Wang, Liangling ; Zheng, Wei ; Vitale, Francesco ; Zhang, Xiangzhou ; Li, Xiuling ; Ji, Yanchen ; Liu, Zhen ; Ghaebi, Omid ; Plass, Christian T. ; Domes, Robert ; Frosch, Torsten ; Soavi, Giancarlo ; Wendler, Elke ; Zhang, Yuhai ; Ronning, Carsten (2022)
Wide‐Bandgap Double Perovskites with Multiple Longitudinal‐Optical Phonon Scattering.
In: Advanced Functional Materials, 32 (22)
doi: 10.1002/adfm.202111338
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Alloyed lead-free double perovskites display intense photoluminescence, are environmentally friendly, and their devices show long-term operation. Thanks to these properties, which make them excellent warm white-emitting materials, they have recently received great attention in lighting applications. An important factor to tune the optical properties of alloyed lead-free double perovskites is the presence of self-trapped excitons. Here, it is demonstrated that in lead-free double perovskites, the strong electron–phonon coupling plays a crucial role in the generation of self-trapped excitons. The strong electron–phonon coupling is confirmed by a large Huang–Rhys factor and by the presence of multiphonon transitions. In particular, sharp emission lines superimposed on the broad photoluminescence emission band of one of these samples (Cs2Ag0.6Na0.4InCl6 0.5%Bi) are observed; these are due to the strong coupling of longitudinal-optical phonons with excited electronic states caused by the tetragonally distorted AgCl6 octahedrons. Such a strong coupling of longitudinal-optical phonons to electrons can effectively modulate the photophysical properties of alloyed double perovskites, and its understanding is, thus, of paramount importance for the design of future optoelectronic devices.

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