The optoelectronic properties of lead halide perovskites strongly depend on their underlying crystal symmetries and dynamics, sometimes exhibiting a dual photoluminescence (PL) emission via Rashba-like effects. Here we exploit spin-and temperature-dependent PL to study single crystal APbBr3 (A= Cs and methylammonium; CH3NH3) to evaluate peak energy, intensity and linewidth evolutions of the dual emissions. Both materials are identified to have two temperature regimesabove and below approximately 100 Kbeing governed by different carrier scattering and radiative recombination dynamics. With increasing temperature, high-energy optical phonons (>11 meV) are found to drive energy splitting of the dual bands and electron-longitudinal-optical-phonon coupling dominates the linewidth broadening, with a stronger coupling constant inferred in CsPbBr3 for the spin-split indirect bands (78 meV) compared to the direct one (54 meV). We find the unusual thermal evolution of all-inorganic CsPbBr3 and hybrid MAPbBr3 perovskites are comparablesuggesting A-site independence and dominance of dynamic spin-splitting effectsand are best understood within a framework which accounts for bulk Rashba-like effects. The interest for solution-processable lead halide perovskites within efficient solar cells 1,2 stems from their promising optoelectronic response to the solar photons and high tolerance to defects 3,4. This family of semiconductors are increasingly being considered as "soft" solid-state materials 5-7 , whereby the fate of photo-generated charges primarily rely on the fundamental carrier-lattice interaction dynamics. For instance, polaron formationvia carrier-longitudinaloptical-phonon (Fröhlich) interactionswithin the lattice has been linked to several favourable qualities, like long carrier lifetimes and diffusion lengths 8-10. Recent indications of spin splitting and indirect tail state formation in lead halide perovskites 11-16 due to Rashba-like effects 17 motivate a reconsideration of how electron-phonon coupling can exist within its perturbed electronic band structure. Universally, for the application of any polar metal halide perovskite, the properties of the free charge carriers and phonon scattering mechanisms are central to its optoelectronic performance at room temperature (RT).

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UiO-66 is known as one of the most robust metal-organic framework materials. Nevertheless, UiO-66 has also been shown to undergo post-synthetic exchange of structural linkers with surprising ease in some solvents. To date, the exchange mechanism has not yet been fully elucidated. Here, we show how timeresolved monitoring grants insight into the selected case of exchanging 2-aminoterephthalate into UiO-66 in methanol. Analysis of both the solid and liquid phase, complemented by computational insights, revealed the active role of methanol in the creation and stabilization of dangling linkers. Similar to monocarboxylate defects that can be introduced during UiO-66 synthesis, such dangling linkers undergo fast exchange. The presence of missing linker or missing cluster defects at the start of the exchange process was shown to have no considerable impact on the equilibrium composition. After the exchange process, the incoming 2aminoterephthalate and remaining terephthalate linkers were distributed homogeneously in the framework for the typical sub-micron size of UiO-66 crystallites.