TiO2-Assisted Halide Ion Segregation in Mixed Halide Perovskite Films
Jeffrey DuBose a b, Prashant Kamat a b
a Department of Chemistry, University of Notre Dame, United States
b Radiation Laboratory, University of Notre Dame, US, United States
Poster, Jeffrey DuBose, 035
Publication date: 23rd April 2020
ePoster: 

In metal halide perovskite solar cells, electron transport layers (ETLs) such as TiO2 dictate the overall photovoltaic performance. However, the same electron capture property of ETL indirectly impacts halide ion mobility as evident from the TiO2-assisted halide ion segregation in mixed halide perovskite (MHP) films under pulsed laser excitation (387 nm, 500 Hz). This segregation is only observed when deposited on an ETL such as TiO2 but not on insulating ZrO2 substrate. Injection of electrons from excited MHP into the ETL (ket = 1011 s–1) followed by scavenging of electrons by O2 causes hole accumulation in the MHP film. Localization of holes on the iodide site in the MHP induces instability causing iodide from the lattice to move away toward grain boundaries. Suppression of segregation occurs when holes are extracted by a hole transport layer (spiro-OMeTAD) deposited on the MHP, thus avoiding hole build-up. These results provide further insight into the role of holes in the phase segregation of MHPs and hole mobility in perovskite solar cells.

© Fundació Scito
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info