Ultra Efficient Quantum Ratchet Solar Cells

Lead Research Organisation: Imperial College London
Department Name: Dept of Physics


The efficiency of a solar cell can be significantly augmented if sequential
absorption of photons can be achieved. This can both increase the spectral
range over which a solar cell can absorb and reduce the quantity of energy
lost as parasitic heat generation within the solar cell. We have recently
proposed a means by which sequential absorption can be promoted in
semiconductor quantum heterostructures . The PhD project aims to
demonstrate this new type of solar cell experimentally.
M. Yoshida, N. J. Ekins-Daukes, D. J. Farrell, and C. C. Phillips, Applied Physics Letters 100, 263902 (2012).
Okada, Y. et al., Intermediate band solar cells: Recent progress and future directions. Applied Physics Reviews, 2(2), p.021302.( 2015)
Curtin, O.J. et al.,Photovoltaics, IEEE Journal of, 6(3), pp.673-678.(2016)
Pusch, A. et al.. Progress in Photovoltaics Research and Applications
, 24(5), pp.656 (2016)


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509486/1 01/10/2016 31/03/2022
1992406 Studentship EP/N509486/1 01/10/2017 30/09/2021 Kenneth Maxwell Hughes
Description My research is focussed on testing nanostructure devices that have had small changes made to the design of the first working prototype. Each change has been implemented to target a particular problem with the first device (e.g. only operating at very low temperatures).

One of the new devices has been found to exhibit a plateau in the photocurrent within a particular bias range, which indicates that charge carriers are getting trapped by the ratchet mechanism, and should be able to absorb a second sub-bandgap photon for sequential absorption. It is this sequential absorption - the search for which is ongoing - that we are looking to prove, and the details of it are to be compared to the previous device. This already tells us that the changes made to this device (increased in-built electric field across the junction) have not prevented the mechanism from functioning, but the details of the effect on the two-photon signal are yet to be determined.
Exploitation Route Further experiments are to be performed on this device and on then on other new designs. All the results are then to be compared and critiqued in order to determine what changes to the designs were beneficial, and how they can be improved. There should then be further designs made and submitted for fabrication, in order to further refine and improve these devices towards the end goal of a viable, working ultra-efficient solar panel.
Sectors Energy,Environment