Influence of Metal-Ion Replacement on the Phase Stabilization of Cubic All-Inorganic Cesium Lead Halide Perovskites: an Ab Initio Thermodynamic Formalism for Solution-Processed Cation Doping

Abstract

All-inorganic metal-halide perovskites are demonstrating good prospects toward long-term stability and high efficiency in the field of perovskite photovoltaics. Stemming from CsPbI3, compositional engineering via cation and anion doping has been widely adopted to improve device performance, especially the perovskite phase stability. In contrast to anion doping with smaller halogens, experimentally observed cation-doping effects on the perovskite stability cannot be simply explained or predicted by the geometrical tolerance factor. Herein, we quantitatively estimate the cation-doping influence on the cubic phase stability, representatively, of CsPbI3 using an ab initio thermodynamic formalism adapted for considering solution-processed synthetic conditions such as the temperature and doping concentration. Experimentally endeavored or theoretically plausible 25 metal elements are chosen to be considered for replacing Cs and/or Pb in CsPbI3. Our calculations show that a traditional qualitative assessment of the metal doping influence in connection with the geometrical tolerance factor is not sufficient to provide a fundamental understanding of the real mechanism, emphasizing the cautiousness about the electropositivity of doping cations as well as their substitution probability.

First-principles study on structural, electronic and optical properties of halide double perovskite Cs2AgBX6 (B = In, Sb; X = F, Cl, Br, I)

“…elements. 14 Furthermore, halide double perovskites (HDPs) with 2ABX 3 → A 2 B 2 X 6 stoichiometry extend accessible B-site metals, allowing for the mixed-metal HDPs A 2 BB′X 6 (B = Au + , Ag + , Tl + , Na + , K + ; B′ = Au 3+ , Tl 3+ , Bi 3+ , In 3+ , Sb 3+ ) 15–17 and vacancy-ordered double perovskites A 2 B□X 6 (B = Sn 4+ , Te 4+ , Pd 4+ , etc. ).…”

“…elements. 14 Furthermore, halide double perovskites (HDPs) with 2ABX 3 / A 2 B 2 X 6 stoichiometry extend accessible B-site metals, allowing for the mixed-metal HDPs A 2 BB ′ X 6 (B = Au + , Ag + , Tl + , Na + , K + ; B ′ = Au 3+ , Tl 3+ , Bi 3+ , In 3+ , Sb 3+ ) [15][16][17] and vacancy-ordered double perovskites A 2 B,X 6 (B = Sn 4+ , Te 4+ , Pd 4+ , etc.). 18,19 The homovalent substituting Sn 2+ or Ge 2+ for toxic Pb 2+ in ABX 3 single perovskites gives rise to instability against oxidation, 20,21 whereas the heterovalent replacement by mono-and tri-valent cations in A 2 BB ′ X 6 (ref.…”

In situ crystal reconstruction strategy-based highly efficient air-processed inorganic CsPbI2Br perovskite photovoltaics for indoor, outdoor, and switching applications

“…Organic-inorganic metal halide perovskites are considered the most promising materials for next-generation photovoltaic technology owing to their outstanding optoelectronic properties, such as a long charge carrier diffusion length, high carrier mobility, a tunable optical bandgap, low trap density, higher optical absorption, low exciton binding energy, [1][2][3][4] lowtemperature solution processibility, and cost-effective fabrication approaches. The highest certified power conversion efficiency (PCE) of perovskite solar cells (PSCs) has rapidly increased from 3.8% to 25.5% 5,6 in the past few years, which is close to the state-of-the-art Si-based solar cell performance.…”

Ternary System CsI–PbI2–BiI3 and Thermodynamic Stability of Cesium Metal Halide Perovskites

“…Using DFT, Kye et al also found α-CsPbI 3 to have a negative enthalpy of formation, though it was less negative than δ-CsPbI 3 , i.e., the α-polymorph is only metastable with respect to the δ-phase. 51 The low temperature heat capacity of CsPbI 3 was only reported from 0.4 up to 150 K by Evarestov et al 52 As a sidenote, the Cs 2 PbX 4 and CsPb 2 X 5 compounds, which were studied using time-dependent density functional theory (TD-DFT), do not exist as bulk compounds for X = I, 53 though there can be two-dimensional materials formed via nonambient pressure routes. 54 Compared to the two systems discussed in supra, practically nothing is known about the BiI 3 −PbI 2 system.…”

“…58 Kye et al found similar results. 51 For thin films, the metastability of α-CsPbI 3 with respect to δ-CsPbI 3 upon Bi 3+ -doping was also experimentally proven: above 393 K, the films turn into the δ-CsPbI 3 variant. 59 ■ METHODS Synthesis.…”