AuthorsSarmah, Smritakshi P.
Burlakov, Victor M.
El-Zohry, Ahmed M.
Alias, Mohd Sharizal
Zhumekenov, Ayan A.
Saidaminov, Makhsud I.
Cho, Nam Chul
Ajia, Idris A.
Roqan, Iman S.
Ooi, Boon S.
Mohammed, Omar F.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Imaging and Characterization Core Lab
Materials Science and Engineering Program
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AbstractUnderstanding defect chemistry, particularly ion migration, and its significant effect on the surface’s optical and electronic properties is one of the major challenges impeding the development of hybrid perovskite-based devices. Here, using both experimental and theoretical approaches, we demonstrated that the surface layers of the perovskite crystals may acquire a high concentration of positively charged vacancies with the complementary negatively charged halide ions pushed to the surface. This charge separation near the surface generates an electric field that can induce an increase of optical band gap in the surface layers relative to the bulk. We found that the charge separation, electric field, and the amplitude of shift in the bandgap strongly depend on the halides and organic moieties of perovskite crystals. Our findings reveal the peculiarity of surface effects that are currently limiting the applications of perovskite crystals and more importantly explain their origins, thus enabling viable surface passivation strategies to remediate them.
CitationSarmah SP, Burlakov VM, Yengel E, Murali B, Alarousu E, et al. (2017) Double Charged Surface Layers in Lead Halide Perovskite Crystals. Nano Letters 17: 2021–2027. Available: http://dx.doi.org/10.1021/acs.nanolett.7b00031.
SponsorsKing Abdullah University of Science and Technology (KAUST) supported the work reported here. The authors gratefully acknowledge funding support from KACST, Technology Innovation Center for Solid-State Lighting at KAUST.
PublisherAmerican Chemical Society (ACS)