Nanoscale metal organic frameworks offer unique advantages for the development of materials for solar energy conversion systems, supercapacitors, batteries and fuel cells.

The spatial heterogeneity of carrier dynamics in polycrystalline metal halide perovskite (MHP) thin films has a strong influence on photovoltaic device performance; however, the underlying cause has not yet been clearly understood. Here we report the sub-micrometer scale mapping of charge carrier dynamics in CH 3 NH 3 PbI 3 thin films using time-resolved nonlinear optical microscopy, specifically transient absorption microscopy (TAM) with sub-picosecond (ps) and time-resolved photoluminescence (PL) microscopy with nanosecond temporal resolution. To study the influence of physical morphology on charge carrier dynamics, MHP thin films having granular-and fibrous structures were investigated. On both types of films, spatial regions with short-lived transient gain signals (fast non-radiative relaxation within ~ 1 ps) typically show slower charge recombination via radiative relaxation, which we attribute to the presence of additional energy states near the band edge. In addition, fibrous films show longer PL lifetimes. Interestingly, the functional contrast shown Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff))

Halide exchange in palladium(ii) complexes with NNN-type pincer ligands is investigated.

The spatial heterogeneity of carrier dynamics in mixed halide perovskite CH3NH3PbI3−xClx thin films with a range of different chloride additions is mapped using femtosecond transient absorption microscopy (TAM). The comparison of TAM images of fibrous and granular polycrystalline CH3NH3PbI3−xClx films indicates that the impact of chloride addition on the local heterogeneity of carrier dynamics is highly dependent on the film preparation method and the resulting morphology. In addition to signals of pristine CH3NH3PbI3, CH3NH3PbI3−xClx films with a fibrous structure show long-lived excited state absorption (ESA) signals in localized, microscopic regions. The ESA signal exhibits transient absorption with a rise time of about 5 ps after the excitation pulse, indicating that these distinct micrograins have preferential carrier trapping properties. The chemical composition of these micrograins does not differ detectably from their surroundings. In contrast, in CH3NH3PbI3−xClx films with a granular structure, Cl addition does not seem to affect the charge carrier dynamics. These results provide insight into the localized effects of halide mixing and on the resulting photophysical properties of mixed halide perovskite materials on the micrometer length scale.