Mesoporous interface mitigates the impact of defects in perovskite solar cells

January 19, 2018, Helmholtz Association of German Research Centres
SEM-images of the different perovskite solar cell architectures, left with planar interface, right with mesoporous interface. Images are coloured: metal oxide (light blue), interface (red), perovskite (brown), hole conducting layer (dark blue), topped with contact (gold).  Scale bar is 200 nm. Credit: A. Gagliardi/TUM

The nominal cell operating life of perovskite solar cells is strongly influenced by their inner architecture. This was shown by two scientists at the Helmholtz-Zentrum Berlin and the Technical University of Munich. They combined experiments with numerical simulations in order to explain this observation.

In only a few years, efficiencies of have been raised from 3 percent to more than 20 percent. Furthermore, the material is inexpensive and easy to process, suggesting a great future for photovoltaics. Unfortunately, there are still issues, including their nominal operating life: Conversion efficiencies decrease sharply when the material is exposed to UV radiation and electric fields, as is the case in real operating conditions. Now, Dr. Antonio Abate and Prof. Allessio Gagliardi, TU Munich, have published new results on the influence of the architecture of cells on their nominal operating life in the journal ACS Energy Letters.

The scientists explored different architectures of perovskite cells, preparing them under identical conditions using metal-oxide electron transport layers (ETL) such as TiO2 and SnO2. One group of had a planar interface between perovskite and ETL, whereas in the other one, a mesoporous interface intermingled perovskite and metal oxide to form a sponge-like structure containing a huge number of extremely tiny pores. Surprisingly, the perovskite cell with the mesoporous interface exhibited better output stability over time than the planar ETL-perovskite interface.

After careful experimental observations and , the scientists provided an explanation: "The benefit induced by the mesoporous is fundamentally due to its large surface area," Abate explains. Defects that compromise the power output and operating life and which accumulate during operation at the ETL tend to get diluted in this large surface.

The scientists even obtained a threshold density for those defects: Above a certain threshold, the output power of the solar cell decreases rapidly. But below this threshold, the maximum power output remains stable. "We demonstrated that devices in a mesoporous configuration are more resilient to defect accumulation than in a planar configuration," Abate concludes.

Explore further: Ultra-stable perovskite solar cell remains stable for more than a year

More information: Alessio Gagliardi et al, Mesoporous Electron-Selective Contacts Enhance the Tolerance to Interfacial Ion Accumulation in Perovskite Solar Cells, ACS Energy Letters (2017). DOI: 10.1021/acsenergylett.7b01101

Related Stories

Standardizing perovskite aging measurements

January 2, 2018

Perovskite solar cells are an alternative to conventional silicon solar cells, and are poised to overtake the market with their high power-conversion efficiencies (over 22% now) and lower capital expenditure and manufacturing ...

New way to make low-cost solar cell technology

November 14, 2016

Researchers at ANU have found a new way to fabricate high efficiency semi-transparent perovskite solar cells in a breakthrough that could lead to more efficient and cheaper solar electricity.

Researchers create single-crystal perovskite solar cells

August 29, 2017

Photovoltaic conversion is regarded as the ultimate solution to the growing demand for energy, yet traditional silicon-based solar cells are expensive to produce, and production itself involves intensive energy consumption. ...

Recommended for you

Technology near for real-time TV political fact checks

January 18, 2019

A Duke University team expects to have a product available for election year that will allow television networks to offer real-time fact checks onscreen when a politician makes a questionable claim during a speech or debate.

Privacy becomes a selling point at tech show

January 7, 2019

Apple is not among the exhibitors at the 2019 Consumer Electronics Show, but that didn't prevent the iPhone maker from sending a message to attendees on a large billboard.

China's Huawei unveils chip for global big data market

January 7, 2019

Huawei Technologies Ltd. showed off a new processor chip for data centers and cloud computing Monday, expanding into new and growing markets despite Western warnings the company might be a security risk.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.