Supporting Information Electrodeposition of Epitaxial Lead Iodide and ...
Supporting Information
Electrodeposition of Epitaxial Lead Iodide and Conversion to Textured Methylammonium Lead Iodide Perovskite James C. Hill, Jakub A. Koza, and Jay A. Switzer* Department of Chemistry and Graduate Center for Materials Research, Missouri University of Science and Technology, Rolla, Missouri, 65409-1170, United States *correspondence to: [email protected]
Experimental Figure S1 – Crystal structure of PbI2 Figure S2 – Linear sweep voltammetry Figure S3 – EQCM data Figure S4 – XRD of FTO/PbI2 Figure S5 – SEM of FTO/PbI2 Figure S6 – Williamson-Hall plots of epitaxial PbI2 on single-crystal Au Figure S7 – SEM of electrodeposited epitaxial PbI2 on single-crystal Au Figure S8 –SEM and TEM of electrodeposited epitaxial PbI2 on single-crystal Au Figure S9 – Calculated x-ray pole figure for PbI2 Figure S10 – Single-crystal Au substrate x-ray pole figures Figure S11 – Single-crystal Au substrate and electrodeposited epitaxial PbI2 azimuthal scans Figure S12 – Coincidence lattice for unrotated Au(111)/PbI2
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Experimental: Synthesis – PbI2 - The lead iodide deposition solution was prepared by dissolving iodine (Sigma Aldrich, ≥99.8%) in ethanol, and dissolving lead nitrate (Sigma Aldrich, ≥99%) and sodium nitrate (Sigma Aldrich, reagent grade) in deionized (DI) water and adjusting the pH to 2 with nitric acid (Sigma Aldrich, 70%). Subsequently, these two solutions were combined for a final concentration of 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol. Fluorine-doped tin oxide (FTO) coated glass (Hartford TEC Glass Co Inc.) or single crystal gold substrates (Monocrystals Company) were used as the working electrode. Single-crystal gold substrates with [100], [110], and [111] orientations were prepared by electropolishing in a solution consisting of a 2:1:1 ratio of ethanol, ethylene glycol, and hydrochloric acid at a current density of 2.5 A/cm2 with stirring at 400 rpm and the heating element set to 100°C. After electropolishing, the single crystal gold substrates were annealed in a hydrogen flame. The counter electrode was a high surface area platinum coiled wire. An Ag/AgCl reference electrode was used for all electrochemical experiments. All electrodepositions were performed on a Metrohm Autolab PGSTAT30 potentiostat. CH3NH3PbI3 – Methylammonium lead iodide was synthesized by vapor assisted chemical transformation of a solid. Single crystal gold substrates with electrodeposited epitaxial PbI2 were heated in a tube furnace (Lindberg) with methylammonium iodide powder under Argon. The samples were inserted into the tube furnace downstream of the methylammonium iodide powder, which was vaporized during heating. The chamber was purged with Argon for 30 minutes prior to applying heat. The sample was held at 180 °C for two hours with a 2 °C/min ramp rate. The samples were stored in a desiccator after conversion to prevent decomposition due to humidity.
Characterization – Electrochemical quartz crystal microbalance data was collected using a Stanford Research Systems QCM200 digital controller, QCM25 crystal oscillator, and Ti/Au 5 MHz crystals. Xray diffraction (XRD) 2θ patterns were collected on a PANalytical X-Pert Pro Multi-purpose Diffractometer, and pole figure measurements were collected on a Philips X-Pert Materials Research Diffractometer, both with CuKα radiation. Scanning electron microscope images were taken using an FEI Helios NanoLab 600. High resolution TEM images were taken on a Tecnai F20. The cross-sectional TEM samples were prepared using the focused ion beam (FIB) to etch and an Omniprobe to lift out the sample in the FEI Helios NanoLab 600. CrystalMaker software was used to generate crystal structures, calculated x-ray diffraction patterns, and coincidence lattices. CaRIne crystallography software was used to generate calculated x-ray pole figure patterns.
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Figure S1. Lead iodide with P3ത m1 space group. The layered structure consists of PbI6 edge sharing clusters with octahedrally coordinated lead at the center and iodide atoms at the corners.
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Figure S2. Linear sweep voltammetry of solutions with 10 mM I2 in 66% ethanol (black), 5 mM Pb(NO3)2 and 100 mM NaNO3 in DI H2O (green), 10 mM I2 and 100 mM NaNO3 in 66% ethanol (blue), and 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol (red) collected at a 20 mV/s scan rate.
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Figure S3. Electrochemical quartz crystal microbalance analysis of PbI2 electrodeposited onto gold from a 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol solution at 0 V vs. Ag/AgCl until 0.5 C/cm2 of charge were passed. (a) Current density (black) is on the left y-axis and change in mass/cm2 (red) is on the right y-axis. (b) The left y-axis shows the total change in mass. Calculated change in mass based on total charge and 100% Faradaic efficiency (dashed) is compared to the change in mass experimentally measured by EQCM (solid). The right y-axis shows the time dependence of the Faradaic efficiency as lead cations are depleted.
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Figure S4. X-ray diffraction pattern of PbI2 on FTO, electrodeposited at -0.3 V vs. Ag/AgCl until 2.0 C/cm2 of charge were passed.
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Figure S5. Scanning electron microscopy images of PbI2 on FTO, electrodeposited at -0.3 V vs. Ag/AgCl until (a) 0.5 C/cm2 (b) and 2.0 C/cm2 of charge were passed.
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Figure S6. Williamson-Hall plots of PbI2 electrodeposited on single crystal (a) Au(100), (b) Au(110), and (c) Au(111) at 0 V vs. Ag/AgCl until 1.0 C/cm2 of charge were passed.
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a)
b)
c)
Figure S7. Scanning electron microscopy images of PbI2 on single crystal (a) Au(100), (b) Au(110), and (c) Au(111) electrodeposited at 0 V vs. Ag/AgCl until 1.0 C/cm2 of charge was passed.
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Figure S8. (a) Low magnification scanning electron microscopy of a coalesced film, and (b) corresponding transmission electron microscopy image of PbI2 on single-crystal Au(110) electrodeposited at 0 V vs. Ag/AgCl until 2.0 C/cm2 of charge was passed. The PbI2 film is continuous, and is approximately 670 nm thick.
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Figure S9. Calculated x-ray pole figure of PbI2 with P3ത m1 space group at 56.49° 2θ. The radial gridlines are at 30° tilt angle intervals.
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a)
b)
c)
Figure S10. X-ray pole figures analysis of single crystal gold substrates with PbI2 electrodeposited at 0 V vs. Ag/AgCl until 2.0 C/cm2 of charge were passed. (a) Au(100) measured at 64.576° 2θ, and (b) Au(110) measured at 44.392° 2θ. (c) Au(111) measured at 64.576° 2θ; the lower intensity spots are due to PbI2(0003) which overlaps with Au(111). The radial gridlines are at 30° tilt angle intervals.
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a)
d)
c)
b)
e)
f)
Figure S11. Azimuthal scans of PbI2 electrodeposited until 2.0 C/cm2 of charge were passed. (a) Au(100) was measured at 64.576° 2θ and a 45° tilt angle, and (b) Au(110) was measured at 44.392° 2θ and a 45° tilt angle. (c) Au(111) was measured at 64.576° 2θ and a 35° tilt angle; the lower intensity spots are due to PbI2(0003) which overlaps with Au(111). (d) PbI2 on Au(100) (e) PbI2 on Au(110), and (f) PbI2 on Au(111) were measured at 56.49° 2θ and a 45° tilt angle.
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Figure S12. Coincidence lattice of PbI2 electrodeposited on Au(111) with an epitaxial relationship of PbI2(0001)[11ത 00]//Au(111)[11ത 0]. Lead atoms are represented by the smaller red spots and gold atoms are represented by the larger blue spots.
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Electrodeposition of Epitaxial Lead Iodide and Conversion to Textured Methylammonium Lead Iodide Perovskite James C. Hill, Jakub A. Koza, and Jay A. Switzer* Department of Chemistry and Graduate Center for Materials Research, Missouri University of Science and Technology, Rolla, Missouri, 65409-1170, United States *correspondence to: [email protected]
Experimental Figure S1 – Crystal structure of PbI2 Figure S2 – Linear sweep voltammetry Figure S3 – EQCM data Figure S4 – XRD of FTO/PbI2 Figure S5 – SEM of FTO/PbI2 Figure S6 – Williamson-Hall plots of epitaxial PbI2 on single-crystal Au Figure S7 – SEM of electrodeposited epitaxial PbI2 on single-crystal Au Figure S8 –SEM and TEM of electrodeposited epitaxial PbI2 on single-crystal Au Figure S9 – Calculated x-ray pole figure for PbI2 Figure S10 – Single-crystal Au substrate x-ray pole figures Figure S11 – Single-crystal Au substrate and electrodeposited epitaxial PbI2 azimuthal scans Figure S12 – Coincidence lattice for unrotated Au(111)/PbI2
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Experimental: Synthesis – PbI2 - The lead iodide deposition solution was prepared by dissolving iodine (Sigma Aldrich, ≥99.8%) in ethanol, and dissolving lead nitrate (Sigma Aldrich, ≥99%) and sodium nitrate (Sigma Aldrich, reagent grade) in deionized (DI) water and adjusting the pH to 2 with nitric acid (Sigma Aldrich, 70%). Subsequently, these two solutions were combined for a final concentration of 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol. Fluorine-doped tin oxide (FTO) coated glass (Hartford TEC Glass Co Inc.) or single crystal gold substrates (Monocrystals Company) were used as the working electrode. Single-crystal gold substrates with [100], [110], and [111] orientations were prepared by electropolishing in a solution consisting of a 2:1:1 ratio of ethanol, ethylene glycol, and hydrochloric acid at a current density of 2.5 A/cm2 with stirring at 400 rpm and the heating element set to 100°C. After electropolishing, the single crystal gold substrates were annealed in a hydrogen flame. The counter electrode was a high surface area platinum coiled wire. An Ag/AgCl reference electrode was used for all electrochemical experiments. All electrodepositions were performed on a Metrohm Autolab PGSTAT30 potentiostat. CH3NH3PbI3 – Methylammonium lead iodide was synthesized by vapor assisted chemical transformation of a solid. Single crystal gold substrates with electrodeposited epitaxial PbI2 were heated in a tube furnace (Lindberg) with methylammonium iodide powder under Argon. The samples were inserted into the tube furnace downstream of the methylammonium iodide powder, which was vaporized during heating. The chamber was purged with Argon for 30 minutes prior to applying heat. The sample was held at 180 °C for two hours with a 2 °C/min ramp rate. The samples were stored in a desiccator after conversion to prevent decomposition due to humidity.
Characterization – Electrochemical quartz crystal microbalance data was collected using a Stanford Research Systems QCM200 digital controller, QCM25 crystal oscillator, and Ti/Au 5 MHz crystals. Xray diffraction (XRD) 2θ patterns were collected on a PANalytical X-Pert Pro Multi-purpose Diffractometer, and pole figure measurements were collected on a Philips X-Pert Materials Research Diffractometer, both with CuKα radiation. Scanning electron microscope images were taken using an FEI Helios NanoLab 600. High resolution TEM images were taken on a Tecnai F20. The cross-sectional TEM samples were prepared using the focused ion beam (FIB) to etch and an Omniprobe to lift out the sample in the FEI Helios NanoLab 600. CrystalMaker software was used to generate crystal structures, calculated x-ray diffraction patterns, and coincidence lattices. CaRIne crystallography software was used to generate calculated x-ray pole figure patterns.
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Figure S1. Lead iodide with P3ത m1 space group. The layered structure consists of PbI6 edge sharing clusters with octahedrally coordinated lead at the center and iodide atoms at the corners.
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Figure S2. Linear sweep voltammetry of solutions with 10 mM I2 in 66% ethanol (black), 5 mM Pb(NO3)2 and 100 mM NaNO3 in DI H2O (green), 10 mM I2 and 100 mM NaNO3 in 66% ethanol (blue), and 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol (red) collected at a 20 mV/s scan rate.
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Figure S3. Electrochemical quartz crystal microbalance analysis of PbI2 electrodeposited onto gold from a 10 mM I2, 5 mM Pb(NO3)2, and 100 mM NaNO3 in 66% ethanol solution at 0 V vs. Ag/AgCl until 0.5 C/cm2 of charge were passed. (a) Current density (black) is on the left y-axis and change in mass/cm2 (red) is on the right y-axis. (b) The left y-axis shows the total change in mass. Calculated change in mass based on total charge and 100% Faradaic efficiency (dashed) is compared to the change in mass experimentally measured by EQCM (solid). The right y-axis shows the time dependence of the Faradaic efficiency as lead cations are depleted.
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Figure S4. X-ray diffraction pattern of PbI2 on FTO, electrodeposited at -0.3 V vs. Ag/AgCl until 2.0 C/cm2 of charge were passed.
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Figure S5. Scanning electron microscopy images of PbI2 on FTO, electrodeposited at -0.3 V vs. Ag/AgCl until (a) 0.5 C/cm2 (b) and 2.0 C/cm2 of charge were passed.
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Figure S6. Williamson-Hall plots of PbI2 electrodeposited on single crystal (a) Au(100), (b) Au(110), and (c) Au(111) at 0 V vs. Ag/AgCl until 1.0 C/cm2 of charge were passed.
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a)
b)
c)
Figure S7. Scanning electron microscopy images of PbI2 on single crystal (a) Au(100), (b) Au(110), and (c) Au(111) electrodeposited at 0 V vs. Ag/AgCl until 1.0 C/cm2 of charge was passed.
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Figure S8. (a) Low magnification scanning electron microscopy of a coalesced film, and (b) corresponding transmission electron microscopy image of PbI2 on single-crystal Au(110) electrodeposited at 0 V vs. Ag/AgCl until 2.0 C/cm2 of charge was passed. The PbI2 film is continuous, and is approximately 670 nm thick.
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Figure S9. Calculated x-ray pole figure of PbI2 with P3ത m1 space group at 56.49° 2θ. The radial gridlines are at 30° tilt angle intervals.
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a)
b)
c)
Figure S10. X-ray pole figures analysis of single crystal gold substrates with PbI2 electrodeposited at 0 V vs. Ag/AgCl until 2.0 C/cm2 of charge were passed. (a) Au(100) measured at 64.576° 2θ, and (b) Au(110) measured at 44.392° 2θ. (c) Au(111) measured at 64.576° 2θ; the lower intensity spots are due to PbI2(0003) which overlaps with Au(111). The radial gridlines are at 30° tilt angle intervals.
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a)
d)
c)
b)
e)
f)
Figure S11. Azimuthal scans of PbI2 electrodeposited until 2.0 C/cm2 of charge were passed. (a) Au(100) was measured at 64.576° 2θ and a 45° tilt angle, and (b) Au(110) was measured at 44.392° 2θ and a 45° tilt angle. (c) Au(111) was measured at 64.576° 2θ and a 35° tilt angle; the lower intensity spots are due to PbI2(0003) which overlaps with Au(111). (d) PbI2 on Au(100) (e) PbI2 on Au(110), and (f) PbI2 on Au(111) were measured at 56.49° 2θ and a 45° tilt angle.
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Figure S12. Coincidence lattice of PbI2 electrodeposited on Au(111) with an epitaxial relationship of PbI2(0001)[11ത 00]//Au(111)[11ത 0]. Lead atoms are represented by the smaller red spots and gold atoms are represented by the larger blue spots.
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