Enhanced UV stability of perovskite solar cells with a SrO interlayer

• Published in: Organic electronics Vol. 63; pp. 343 - 348
• Main Authors: Lee, Sang-Won, Kim, Seongtak, Bae, Soohyun, Cho, Kyungjin, Chung, Taewon, Hwang, Jae-Keun, Song, Inseol, Lee, Wonkyu, Park, Sungeun, Jung, Jaebong, Chun, Jihun, Lee, Yoon Jung, Moon, Yeon Ji, Lee, Hae-Seok, Kim, Donghwan, Mo, Chan Bin, Kang, Yoonmook
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2018
• Subjects: Interface passivation; Micro-photoluminescence; Perovskite solar cell; Strontium oxide; UV stability; CCD; Interface passivation; Micro-photoluminescence; TFSI; Perovskite solar cell; PCE; MAI; EDS; EQE; SEM; XPS; IPA; UV stability; ETL; Strontium oxide; μ-PL; DSSC
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2018.09.019

We investigated strontium oxide (SrO) as an interlayer material to enhance the UV stability of a CH3NH3PbI3 perovskite solar cell. Moisture and over 400 nm wavelength of light were excluded to investigate the effect of UV light only. Two different interlayer fabrication processes were examined to optimize the performance of this solar cell. Devices fabricated by dipping for 30 min in SrO solution exhibited photoconversion efficiencies of 15.5%, whereas those fabricated with 60-min dipping showed photoconversion efficiencies of 15% and exhibited local Sr agglomeration. Devices with SrO displayed lower initial efficiencies than those without any SrO layer (17.6%), However, a device without SrO retained only 34.4% of its initial efficiency after 100 h of UV exposure. In contrast, SrO-incorporated devices retained almost 60.0% of their initial efficiency. Severe μ-PL mapping intensity degradation was observed in devices that did not include the interlayer, but no degradation was observed in those with the SrO interlayer. This can be attributed to the passivation of the degradation sites by SrO.
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•Perovskite UV stability was tested under conditions except moisture, oxygen and wavelengths exceeding 400 nm.•With high resolution μ-PL mapping technique, direct evidence is provided about the area perovskite UV degradation begins.•UV degradation is initiated at the ETL/perovskite interface.•Effect of the SrO interlayer on UV stability was examined in an inert atmosphere.•UV stability is enhanced by SrO interface passivation.