| Autor: |
Ceratti, D R, Cohen, A V, Tenne, R, Rakita, Y, Snarski, L, Cremonesi, L, Goldian, I, Kaplan-Ashiri, I, Bendikov, T, Kalchenko, V, Elbaum, M, Potenza, M A C, Kronik, L, Hodes, G, Cahen, D |
| Rok vydání: |
2020 |
| Předmět: |
|
| Druh dokumentu: |
Working Paper |
| Popis: |
We find significant differences between degradation and healing at the surface or in the bulk for each of the different APbBr3 single crystals (A=CH3NH3+, methylammonium (MA); HC(NH2)2+, formamidinium (FA); and cesium, Cs+). Using 1- and 2-photon microscopy and photobleaching we conclude that kinetics dominate the surface, and thermodynamics the bulk stability. Fluorescence-lifetime imaging microscopy, as well as results from several other methods, relate the (damaged) state of the halide perovskite (HaP) after photobleaching to its modified optical and electronic properties. The A cation type strongly influences both the kinetics and the thermodynamics of recovery and degradation: FA heals best the bulk material with faster self-healing; Cs+ protects the surface best, being the least volatile of the A cations and possibly through O-passivation; MA passivates defects via methylamine from photo-dissociation, which binds to Pb2+. DFT simulations not only provide insight into the latter conclusion, but also show the importance and stability of the Br3- defect. These results rationalize the use of mixed A-cation materials for optimizing both solar cell stability and overall performance of HaP-based devices, and provide a basis for designing new HaP variants. |
| Databáze: |
arXiv |
| Externí odkaz: |
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