Thermal decomposition kinetics of FAPbI3 thin films

Thermal degradation in methylammonium–formamidinium–guanidinium lead iodide perovskites

“…This is exemplified by the number of different models that can be employed to interpret results. 47 However, the results presented here were obtained using the same methodology, so a self-comparison is quite reasonable. That said, the time and temperaturedependent XRD data used in this study are summarized in Supplementary Note 1 (ESI †), while details of the modeling used are given in Supplementary Note 2 (ESI †).…”

“…Extensive elaborations of the limitations of the use of areas in this type of study, and how to deal with them, can be found elsewhere. 47,57 Despite that, other similar studies were based in the area of the selected XRD peaks. [48][49][50] Potential quantitative errors are clear and so making direct comparisons between the various results present in the literature is difficult as the results are highly sensitive to experimental conditions, material architecture, and the methods used in data analysis.…”

“…38 For all purposes, computational methods, such as density functional theory (DFT) and molecular dynamics (MD) calculations, are valuable tools for predictions and mechanistic insights related to the degradation and stability of halide perovskites and related materials. [39][40][41][42][43] Although the thermal stability and thermal degradation kinetics have been studied in other perovskites and perovskite-like materials with different Asite cations, such as Cs + , formamidinium (or FA + ), and tetramethylammonium, [44][45][46][47] and some mixed-systems, 28,30,48,[49][50][51][52][53] studies on the systematized effects of A-site solid solutions containing different cations and concentrations on the thermal stability of halide perovskites are still scarce. It was recently noted that, chemically, the thermal degradation induction of a secondary phase segregation acts as an additional perovskite degradation route, which provokes a change from first to second-order degradation kinetics and an unexpectedly higher thermal degradation rate.…”

Vapor phase deposition of perovskite photovoltaics: short track to commercialization?

“…Generally, it is believed that the complex evaporation characteristics in these co-evaporation approaches accompanied by a complex set of chemical interactions between the inorganic and organic compounds as well as potential decomposition products of the chemically fragile organic halides (see Discussion below), 52,56–60 strain related effects, 61,62 and the limited thermal stability of perovskite materials that restricts the use of high-temperature, diffusion-assisted deposition processes are the main reasons for the non-ideal crystallization dynamics and in turn small grain sizes. 63–65 Furthermore, considering that significant morphological improvements in solution-processed approaches have been achieved by adding additives that slow down reaction rates ( e.g. , DMSO) or control crystal growth ( e.g.…”

“…Generally, it is believed that the complex evaporation characteristics in these co-evaporation approaches accompanied by a complex set of chemical interactions between the inorganic and organic compounds as well as potential decomposition products of the chemically fragile organic halides (see Discussion below), 52,[56][57][58][59][60] strain related effects, 61,62 and the limited thermal stability of perovskite materials that restricts the use of high-temperature, diffusionassisted deposition processes are the main reasons for the nonideal crystallization dynamics and in turn small grain sizes. [63][64][65] Furthermore, considering that significant morphological improvements in solution-processed approaches have been achieved by adding additives that slow down reaction rates (e.g., DMSO) or control crystal growth (e.g., alkylammonium chloride), it can be inferred that the lack of similar studies on these approaches for vapor-based processes is another reason for smaller grain sizes compared to the solution-based counterparts. 66,67 Recently, alternative deposition strategies, particularly sequential deposition methods, have been shown to result in improved absorber morphologies with notable improvements in open-circuit voltages as a result of the changing film formation mechanism.…”