GeSe photovoltaics: doping, interfacial layer and devices

Matthew J Smiles; Thomas P Shalvey; Luke Thomas; Theodore D C Hobson; Leanne A H Jones; Laurie J Phillips; Christopher Don; Thomas Beesley; Pardeep K Thakur; Tien-Lin Lee; Ken Durose; Jonathan D Major; Tim D Veal

doi:10.1039/d2fd00048b

GeSe photovoltaics: doping, interfacial layer and devices

Faraday Discuss. 2022 Oct 28;239(0):250-262. doi: 10.1039/d2fd00048b.

Affiliations

¹ Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool, L69 7ZF, UK. T.Veal@liverpool.ac.uk.
² Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.

PMID: 35848780
DOI: 10.1039/d2fd00048b

Abstract

Germanium selenide (GeSe) bulk crystals, thin films and solar cells are investigated with a focus on acceptor-doping with silver (Ag) and the use of an Sb₂Se₃ interfacial layer. The Ag-doping of GeSe occurred by a stoichiometric melt growth technique that created Ag-doped GeSe bulk crystals. A combination of capacitance voltage measurements, synchrotron radiation photoemission spectroscopy and surface space-charge calculations indicates that Ag-doping increases the hole density from 5.2 × 10¹⁵ cm^-3 to 1.9 × 10¹⁶ cm^-3. The melt-grown material is used as the source for thermally evaporated GeSe films within solar cells. The cell structure with the highest efficiency of 0.260% is FTO/CdS/Sb₂Se₃/undoped-GeSe/Au, compared with solar cells without the Sb₂Se₃ interfacial layer or with the Ag-doped GeSe.