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Stability of Perovskite Solar Cells


Speaker:Prof. A.B. Djurišić
Affiliation:Department of Physics, HKU
Date:August 3, 2017 (Thursday)
Time:4:00 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract
 

Organometallic halide perovskites are the fastest growing new solar cell technology, with dramatic improvements in the efficiency from ~10% in the first solid state devices in 2012 to over 22% in 2016. The optimization of the perovskite film deposition and composition, as well as device architecture, has resulted in significant improvements in the efficiency and it has been the primary focus of perovskite solar cell research. However, despite their great promise for inexpensive and efficient solar cells, one significant drawback of organometallic halide perovskite materials is that can rapidly degrade upon exposure to moisture, in particular under illumination and at elevated temperature. Consequently, stability of these devices is a significant concern and the largest obstacle towards their practical applications. 
 

While the stability testing has been reported for these devices, the majority of the reports involve stability testing using storage without illumination, which overestimates the lifetime. The reports on the stability involving light soaking have been relatively scarce, and the data for outdoor testing have been even more scarce with very few research groups reporting outdoor stability. In this talk, degradation mechanisms of organometallic halide perovskite films and devices will be discussed, followed by discussion of device stability under light soaking at elevated temperature, as well as outdoor testing in a hot and humid weather (Hong Kong summer weather). Standard ISOSL2 and ISOS-O1 protocols are used for testing. Different encapsulation strategies, as well as desiccants and protective layers will be discussed. Finally, we demonstrate that with an optimized encapsulation strategy, stable performance for hundreds of hours can be achieved, with testing period including amber rainstorm and typhoon warnings. This indicates that the organometallic halide perovskite solar cells can overcome the stability challenges and that they are indeed among the most promising emerging photovoltaic technologies.                                                              

Coffee and tea will be served 20 minutes prior to the seminar.

Anyone interested is welcome to attend.