Aboma Merdasa
Researcher
Alkali Salts as Interface Modifiers in n-i-p Hybrid Perovskite Solar Cells
Author
Summary, in English
After demonstration of a 23% power conversion efficiency, a high operational stability is the next most important scientific and technological challenge in perovskite solar cells (PSCs). A potential failure mechanism is tied to a bias-induced ion migration, which causes current–voltage hysteresis and a decay in the device performance over time. Herein, alkali salts are shown to mitigate hysteresis and stabilize device performance in n-i-p hybrid planar PSCs. Different alkali salts of potassium chloride, iodide, and nitrate as well as sodium chloride and iodide are deposited from aqueous solution onto the n-type contact, based on SnO2, prior to deposition of the perovskite absorber Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3. Introduction of potassium-based alkali salts suppresses the current–voltage hysteresis and stabilizes the operational device stability at the maximum power point. This is attributed to the suppression of hole trapping at the n-type selective transport layer (SnO2)/perovskite interface observed by surface photovoltage spectroscopy, which is interpreted to reduce interfacial recombination and improve charge carrier extraction. The best and most stable performance of 19% is achieved using potassium nitrate as the interface modifier. Devices with higher and more stable performance exhibit substantially lower current transients, analyzed during maximum power point tracking.
Department/s
- Chemical Physics
- NanoLund: Centre for Nanoscience
Publishing year
2019-09
Language
English
Publication/Series
Solar RRL
Volume
3
Issue
9
Document type
Journal article
Publisher
Wiley-Blackwell
Topic
- Materials Chemistry
Keywords
- alkali salts
- interface modification
- n-i-p devices
- perovskite solar cells
Status
Published
ISBN/ISSN/Other
- ISSN: 2367-198X