PhD-Postdoc series – Speaker change October 13th
Due to some unfortunate events, Lorena Perdigón Toro will not be able to present her research tomorrow (Wednesday, October 13th). Hence, her talk has to be rescheduled to November 24th.
To ensure the continuity of the series Jarla Thiesbrummel was kind enough to present earlier than planned. Jarla is a PhD Student from Henry Snaith’s group at the University of Oxford and she will tell us more on “Universal Current Losses in Perovskite Solar Cells Due to Mobile Ions”.
The talk will be held tomorrow (13-10-2021) at 5 PM (GMT+2)
Registration is still open at https://fau.zoom.us/j/64280322348?pwd=MFpvb25aYWtyYy9hS0tUOUR6Nk00QT09
Abstract:
We investigated the origin of current losses in perovskite solar cells, using a combination of voltage dependent photoluminescence (PL) timeseries and various charge extraction measurements. It was demonstrated that Pb/Sn-perovskite devices suffer from a reduction in the charge extraction efficiency within the first few seconds of operation, which leads to a loss in current and lower maximum power output. In addition, the emitted PL from the device rises on the exact same timescales due to the accumulation of electronic charges in the active layer. Using transient charge extraction measurements, we showed that these observations cannot be explained by doping-induced electronic charges but by the movement of mobile ions toward the perovskite/transport layer interfaces, which inhibits charge extraction due to band flattening. Finally, we generalized these findings to lead-based perovskites, showing that the loss mechanism is universal.
I will discuss the negative role mobile ions play in perovskite solar cells and how our findings pave the path towards understanding and mitigating a key loss mechanism. Furthermore, I will also give an outlook on what our results mean for perovskite-based tandem solar cells and I will present our recent progress on the development of these devices.