Exciton-phonon scattering effects on photoluminescence of hybrid lead halide perovskite

Organometal halide perovskite materials have gained tremendous attention in the field of photovoltaic, light emitting and lasing devices. Perovskite materials offer some promising optical properties like tunable direct band gap, large light absorption coefficient, high quantum efficiency and long-range balanced electron-hole transport length. The mobility and the photoluminescence line width broadening in hybrid lead halide perovskite are affected by phonon scattering. For the development of efficient perovskite devices it is thus crucially important to establish how excitons interact with phonons in this material. Here we investigate the temperature dependence of the photoluminescence full width at half maximum (FWHM) for CH
₃
NH
₃
PM
₃
perovskite in the temperature regime of 10-300 K. We developed a quantitative model to calculate the photoluminescence (PL) peak energy variation as well as FWHM broadening adoptiong the Monte-Carlo simulation. Miller-Abrahams expression is used to incorporate the exciton hopping between the localized states assuming the Gaussian distribution of the excitons. Our computation elucidates that the FWHM broadens with increasing temperature due to scattering with exciton-optical phonons.