Composition‐Property Relations for GA_xFA_yMA_1‐x‐yPbI₃ Perovskites

Abstract

Halide perovskites are materials for diverse optoelectronic applications owing to a combination of factors, including their compositional flexibility. A major source of this diversity of compositions comes from the use of mixed organic cations in the A‐site of such compounds to form solid solutions. Many organic cations are possible for this purpose. Although significant progress is made over years of intensive research, the determination of systematic relationships between the compositions and properties of halide perovskites is not exploited accordingly. Using the MAPbI3 prototype, a wide range of compositions substituted by formamidinium (FA+) and guanidinium (GA+) cations are studied. From a detailed collection of experimental data and results reported in the literature, heat maps correlating the composition of GAxFAyMA1‐x‐yPbI3 solid solutions with phase transition temperatures, dielectric permittivity, and activation energies are constructed. Considering the characteristics of organic cations, namely their sizes, dipole moments, and the number of N─H bonds, it is possible to interpret the heat maps as consequences of these characteristics. This work brings a systematization of how obtaining specific properties of halide perovskites might be possible by customizing the characteristics of the A‐site organic cations.

Thermal degradation in methylammonium–formamidinium–guanidinium lead iodide perovskites

“…In this case, for compositions with high initial GA + concentrations, a smaller degradation extent would be required to reach local GA + supersaturation and trigger GAPbI 3 segregation. Also, it must be considered that the higher the concentration of GA + , the greater the mitigation of ion transport 64,65 therefore, the more difficult (slow) the redistribution of ions would be, translating into the local concentration of GA + increasing quicker. Given this plausible scenario, we studied the thermal degradation behavior of GA x MA 1Àx PbI 3 compositions with x up to 0.20.…”

High-entropy alloy screening for halide perovskites

“…, CsPbI 3 's metastable polymorphs). 1,2 There are more reports of single-phase inorganic HEAHP (Table S4, ESI†) 71–219 and hybrid organic–inorganic HEAHP (Table S5, ESI†), 220–285 but more investigation into single-phase boundaries is needed to confirm the broadscale applicability of UCV for screening HEAHP.…”

Key Roles of Interfaces in Inverted Metal-Halide Perovskite Solar Cells

“…42,73,74 In previous studies, it has been found that the advantages of packaged crystalline films that can be modulated by a variety of compositions come along with challenges. 16,75,76 In recent record-breaking studies, multicomponent hybrid perovskites have come to the fore. 77 For example, the introduction of A-site cations with different radius can improve the efficiency of the device but at the same time may also bring more surface defects.…”