Greater Efficiency from Less Ordered Solar Cells

Krishna Amin (St Catharine’s). December 2, 2019. 

Cantabrigian researchers have suggested that solar cells can have increased efficiency if their chemical compositions are less ordered.

The work, published in Nature Photonics, comes from an international team of scientists, led by Dr Samuel Stranks and Dr Felix Deschler, with members from the Cavendish Laboratory, Department of Material Sciences and Metallurgy, Department of Earth Sciences and the Department of Chemical Engineering and Biotechnology.

Solar cells are traditionally made of crystalline silicon, but perovskite solar cells have recently emerged as promising alternatives, with efficiencies of above 25%. The lead or tin-based materials are easier to source and manufacture than their silicon predecessors, thus reducing costs and increasing the feasibility of solar cells as an energy source.

Less structurally refined products were found to be further increasing the efficiency of perovskite solar cells by creating pockets which can localise charge, created by either sunlight in a solar cell or electrical currents in an LED. It is then easier to extract that energy from the material.

The localisation of the charge is stabilised by chosen cations in the surrounding material, so next steps for the team involve improving performance through identifying ideal cations, as well as finding the right conditions for taming the ‘chaos’ that lends augmented efficiency. Furthermore, if perovskite solar cells are to become widespread in the future, they will need to reduce their sensitivity to water, a trait for which silicon still holds the advantage.

Their paper:
Feldmann, S., Macpherson, S., Senanayak, S.P. et al. Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence. Nat. Photonics 14, 123–128 (2020).

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