Abstract
The interaction between electrons and phonons in CsPbBr3 is essential for the design of CsPbBr3 based optoelectronics since the phonon governs emission line broadening in metal halide perovskites. In this work, the temperature dependent photoluminescence linewidth was obtained from 80 K to 400 K. Density functional theory and many-body perturbation theory were used to calculate the electron–phonon coupling in CsPbBr3. We demonstrate that the electron–phonon coupling is dominated by the longitudinal optical phonon. In addition, the photoluminescence spectrum broadening is almost linear with temperatures from 80 K to 400 K. Their results provide a better understanding of the mechanism of electron–phonon scattering in CsPbBr3 and related optoelectronic devices.
Highlights
In the past few years, lead halide perovskites have attracted much attention in the field of solar cells based on perovskite thin films due to their high power conversion efficiency, such as MAPbI3 and MAPbBr3 (MA: CH3NH3).1–3 Recently, it has been found that lead halide perovskites exhibit excellent luminescence properties, which are suitable for light emitting diodes (LEDs)
Compared with the PL spectra of MAPbBr3, which exhibit an abrupt shift in PL peak energy at about 150 K,18 the PL spectrum peak energy of CsPbBr3 exhibits a steady increase as the temperature increases
CsPbBr3 undergoes phase transition from the orthorhombic to tetragonal phase at about 361 K and phase transition from the tetragonal to cubic phase at about 403 K,38 we could not observe any abrupt shift of the PL peak in Fig. 2(a) because there is no reduction in the rotational freedom of the Cs+ cation during the phase transition
Summary
In the past few years, lead halide perovskites have attracted much attention in the field of solar cells based on perovskite thin films due to their high power conversion efficiency, such as MAPbI3 and MAPbBr3 (MA: CH3NH3). Recently, it has been found that lead halide perovskites exhibit excellent luminescence properties, which are suitable for light emitting diodes (LEDs). In order to address this issue, several groups have examined the temperature dependence mobility, which is only governed by deformation potential scattering with acoustic phonons.15 They found that the mobility is almost proportional to T1.5, which is close to the theoretical result of electron–phonon coupling at room temperature. The experimental photoluminescence (PL) linewidth of CsPbBr3 as a function of temperature has been obtained between 80 K and 400 K in order to investigate the charge-carrier scattering mechanism in inorganic lead halide perovskites. We further demonstrate that the experimental results are in good agreement with the theoretical results Both results indicate that the Fröhlich coupling to the LO phonon is the main reason for the linewidth broadening in inorganic lead halide perovskites
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