Colossal photo-conductive gain in low temperature processed TiO2 films and their application in quantum dot solar cells

TitleColossal photo-conductive gain in low temperature processed TiO2 films and their application in quantum dot solar cells
Publication TypeJournal Article
Year of Publication2017
AuthorsMandal, D, Goswami, PN, Rath, AK
JournalApplied Physics Letters
Volume110
Issue12
PaginationArticle Number: 123902
Date PublishedMAR
AbstractColloidal quantum dot (QD) solar cells have seen remarkable progress in recent past to reach the certified efficiency of 10.6%. Anatase titanium oxide (TiO2) is a widely studied n-type widow layer for the collection of photogenerated electrons in QD solar cells. Requirement of high temperature (similar to 500 degrees C) processing steps proved to be disadvantageous for its applications in flexible solar cells and roll to roll processing, and it also has adverse commercial implications. Here, we report that solar light exposure to low temperature processed (80 degrees C-150 degrees C) TiO2 and niobium doped TiO2 films leads to unprecedented enhancement in their electron densities and electron mobilities, which enables them to be used as efficient n-type layers in quantum dot solar cells. Such photoinduced high conducting states in these films show gradual decay over hours after the light bias is taken off and can be retrieved under solar illumination. On the contrary, TiO2 films processed at 500 degrees C show marginal photo induced enhancements in their characteristics. In bilayer configuration with PbS QDs, photovoltaic devices based on low temperature processed TiO2 films show improved performance over high temperature processed TiO2 films. The stability of photovoltaic devices also improved in low temperature processed TiO2 films under ambient working conditions. Published by AIP Publishing.
DOI10.1063/1.4978766
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)3.142
Divison category: 
Physical and Materials Chemistry

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