ALD of Al2O3 on Perovskite Solar Cells: Role of Active Interfacial Engineering
Shaibal K. Sarkar a
a IIT Indian Institute of Technology Bombay, Department of Energy Science and Engineering, Powai, Mumbai, Maharashtra, India, Mumbai, India
Proceedings of Online Conference on Perovskites for Energy Harvesting: From Fundamentals to Devices (PERENHAR)
Online, Spain, 2020 November 19th - 20th
Organizers: Dinesh Kabra, Sandheep Ravishankar, Angshuman Nag and Priya Mahadevan
Invited Speaker, Shaibal K. Sarkar, presentation 039
Publication date: 2nd November 2020

Atomic Layer Deposition of ultrathin Al2O3 on hybrid perovskite solar cells drew significant attention due to the considerable improvement in the overall device stability. In our laboratory, with intermittent current-voltage measurements, the coated devices show the value of T80>7500 hours under ambient conditions. Subsequently, these coated devices are found highly stable when measured in a cyclic manner for 7 days, replicating the real-life day-night sequences. Such encapsulation is found very effective as an oxygen barrier-layer and water-impermeable membrane; hence contribute to the overall stability of these devices.

In this presentation, I would like to emphasize on our experimental findings, subsequently supported by device simulation, which undoubtedly reveals that the perovskite-spiroOMeTAD interfacial band-structure play a detrimental role in initiating the degradation processes in the pristine devices (device structure). We try to provide a comprehensive insight depicting an apparently non-trivial active phenomenon resulted due to the ALD grown Al2O3 layer that supposedly be a passive component of the entire device stack. Favored electronic modification of the spiro-OMeTAD/perovskite interface resulted due to the Al2O3 ALD provides better charge extraction and lesser ionic accumulation, unlike the unencapsulated devices, and hence offers better performance stability. Our study indicates that essentially the ionic accumulation triggers the device degradation that is eventually followed by materials degradation.

I acknowledge the Ministry of New and Renewable Energy, Government of India for financial support.

© Fundació Scito
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