Supporting Information

Transcription

1 Supporting Information Aqueous, screen-printable paste for fabrication of mesoporous composite anatase-rutile TiO 2 nanoparticle thin films for (photo)electrochemical devices Amrita Yasin, Fuqiang Guo, George P. Demopoulos* Department of Mining and Materials Engineering, McGill University *Corresponding author. george.demopoulos@mcgill.ca Number of pages: 15 Number of figures: 7 Number of tables: 3

2 This document provides supporting information to the article, Aqueous, screen-printable paste for fabrication of mesoporous composite anatase-rutile TiO 2 nanoparticle thin films for (photo)electrochemical devices. Figure S1 presents X-Ray diffraction (XRD) patterns of the aqueous synthesized anatase (JCPDS ) and rutile (JCPDS ) [1] used in the paste formulation, while Table S1 lists the BET (Brunauer-Emmett-Teller) surface area and Figure S2 presents the SEM and TEM images of the particles. Figure S3 presents the J-V curves of dye-sensitized solar cells (DSSCs) assembled from TiO 2 powder and colloid, using the organic-medium protocol; the photovoltaic parameters are presented in Table 1 of the article. Figure S4 presents the thermogravimetric (TGA) analysis of Paste U7 showing ~20% TiO 2 loading. Table S2 (a) presents data corresponding to BJH (Barrett-Joyner-Halenda) desorption pore size distribution, and Table S2 (b) presents N 2 adsorption/desorption data used to determine BET (Brunauer Emmett Teller) surface area; the corresponding isotherms and pore size distribution curves are presented in Figure 5 of the manuscript. Figure S5 presents the cumulative pore volume determined through BJH desorption pore distribution analysis. Figure S6 presents the J-V curves of DSSCs presented in Table 4 of the article. Figure S7 (a) presents efficiency and adsorbed dye as a function of pore width, and Figure S7 (b) presents efficiency and adsorbed dye as a function of surface area for the sintered films. Both curves show no direct relationship between efficiency and dye adsorption. Table S3 (a) lists additional paste formulations that were fabricated and Table S3 (b) presents the photovoltaic parameters of the respective pastes. Addition of polyacrylic acid or Triton-X did not improve the photovoltaic performance (Paste V1, V2, V3). Paste U9 was constructed using ethanol as the only solvent to observe if using a solution of water and ethanol has an adverse effect. The efficiency obtained was 4.5%, while the efficiency obtained for Paste U7 (as listed in Table 4 of the article) was 4.43%. The efficiencies are similar, even as less ethanol is used in the proposed protocol. S1

3 Figure S1: (a) XRD pattern of anatase (b) XRD pattern of rutile Table S1: BET surface area and calculated equivalent primary particle diameter Anatase Rutile Surface area (m 2 /g) Equivalent primary particle size (nm) S2

4 Figure S2: (a) SEM image of dry anatase (b) TEM image of dry anatase (c) SEM image of dry rutile (d) TEM image of dry rutile. S4

5 Current (ma/cm 2 ) J-V comparison of Powder & Gel DSSCs η=4.42% η=4.85% Voltage (V) Powder Gel Figure S3: Comparison of DSSC performance of cells made from TiO 2 powder and TiO 2 colloid following organic protocol Figure S4: A representative TGA conducted to determine TiO 2 loading (Paste U7) S4

6 Table S2 (a): Tabular data corresponding to BJH desorption pore size distribution. Paste U4, 0 g PEG (cm³/g) (cm³/g) Area (m²/g) Area(m²/g) Width Range (Å) Average Width (Å) Paste U2, 1 g PEG (cm³/g) (cm³/g) Area (m²/g) Area(m²/g) Width Range (Å) Average Width (Å) S5

7 Paste T1, 1.5 g PEG (cm³/g) (cm³/g) Area (m²/g) Area(m²/g) Width Range (Å) Average Width (Å) S6

8 Paste U7, 2 g PEG (cm³/g) (cm³/g) Area (m²/g) Area(m²/g) Width Range (Å) Average Width (Å) Paste U5, 2.5 g Width Range (Å) Average Width (Å) Area (m²/g) Area(m²/g) S7

9 (cm³/g) (cm³/g) (b) N 2 adsorption/desorption data used for BET surface area analysis Relative Pressure (p/p ) Paste U4, 0 g PEG Absolute Quantity Pressure Adsorbed (mmhg) (cm³/g STP) Relative Pressure (p/p ) Paste U2, 1 g PEG Absolute Quantity Pressure Adsorbed (mmhg) (cm³/g STP) S8

10 S9

11 Relative Pressure (p/p ) Paste T1, 1.5 g PEG Absolute Quantity Pressure Adsorbed (mmhg) (cm³/g STP) Relative Pressure (p/p ) Paste U7, 2 g PEG Absolute Quantity Pressure Adsorbed (mmhg) (cm³/g STP) S10

12 Paste U5, 2.5 g PEG Relative Pressure (p/p ) Absolute Pressure (mmhg) Quantity Adsorbed (cm³/g STP) S11

13 S12

14 pore volume (cm 3 /g) (U4) (U2) (T1) (U7) (U5) PEG quantity (g) Figure S5: pore volume as a function of PEG quantity for the sintered films J-V curves of DSSCs Current (ma/cm 2 ) U7 U5 U4 U2 T Voltage (V) Figure S6: J-V curves of DSSC assembled from photoanode films prepared from variable PEG amount paste formulation. S13

15 a" Efficiency (%) Efficiency & Adsorbed Dye vs. Width E g 2.5g 2g g g Width (Å) 6.50E E E E E E E E E-05 Adsorbed Dye (mol/cm 3 ) Efficiency Adsorbed dye b" Efficiency (%) g Efficiency & Adsorbed Dye vs. BET Surface Area 2g 2.5g 0g 1.5g 7.00E E E E E E E E E E BET Surface Area (m 2 /g) Adsorbed Dye (mol/cm 3 ) Efficiency Adsorbed dye Figure S7: (a) Efficiency and dye loading as a function of pore width, (b) Efficiency and dye loading as a function of surface area; (amount of PEG is given next to each data point): 3g TiO 2 (Anatase 80%, Rutile 20%), 0.5mL Acetic acid, 10g PG, 50mL Water, 50mL Ethanol. S14

16 Table S3: (a) Additional paste formulations Paste PEG PG Additional component Quantity (g) Quantity (g) Component Quantity V Polyacrylic acid 2g V Triton-X 800 µl V Triton-X 400 µl U9* *For U9, 95% ethanol, 5% water (volume basis) was used as solvent (b) Photovoltaic parameters corresponding to additional paste formulations Paste Thickness (µm) η (%) V oc (V) J sc (ma/cm 2 ) FF V V V U References 1. Charbonneau, C.; Gauvin, R.; Demopoulos, G.P. Aqueous Solution Synthesis of Crystalline Anatase Nanocolloids for the Fabrication of DSC Photoanodes. JES (3): p. H224-H231. S15