Abstract
Practical Concept of an All-Optical Hot Carrier Solar Cell
D. König, Y. Yao, and J. Yang
Australian Centre of Advanced Photovoltaics (ACAP), University of New South Wales, Sydney 2052, Australia
The all-optical hot carrier solar cell (aoHCSC) [1] is an intriguing device concept avoiding HC cooling by feeding HCs into local radiative recombination centers. These have transition energies above the HC absorber (HCA) bandgap and are located within the HCA to match the HC ballistic mean free path (lmfp), suppressing HC cooling as major loss mechanism. HC energy extraction proceeds via photon emission. We propose a practical concept of the aoHC energy converter (aoHCEC) which feeds into conventional solar cells with bandgaps matching emitted photons. With existing materials, the concept builds upon waveguides within a HCA made of highly polar direct bandgap material to promote radiative carrier recombination. The horizontal arrangement of anti-nanowire (aNW) arrays as waveguides and radiative recombination sites results in a lateral energy extraction by photon (hν) flux of secondary hν. This arrangement can concentrate the initial (solar) hν flux by factors of 103 to 104, feeding two micro-solar cells at the aoHCEC edges where aNWs terminate. This concentration process originates from HC radiative recombination and is therefore indirect, hence independent of direction and focus of solar irradiation and only depends on the absolute solar hν flux: solar tracking is not required and diffuse light can be converted. HC cooling is minimized by inter-aNW distances of ≤ 1.5 lmfp (≈30 nm, T = 300 K, III-Vs). Together with the HC energy extracted by hν, this lifts size constraints of aoHCECs occuring for HCSCs due to HC extraction and associated issues of elastic HC scattering, HC cooling and ballistic transport [2]. Thus, aoHCECs can be macroscopic (several μm thick, active area in cm2 range). High indirect concentration ratios and small sizes of solar cells at the oaHCEC edges allow for sophisticated III-V technologies to be applied on an economic scale. High accuracy density functional theory (HSE06) yielded necessary material data and were verified with availa-ble experimental data (InxGa1-xN, x= 0.38, and BSb). We will present latest results at the 6 World PVSEC.
[1] D.J. Farrell et al., Appl. Phys. Lett. 99, 111102 (2011).
[2] D. König et al., Jap. J. Appl. Phys. 53, 05FV04 (2014)
[3] S. Dalui et al., J. Cryst. Growth 305 (2007) 149; Y. Yao et al., So-lar Energy Mater. Sol. Cells 111 (2013) 123
[4] A. Le Bris et al.. Appl. Phys. Lett. 97, 113506 (2010)
D. König, Y. Yao, and J. Yang
Australian Centre of Advanced Photovoltaics (ACAP), University of New South Wales, Sydney 2052, Australia
The all-optical hot carrier solar cell (aoHCSC) [1] is an intriguing device concept avoiding HC cooling by feeding HCs into local radiative recombination centers. These have transition energies above the HC absorber (HCA) bandgap and are located within the HCA to match the HC ballistic mean free path (lmfp), suppressing HC cooling as major loss mechanism. HC energy extraction proceeds via photon emission. We propose a practical concept of the aoHC energy converter (aoHCEC) which feeds into conventional solar cells with bandgaps matching emitted photons. With existing materials, the concept builds upon waveguides within a HCA made of highly polar direct bandgap material to promote radiative carrier recombination. The horizontal arrangement of anti-nanowire (aNW) arrays as waveguides and radiative recombination sites results in a lateral energy extraction by photon (hν) flux of secondary hν. This arrangement can concentrate the initial (solar) hν flux by factors of 103 to 104, feeding two micro-solar cells at the aoHCEC edges where aNWs terminate. This concentration process originates from HC radiative recombination and is therefore indirect, hence independent of direction and focus of solar irradiation and only depends on the absolute solar hν flux: solar tracking is not required and diffuse light can be converted. HC cooling is minimized by inter-aNW distances of ≤ 1.5 lmfp (≈30 nm, T = 300 K, III-Vs). Together with the HC energy extracted by hν, this lifts size constraints of aoHCECs occuring for HCSCs due to HC extraction and associated issues of elastic HC scattering, HC cooling and ballistic transport [2]. Thus, aoHCECs can be macroscopic (several μm thick, active area in cm2 range). High indirect concentration ratios and small sizes of solar cells at the oaHCEC edges allow for sophisticated III-V technologies to be applied on an economic scale. High accuracy density functional theory (HSE06) yielded necessary material data and were verified with availa-ble experimental data (InxGa1-xN, x= 0.38, and BSb). We will present latest results at the 6 World PVSEC.
[1] D.J. Farrell et al., Appl. Phys. Lett. 99, 111102 (2011).
[2] D. König et al., Jap. J. Appl. Phys. 53, 05FV04 (2014)
[3] S. Dalui et al., J. Cryst. Growth 305 (2007) 149; Y. Yao et al., So-lar Energy Mater. Sol. Cells 111 (2013) 123
[4] A. Le Bris et al.. Appl. Phys. Lett. 97, 113506 (2010)
| Original language | English |
|---|---|
| Publication status | Published - 27 Nov 2014 |
| Externally published | Yes |