Design of High-Performance Lead-Free Quaternary Antiperovskites for Photovoltaics via Ion Type Inversion and Anion Ordering

Abstract

The emergence of halide double perovskites significantly increases the compositional space for lead-free and air-stable photovoltaic absorbers compared to halide perovskites. Nevertheless, most halide double perovskites exhibit oversized band gaps (>1.9 eV) or dipole-forbidden optical transition, which are unfavorable for efficient single-junction solar cell applications. The current device performance of halide double perovskite is still inferior to that of lead-based halide perovskites, such as CH3NH3PbI3 (MAPbI3). Here, by ion type inversion and anion ordering on perovskite lattice sites, two new classes of pnictogen-based quaternary antiperovskites with the formula of X6B2AA′ and X6BB′A2 are designed. Phase stability and tunable band gaps in these quaternary antiperovskites are demonstrated based on first-principles calculations. Further photovoltaic-functionality-directed screening of these materials leads to the discovery of 5 stable compounds (Ca6N2AsSb, Ca6N2PSb, Sr6N2AsSb, Sr6N2PSb, and Ca6NPSb2) with suitable direct band gaps, small carrier effective masses and low exciton binding energies, and dipole-allowed strong optical absorption, which are favorable properties for a photovoltaic absorber material. The calculated theoretical maximum solar cell efficiencies based on these five compounds are all larger than 29%, comparable to or even higher than that of the MAPbI3 based solar cell. Our work reveals the huge potential of quaternary antiperovskites in the optoelectronic field and provides a new strategy to design lead-free and air-stable perovskite-based photovoltaic absorber materials.

Antiperovskite Sr3MN and Ba3MN (M = Sb or Bi) as promising photovoltaic absorbers for thin‐film solar cells: A first‐principles study

“…Inorganic antiperovskite nitrides with X 3 AN formula (X is a divalent cation and A is a trivalent anion) are emerging compound semiconductors with a potential application in solar‐energy conversion 24,32,33 . To enable the potential application, an understanding of the fundamental properties relevant for PV applications is important, but it has not been established yet.…”

“…31 Inorganic antiperovskite nitrides with X 3 AN formula (X is a divalent cation and A is a trivalent anion) are emerging compound semiconductors with a potential application in solar-energy conversion. 24,32,33 To enable the potential application, an understanding of the fundamental properties relevant for PV applications is important, but it has not been established yet. In this study, using density functional theory (DFT) calculations, we scrutinize the crystal structure, electronic band structure, and optical absorption of Sr 3 MN and Ba 3 MN (M = Sb or Bi), potential PV absorbers.…”

Structure–Composition–Property Relationships in Antiperovskite Nitrides: Guiding a Rational Alloy Design

“…For example, there are 3, 6, and 3 different configurations for x = 0.25, 0.50, and 0.75 (see Figure a–c), respectively. The total energy difference between different configuration is smaller than 11 meV/atom, suggesting the possibility of forming disordered solid solutions . It is shown that although the band gap differs between different configurations for a certain x , the band gap of Mg 3 NAs 1– x Bi x alloys generally decreases with increasing x , reduced from 2.102 eV in Mg 3 NAs to 0.612 eV in Mg 3 NBi (see Figure d).…”

“…The total energy difference between different configuration is smaller than 11 meV/atom, suggesting the possibility of forming disordered solid solutions. 46 It is shown that although the band gap differs between different configurations for a certain x, the band gap of Mg 3 NAs 1−x Bi x alloys generally decreases with increasing x, reduced from 2.102 eV in Mg 3 NAs to 0.612 eV in Mg 3 NBi (see Figure 6d). This decreasing trend is associated with the higher Bi p orbitals than As p orbitals.…”

Theoretical Prediction of Mixed-Valence Layered Halide Perovskites Cs4M(IV)M(II)2X12 (M = Ge, Sn; X = Cl, Br)

“…33 In addition, the calculated static dielectric constant and optical absorption coefficient of Cs 4 GeGe 2 Br 12 are close to those typical of double perovskites (e.g., Cs 2 AgBiBr 6 ). 14 We believe that our work expands the family of mixed-valence halide perovskites and provides a new idea for potential optoelectronic semiconductor design.…”