltaics. Infilling PbSe quantum dots with metal oxides enables this phenomenon, boosting solar cell potential.
Area of Science:
- Materials Science
- Nanotechnology
- Photovoltaics
Background:
- Carrier multiplication enhances photovoltaic efficiency by generating multiple charge carriers from a single photon.
- PbSe quantum dots are promising materials for photovoltaics due to their tunable bandgaps.
Purpose of the Study:
- To investigate the impact of metal oxide infilling on carrier multiplication in PbSe quantum dot solids.
- To explore the potential of atomic layer deposition for enhancing photovoltaic performance.
Main Methods:
- Atomic layer deposition (ALD) was used to infill PbSe quantum dot solids with Al2O3 and Al2O3/ZnO.
- Time-resolved microwave conductivity (TRMC) measurements were employed to assess carrier multiplication.
Main Results:
- Carrier multiplication was observed in 1,2-ethanedithiol-linked PbSe quantum dot solids infilled with Al2O3 or Al2O3/ZnO.
- Infilled films exhibited carrier multiplication efficiencies comparable to solution-dispersed PbSe quantum dots.
- Carrier multiplication was negligible in noninfilled PbSe quantum dot films.
Conclusions:
- Metal oxide infilling via ALD effectively enables carrier multiplication in PbSe quantum dot solids.
- This approach significantly enhances the potential for developing highly efficient photovoltaics.
- Auger recombination does not significantly limit the carrier multiplication efficiency in these infilled systems.
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