Zwitterions in 3D Perovskites: Organosulfide-Halide Perovskites

Abstract

Although sulfide perovskites usually require high-temperature syntheses, we demonstrate that organosulfides can be used in the milder syntheses of halide perovskites. The zwitterionic organosulfide, cysteamine (CYS; +NH3(CH2)2S–), serves as both the X– site and A+ site in the ABX3 halide perovskites, yielding the first examples of 3D organosulfide-halide perovskites: (CYS)PbX2 (X– = Cl– or Br–). Notably, the band structures of (CYS)PbX2 capture the direct bandgaps and dispersive bands of APbX3 perovskites. The sulfur orbitals compose the top of the valence band in (CYS)PbX2, affording unusually small direct bandgaps of 2.31 and 2.16 eV for X– = Cl– and Br–, respectively, falling in the ideal range for the top absorber in a perovskite-based tandem solar cell. Measurements of the carrier dynamics in (CYS)PbCl2 suggest carrier trapping due to defects or lattice distortions. The highly desirable bandgaps, band dispersion, and improved stability of the organosulfide perovskites demonstrated here motivate the continued expansion and exploration of this new family of materials, particularly with respect to extracting photocurrent. Our strategy of combining the A+ and X– sites with zwitterions may offer more members in this family of mixed-anion 3D hybrid perovskites.

Heteroanionic LaBrVIO4 (VI = Mo, W): Excellence in Both Nonlinear Optical Properties and Photoluminescent Properties

“…Heteroanionic compounds, which constitute two or more different anions, have attracted growing interest due to their structural flexibility and emerging physical properties, including nonlinear optical (NLO) properties, − superconducting properties, − photoluminescent response, − and thermoelectric properties, − etc. Heteroanionic compounds are different from polyanionic compounds, where there are anion–anion interactions existing within polyanionic clusters such as polyanionic [PO 4 ] 3– . ,− Heteroanionic compounds do not contain direct anion–anion interactions.…”

Thiocyanate-Stabilized Pseudo-cubic Perovskite CH(NH2)2PbI3 from Coincident Columnar Defect Lattices

“…Zwitterionic cysteammonium substitutes for both cation and anion in MAPbCl 3 and MAPbBr 3 but without crystallographic order. 39 Understanding how "too large" (e.g., relative to the Goldschmidt tolerance factor 12,40 ) ions become accommodated (or not) into the crystal structures and influence properties remains an important challenge in these emerging materials that warrants deeper investigations. This is particularly interesting for isovalent ion substitutions (e.g., SCN − for I − and hydroxylammonium for methylammonium) in contrast to aliovalent substitutions (e.g., ethylene diammonium for methylammonium).…”

“…Thioethylammonium and hydroxylammonium − are incorporated into MASnI 3 and MAPbI 3 , with partial order, such that ordered vacancies appear with high substitution amounts (>60%) to create a √5 a p × √5 a p × a p superstructure ( a p : cell parameter of primitive, P m 3̅ m , perovskite cell). Zwitterionic cysteammonium substitutes for both cation and anion in MAPbCl 3 and MAPbBr 3 but without crystallographic order . Understanding how “too large” (e.g., relative to the Goldschmidt tolerance factor , ) ions become accommodated (or not) into the crystal structures and influence properties remains an important challenge in these emerging materials that warrants deeper investigations.…”

Quartz‐Like Structure, Optical Activity, and High Stability in the First Chiral Cation‐Coordinated Perovskite Semiconductor

“…This is similar to a recent report by Karunadasa and co‐workers, who utilized a zwitterionic molecule containing sulfur to synthesize a PbS coordinated hybrid perovskite. [ 39 ] The cation‐coordination perovskites (CCPs) are a new type of structure in which the coordination atom in the cation replaces one halogen position in the lead‐halogen octahedron ( Figure ). As a result, they can show much‐improved stability compared to conventional ionic‐type perovskites while still maintaining similar semiconductor properties.…”