We present a temperature-dependent photoluminescence (PL) study of solution-grown CsPbBr3 bulk crystal and thin film, using one-photon and two-photon excitations. Twin planes are observed in X-ray diffraction spectra in crystal. In analyzing PL peak position and spectral widths as function of temperature, we find that the electron–phonon interaction is generally stronger in CsPbBr3 crystals than in films. Moreover, with one photon excitation, emissions from excitons and trapped excitons are observed in CsPbBr3 crystal. Under two-photon excitation, only the emissions from trapped excitons are observed in bulk crystal. Our work demonstrates that two-photon excitation PL is more sensitive to the trapped excitons inside CsPbBr3, implicating an optical method to probe the inside quality of the crystal.
Li et al. (Wed,) studied this question.