The β-Cs₃Cu₂Cl₅ nanocrystals were developed as high-performance scintillators, which showed a PLQY of 94.6% and a radioluminescence light yield of ∼34000 photons per MeV. A high spatial resolution in the X-ray imaging results was demonstrated.

The morphology and crystalline quality of perovskite layers are crucial to fabricate high efficiency and high stability perovskite solar cells (PSCs). In this work, we investigated how the substrate temperature influences the crystallization process of the mixed-ion perovskite material (FAPbI3)_0.85(MAPbBr₃)_0.15. The intermediate phase formation, the following perovskite phase transformation, and the film morphology were studied by spin-coating the perovskite material onto hot substrates using microscopy and X-ray diffraction methods. The results show that elevating the substrate temperature alters the morphology of perovskite films from pure dendritic to dendritic/island co-existing structures. The appearance of islands increases the defect density in the perovskite layer and deteriorates the device performance. The substrate temperature has to be controlled in a certain range to form a high crystallinity perovskite layer. The morphology evolution mechanism was also discussed. This work provided a better understanding of the roles of DMSO and temperature in the crystallization process, which will provide more opportunities and guidance for the upscaling of mixed-ion perovskite solar cell manufacturing.

Understanding the nature of photogenerated carriers and their subsequent dynamics in semiconducting perovskites is important for the development of solar cell materials and devices. However, most ultrafast dynamic measurements on perovskite materials were conducted under high carrier densities, which likely obscures the genuine dynamics under low carrier densities in solar illumination conditions. In this study, we presented a detailed experimental study of the carrier density-dependent dynamics in hybrid lead iodide perovskites from femtosecond to microsecond using a highly sensitive transient absorption (TA) spectrometer. From the dynamic curves with low carrier density in the linear response range, we observed two fast trapping processes that occurred in less than 1 ps and tens of picoseconds, attributed to the shallow traps, and two slow decays with lifetimes of hundreds of nanoseconds and longer than 1 μs, related to the trap-assisted recombination and trapping at deep traps. Further TA measurements clearly show that PbCl₂ passivation can effectively reduce both shallow and deep trap densities. These results provide insights into the intrinsic photophysics of semiconducting perovskites with direct implications for photovoltaic and optoelectronic applications under sunlight.