- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Optical properties of CH3NH3PbI3 crystal grown using inverse temperature crystallization
摘要： Perovskite CH3NH3PbI3 (MAPbI3) single crystal was grown using inverse temperature crystallization method. Crystallinity of the perovskite was con?rmed by X-ray di?raction. Photoluminescence (PL) spectra revealed abnormal behavior due to a temperature-induced orthorhombic to the tetragonal phase transition. Four PL emission peaks, A, B, C, and D, were observed in the low temperature regime. Peaks A and B were observed at 756 and 776 nm at 12 K, and were blue-shifted and disappeared at 130 and 70 K, respectively. Peaks C and D were observed at 789 and 807 nm at 40 K and were also blue-shifted to 780 and 794 nm at 100 K. On the other hand, the peak C red-shifted to 799 nm from 100 to 140 K because of an orthorhombic to the tetragonal phase change and was also blue-shifted above 140 K. From the excitation intensity- and temperature-dependent PL results, peaks A and B were assigned to the free-exciton and bound-exciton of the orthorhombic phase crystal, respectively. In addition, peaks C and D were associated with the free-exciton and bound-exciton of the tetragonal phase crystal, respectively. The activation energy of peak C was calculated to be 98 meV from temperature dependence of the PL intensity.
关键词： Phase transition,MAPbI3,Perovskite,Photoluminescence,Exciton
更新于2025-09-10 09:29:36
-
The Effect of Crystal Grain Orientation on the Rate of Ionic Transport in Perovskite Polycrystalline Thin Films
摘要： In this work, we examine the effect of microstructure on ion migration induced photoluminescence (PL) quenching in methylammonium lead iodide perovskite films. Thin films were fabricated by two methods: spin-coating, which results in randomly oriented perovskite grains, and zone-casting, which results in aligned grains. As an external bias is applied to these films, migration of ions causes a quenching of the PL signal in the vicinity of the anode. The evolution of this PL-quenched zone is less uniform in the spin-coated devices than in the zone-cast ones, suggesting that the relative orientation of the crystal grains plays a significant role in the migration of ions within polycrystalline perovskite. We simulate this effect via a simple Ising model of ionic motion across grains in the perovskite thin film. The results of this simulation align closely with the observed experimental results, further solidifying the correlation between crystal grain orientation and the rate of ionic transport.
关键词： zone-casting,ion migration,microstructure,photoluminescence,MAPbI3 perovskite
更新于2025-09-10 09:29:36