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Photophysics of Organic-Inorganic Hybrid Lead Iodide Perovskite Single Crystals.
- Source :
-
Advanced Functional Materials . Apr2015, Vol. 25 Issue 16, p2378-2385. 8p. - Publication Year :
- 2015
-
Abstract
- Hybrid organometal halide perovskites have been demonstrated to have outstanding performance as semiconductors for solar energy conversion. Further improvement of the efficiency and stability of these devices requires a deeper understanding of their intrinsic photophysical properties. Here, the structural and optical properties of high-quality single crystals of CH3NH3PbI3 from room temperature to 5 K are investigated. X-ray diffraction reveals an extremely sharp transition at 163 K from a twinned tetragonal I4/mcm phase to a low-temperature phase characterized by complex twinning and possible frozen disorder. Above the transition temperature, the photoluminescence is in agreement with a band-edge transition, explaining the outstanding performances of the solar cells. Whereas below the transition temperature, three different excitonic features arise, one of which is attributed to a free-exciton and the other two to bound excitons (BEs). The BEs are characterized by a decay dynamics of about 5 μs and by a saturation phenomenon at high power excitation. The long lifetime and the saturation effect make us attribute these low temperature features to bound triplet excitons. This results in a description of the room temperature recombination as being due to spontaneous band-to-band radiative transitions, whereas a diffusion-limited behavior is expected for the low-temperature range. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1616301X
- Volume :
- 25
- Issue :
- 16
- Database :
- Academic Search Index
- Journal :
- Advanced Functional Materials
- Publication Type :
- Academic Journal
- Accession number :
- 102187491
- Full Text :
- https://doi.org/10.1002/adfm.201404421