Multifunctional Titanium Oxide Layers in Silicon Heterojunction Solar Cells Formed via Selective Anodization

• Published in: Solar RRL 2023-10, Vol.7 (19)
• Main Authors: Jakob, Leonie, Tutsch, Leonard, Hatt, Thibaud, Westraadt, Johan, Ngongo, Sinoyolo, Glatthaar, Markus, Bivour, Martin, Bartsch, Jonas
• Format: Article
• Language: English
• ISSN: 2367-198X; 2367-198X
• DOI: 10.1002/solr.202300418

Herein, a novel strategy is introduced to reduce the consumption of scarce materials in silicon heterojunction solar cells by combining approaches for Ag replacement in the metallization and a reduction of the indium tin oxide layer thickness: a Ti layer deposited by physical vapor deposition serves both as the contact layer of a copper‐based metallization and after electrochemical oxidation as capping layer enabling the use of a thinner transparent conductive oxide. Further, the TiO x layer can build an encapsulation layer. While oxygen evolution and metal dissolution are found to be critical side reactions, a nonaqueous electrolyte is found in which these reactions can be avoided. The application on silicon heterojunction solar cells shows promising first results, exhibiting a short circuit current density of 35 mA cm − 2 and a cell efficiency of close to 21% despite nonoptimized layer thicknesses.