microrods were prepared on mica substrates by chemical vapor deposition(CVD) method. The morphology and crystal structure of the samples were characterized by scanning electron microscopy(SEM) and X-ray diffraction(XRD). The CsPbBr
3
exciton luminescence was studied by temperature-dependent photoluminescence(PL) spectra from 10 K up to room temperature. The results reveal that there are two emission peaks at 10 K
which were attributed to exciton emission. The peak energy at 2.328 eV with a full width at half maximum(FWHM) of 20 meV was identified to free exciton recombination
and the peak energy at 2.313 eV with a FWHM of 29 meV was assigned to bound exciton emission. The peak energy of the free exciton monotonically blueshifts with the temperature increases
and so does the bound exciton until 120 K. Above 120 K
however
the peak energy of bound exciton tends to be flat when the temperature increases. Furthermore
the FWHM of the free exciton or bound exciton increases gradually. We have demonstrated these temperature-dependent photoluminescence properties are mainly due to the interaction between exciton and longitudinal optical phonons(LO). Our results could provide deeply understanding of intrinsic excitonic properties of CsPbBr
3
perovskites
which may be helpful to the development of high-performance optoelectronic devices.
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Keywords
references
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