Intrinsic Trade-off between Up-Conversion and Trapping Rates in InAs Quantum Dots for Intermediate-Band Solar Cells

Tex, David M.; Akahane, Kouichi; Kanemitsu, Yoshihiko

doi:10.1103/physrevapplied.6.044003

Cited by 6 publications

(1 citation statement)

References 50 publications

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“…In a certain case, this WL is 2 nm-thick. In the literature, these zones with thicker WL are referred to as 'nanodisks' or 'quantum-well islands' (QWIs) [22,23]. The averaged height, diameter, and density of the QDs were estimated to be 2.5 nm, 18 nm, and 7×10 10 cm −2 , respectively.…”

Section: Quantum Dot Characteristicsmentioning

confidence: 99%

A hot-carrier assisted InAs/AlGaAs quantum-dot intermediate-band solar cell

Behaghel

Tamaki

Chen

et al. 2019

Semicond. Sci. Technol.

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The intermediate-band assisted hot-carrier solar cell (IB-HCSC) concept has been proposed in order to assist the extraction of hot carriers from an absorber that has an intermediate band (IB).In this study, we used a heterostructure based on ten layers of In(Ga)As quantum dots (QDs) embedded in an Al 0.2 Ga 0.8 As single-junction solar cell designed for an intermediate band solar cell (IBSC). QD-IBSCs have proven to be limited by the thermal escape of photo-carriers from QDs at room temperature. In such cases, fundamental improvements in conversion efficiency are only possible if carriers in the IB are not in thermal equilibrium with either conduction or valence bands. Additionally, the IB-HCSC concept provides a high-efficiency limit and enables us to work with all relaxation mechanisms (thermalization, carrier-carrier scattering, and thermal radiation). Under high irradiation, we confirmed the emergence of a hot carrier population in the QDs, limited mostly by thermionic emission, which assists the IBSC by providing a thermoelectric gain in voltage without hindering the possibility of sequential two-photon absorption. Absolute intensity calibrated photoluminescence spectroscopy indicated that the triggering mechanism happens when the QD ensemble is estimated to have a high carrier concentration that behaves as a metal-like IB. Experimental results suggested that the hot carrier effect also occurred in other solar cells based on quantum heterostructures and directions for improvements of hot-carrier assisted QD-IBSCs are proposed for further efficiency gain in optimized device architectures.

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Section: Quantum Dot Characteristicsmentioning

confidence: 99%

A hot-carrier assisted InAs/AlGaAs quantum-dot intermediate-band solar cell

Behaghel

Tamaki

Chen

et al. 2019

Semicond. Sci. Technol.

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Observation of up-conversion fluorescence from exciplex of m-MTDATA:TPBi blend

Zhou

et al. 2022

Journal of Luminescence

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High saturation intensity in InAs/GaAs quantum dot solar cells and impact on the realization of the intermediate band concept at room-temperature

Dagenais

2017

Applied Physics Letters

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High optical saturation intensity at room temperature is reported for an ensemble of undoped quantum dots. The non-linearity of the light-generated-current under resonant excitation from the valence band to the intermediate band is shown to be made up of two components: a background two-photon absorption term and a resonant optical saturation term. It is argued that the solar intensity is much lower than the saturation intensities involved for the first and second transitions in the intermediate band solar cell under 1-sun illumination and therefore prevents exciting an appreciable amount of population in the terminal level that can be ionized to the continuum and generate an appreciable additional current. This additional current is required for enhancing the energy conversion efficiency of a solar cell based on the intermediate band concept. Operating at cryogenic temperatures leads to a reduction in the saturation intensity but it might not be sufficient for increasing the energy conversion efficiency, unless concentrated sun light, and/or high density of quantum dots, and/or quantum dots with a lifetime more comparable to the radiative lifetime are used. The conclusions of this paper are also expected to apply to other quantum dot systems.

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Intrinsic Trade-off between Up-Conversion and Trapping Rates in InAs Quantum Dots for Intermediate-Band Solar Cells

Cited by 6 publications

References 50 publications

A hot-carrier assisted InAs/AlGaAs quantum-dot intermediate-band solar cell

A hot-carrier assisted InAs/AlGaAs quantum-dot intermediate-band solar cell

Observation of up-conversion fluorescence from exciplex of m-MTDATA:TPBi blend

High saturation intensity in InAs/GaAs quantum dot solar cells and impact on the realization of the intermediate band concept at room-temperature

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