Starting materials: [AE2T].2HI (synthesized), BiI3, AgI, hydriodic acid (58 wt. % in H2O)

Product: dark red [AE2T]2AgBiI8 single crystals

Description: Stoichiometric quantities of [AE2T].2HI (7.8 μmoles), BiI3 (3.9 μmoles) and AgI (3.9 μmoles) were dissolved in a mixture of 0.5 ml hydriodic acid (58 wt. % in H2O) and 2 ml deionized water at 100° C for 30 min. The solution was then slowly cooled to room temperature over 60 hrs. The as-obtained dark red crystals (~ 82 % yield) were filtered, washed with copious amounts of diethyl ether, dried in vacuum and stored in a N2 glove box for further characterization.

Method: Single crystal X-ray diffraction

Description: SC-XRD was performed with Mo-Kα radiation (λ=0.710 Å) using a Bruker APEX II CCD diffractometer operating at 50 kV and 30 mA.

• Rayan C Duke University

Starting materials: [AE2T].2HI (synthesized), BiI3, AgI, hydriodic acid (58 wt. % in H2O)

Product: dark red [AE2T]2AgBiI8 single crystals

Description: Stoichiometric quantities of [AE2T].2HI (7.8 μmoles), BiI3 (3.9 μmoles) and AgI (3.9 μmoles) were dissolved in a mixture of 0.5 ml hydriodic acid (58 wt. % in H2O) and 2 ml deionized water at 100° C for 30 min. The solution was then slowly cooled to room temperature over 60 hrs. The as-obtained dark red crystals (~ 82 % yield) were filtered, washed with copious amounts of diethyl ether, dried in vacuum and stored in a N2 glove box for further characterization.

Method: Single crystal X-ray diffraction

Description: SC-XRD was performed with Mo-Kα radiation (λ=0.710 Å) using a Bruker APEX II CCD diffractometer operating at 50 kV and 30 mA.

• Rayan C Duke University

Starting materials: [AE2T].2HI, BiI3, Ag, hydriodic acid (58 wt. % in H2O), anhydrous dimethylformamide

Product: [AE2T]2AgBiI thin film

Description: Stoichiometric amounts of [AE2T].2HI (0.024 mmoles), BiI3 (0.012 mmoles) and AgI (0.012 mmoles) were dissolved in a mixture of 0.5 ml hydriodic acid (58 wt. % in H2O) and 4 ml deionized water at 100° C for 30 min. The solution was cooled to room temperature and the resulting dark red precipitate was collected by centrifugation, washed with diethyl ether, and dried in vacuum. The solid powder was dissolved in 80 μL of anhydrous dimethylformamide. 40 μL of the solution was spin-coated on pre-cleaned glass substrates at a spin speed of 1500 RPM for 30 s, and annealed at 150° C on a hot plate for 10 min in a N2-filled glove box.

Method: UV-vis absorption

Description: Shimadzu UV-3600 UV−vis-NIR spectrophotometer

• Rayan C Duke University

Starting materials: [AE2T].2HI, BiI3, Ag, hydriodic acid (58 wt. % in H2O), anhydrous dimethylformamide

Product: [AE2T]2AgBiI thin film

Description: Stoichiometric amounts of [AE2T].2HI (0.024 mmoles), BiI3 (0.012 mmoles) and AgI (0.012 mmoles) were dissolved in a mixture of 0.5 ml hydriodic acid (58 wt. % in H2O) and 4 ml deionized water at 100° C for 30 min. The solution was cooled to room temperature and the resulting dark red precipitate was collected by centrifugation, washed with diethyl ether, and dried in vacuum. The solid powder was dissolved in 80 μL of anhydrous dimethylformamide. 40 μL of the solution was spin-coated on pre-cleaned glass substrates at a spin speed of 1500 RPM for 30 s, and annealed at 150° C on a hot plate for 10 min in a N2-filled glove box.

Method: UV-vis absorption

Description: Shimadzu UV-3600 UV−vis-NIR spectrophotometer

• Rayan C Duke University

Starting materials: [AE2T].2HI, BiI3, Ag, hydriodic acid (58 wt. % in H2O), anhydrous dimethylformamide

Product: [AE2T]2AgBiI thin film

Description: Stoichiometric amounts of [AE2T].2HI (0.024 mmoles), BiI3 (0.012 mmoles) and AgI (0.012 mmoles) were dissolved in a mixture of 0.5 ml hydriodic acid (58 wt. % in H2O) and 4 ml deionized water at 100° C for 30 min. The solution was cooled to room temperature and the resulting dark red precipitate was collected by centrifugation, washed with diethyl ether, and dried in vacuum. The solid powder was dissolved in 80 μL of anhydrous dimethylformamide. 40 μL of the solution was spin-coated on pre-cleaned glass substrates at a spin speed of 1500 RPM for 30 s, and annealed at 150° C on a hot plate for 10 min in a N2-filled glove box.

• Rayan C Duke University

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.025 eV

• Rayan C Duke University

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: PBE+TS

K-point grid: 2x5x5

Level of relativity: atomic ZORA

Basis set definition: NAO

Numerical accuracy: 0.005 eV/Angstrom

• Xixi Qin Duke University

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.05 eV

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.05 eV

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.05

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: PBE

K-point grid: 30x30x30

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.05 eV

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: PBE

K-point grid: 30x30x30

Level of relativity: 2nd variational non-self-consistent SOC

Basis set definition: NAO

Numerical accuracy: 0.05 eV

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: density functional theory

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: atomic ZORA with spin-orbit coupling

Basis set definition: FHI-aims tight

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: density functional theory

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

K-point grid: 3x3x3

Level of relativity: atomic ZORA with spin-orbit coupling

Basis set definition: FHI-aims tight

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: DFT

Exchange-correlation functional: PBE

K-point grid: 8*8*8

Level of relativity: atomic ZORA with SOC

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: Wien2K

Level of theory: DFT

Exchange-correlation functional: PBE

K-point grid: 1000

Level of relativity: Koelling-Harmon approximation + SOC

Geometry used in the calculation

• Ruyi Song Chemistry department, Duke university

Code: FHI-aims

Level of theory: density functional theory

Exchange-correlation functional: HSE06 α = 0.25, ω = 0.11/bohr

Level of relativity: atomic ZORA with spin-orbit-coupling

Basis set definition: tight

• Rayan C Duke University