Pulsed Laser Deposition of Transparent Conducting Oxides for Efficient Photovoltaics
The PhD defence of Yury Smirnov will take place (partly) online and can be followed by a live stream.
Yury Smirnov is a PhD student in the research group Inorganic Materials Science (IMS). Supervisor is prof.dr.ing. A.J.H.M. Rijnders and co-supervisor is dr. M. Morales Masis both from the Faculty of Science & Technology (S&T).
Solar energy has the potential to play a central role in the future global energy system. It is an essential source of renewable energy which is largely available and ubiquitous in nature. Further decrease in levelized cost of solar energy is driven by the enhancement of the solar cell efficiencies. In their turn, many high-efficiency devices (such as silicon heterojunction (SHJ) or silicon/halide perovskite tandem solar cells) rely on indium-based transparent conducting oxides (TCOs) to enhance the carrier extraction.This triggers interest towards TCO research from multiple perspectives: fundamental (making electrodes more conductive and broadband transparent), application-based (low-damage deposition methods) and economical (reduced Indium consumption).
Various strategies were followed to address the above mentioned challenges. Firstly, thinning down the industrial standard Sn-doped In2O3 (ITO) front electrode for SHJ cell applications was demonstrated. Additional anti-reflective capping allows it to exceed the efficiency values achieved with a standard ITO thickness. Alternatively, broadband transparency and conductivity of In-based oxide was enhanced with a more efficient Zr dopant. Zr-doped In2O3 (IZrO) displays higher electron mobility without compromising the optical properties as compared to ITO. Moreover, the optimized deposition conditions enabled integration of IZrO directly on top of the sensitive organic transport layer stack with minimum interfacial damage in emerging halide perovskite solar cells. Finally, properties of an emerging BaSnO3 TCO material were investigated, and the roadmap for photovoltaic devices with In-free transparent electrodes was drafted.
Noteworthy, all TCO thin films in the study were fabricated by the less established (as compared to the sputtering) pulsed laser deposition method. Encouraging TCO materials properties and successful damage-free device integration highlight the advantages of the deposition technique motivating further research activities in the photovoltaic community.