Formation of hybrid ABX₃perovskite compounds for solar cell application: first-principles calculations of effective ionic radii and determination of tolerance factors

Abstract

The development of hybrid organic-inorganic perovskite solar cells is one of the most rapidly growing fields in the photovoltaic community and is on its way to challenge polycrystalline silicon and thin film technologies. High power conversion efficiencies can be achieved by simple processing with low cost. However, due to the limited long-term stability and environmental toxicity of lead in the prototypic CHNHPbI, there is a need to find alternative ABX constitutional combinations in order to promote commercialization. The Goldschmidt tolerance factor and the octahedral factor were found to be necessary geometrical concepts to evaluate which perovskite compounds can be formed. It was figured out that the main challenge lies in estimating an effective ionic radius for the molecular cation. We calculated tolerance factors and octahedral factors for 486 ABX monoammonium-metal-halide combinations, where the steric size of the molecular cation in the A-position was estimated concerning the total charge density. A thorough inquiry about existing mixed organic-inorganic perovskites was undertaken. Our results are in excellent agreement with the reported hybrid compounds and indicate the potential existence of 106 ABX combinations hitherto not discussed in the literature, giving hints for more intense research on prospective individual candidates.

Partial cation substitution reduces iodide ion transport in lead iodide perovskite solar cells

“…Although most of the cations are either too large or small to form a 3D perovskite phase on their own, they can be partially substituted into MAPbI 3 to create binary mixed-cation systems. 19,25,26 As phase separation can occur above certain substitution ratios, A-site doping was limited experimentally to 5% corresponding to MA 0.95 A 0.05 PbI 3 . Although it has been reported that Rb does not act as an A-site cation in FA-based perovskites, it can be incorporated alongside other smaller additives.…”

A hybrid organic-inorganic perovskite dataset

“…In fact, this idea has recently been emerging with some datasets of hybrid organic/inorganic perovskites, prepared at some level of computations 27,28 . Our dataset, which contains 1,346 HOIPs, is prepared uniformly at the level of density functional theory (DFT) 29,30 from the initial structures predicted by the minima-hoping method 31,32 .…”

An Aromatic Diamine Molecule as the A‐Site Solute for Highly Durable and Efficient Perovskite Solar Cells

“…Imidazole (IZ) has a reasonable ionic radius of 258 pm with an aromatic structure, allowing good solid solution with MAPbI 3 . Moreover, the diammonium molecule can provide additional hydrogen bonding for a stable material, and due to the delocalized π orbital of IZ with hydrogen bonding in a I–Pb cage, it may allow low reactivity with its surroundings leading to additional electrical conductivity. Thereby, the devices with IZ‐alloyed MAPbI 3 have achieved reverse PCEs up to 20.2% with outstanding stability from light‐, air‐, and heat‐induced environments.…”