Extremely thin absorber solar cells based on nanostructured semiconductors

Abstract

Extremely thin absorber (eta) solar cells aim to combine the advantages of using very thin, easily and cheaply produced absorber layers on nanostructured substrates with the stability of all-solidstate solar cells using inorganic absorber layers. The concept of using nanostructured substrates originated from the dye-sensitised solar cell, where having a very high surface area allows the use of very thin layers of dye while still absorbing sufficient sunlight. However, both the dye and liquid electrolyte used in these devices demonstrated poor stability, and efforts were made to replace them with very thin inorganic absorber layers and solid state hole collectors respectively. The combination of these concepts -a nanostructured substrate coated with a very thin inorganic absorber and completed with a solid state hole collector -is known as an eta solar cell. This review summarises the development of both the inorganic absorbers and solid state hole collectors in porous TiO 2 and ZnO nanorod based cells, focusing on the material properties and growth/deposition methods. Future possibilities for eta solar cells are discussed, including utilisation of a wider range of materials, synthesis methods and novel materials such as quantum dots to produce tuned band gap and multijunction solar cells.

The Future of Using Earth‐Abundant Elements in Counter Electrodes for Dye‐Sensitized Solar Cells

“…The dye is regenerated by an electron from the redox couple, A/A − , (e.g., iodide/triiodide, I/I 3 − ), which is itself reduced by an electron from the back contact. Reproduced with permission . Copyright 2011, Maney Publishing.…”

Efficiency Records in Mesoscopic Dye‐Sensitized Solar Cells

“…The main differences of ETA DSSCs with respect to thin‐film technology (second generation) arise from their working principles . In the case of thin‐film solar cells the semiconductor material must absorb a large portion of the incident photons in layers of 2–5 µm thick, where charges are photogenerated, and these charges must travel through these layers to reach the contacts.…”

Fabrication and characterization of a nanostructured TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber (eta) solar cell

“…Besides, the optical scattering on the surface of the nanostructured substrate will enhance the optical path of the light inside the absorber material, promoting better photon absorption. This effect is known as light trapping [4]. Due to this design, the use of materials with low electronic quality becomes possible, therefore, low cost materials can be used as absorbers.…”