Characterization of the Pore Filling of Solid State Dye Sensitized Solar Cells with Photoinduced Absorption Spectroscopy

Figure 7

(a) Δ𝑇𝑇⁻¹ signal intensities relative to the peak at 1450 nm, for 565 nm ((Δ𝑇_565nm𝑇_565nm⁻¹)/(Δ𝑇_1450nm𝑇_1450nm⁻¹), 𝑦-axis) compared to 825 nm ((Δ𝑇_825nm𝑇_825nm⁻¹)/(Δ𝑇_1450nm𝑇_1450nm⁻¹), 𝑥-axis). The solid line is a linear fit to the data, excluding the highly scattering points at the lowest concentration: 𝑦=−2.2𝑥+0.5. The dashed line shows 𝑦=−2.4𝑥+0.55. (b) The ln(relative PIA signal at 825 nm)/2.3 is plotted against the concentration times length (mol cm L⁻¹). The spiro-MeOTAD concentrations are 45 (▴), 90 (▾), 100 (♦) mg mL⁻¹; 180 (○) mg mL⁻¹; 200 (▵) mg mL⁻¹. Inset: Δ𝑇𝑇⁻¹ signal intensity relative to the peak at 1450 nm, for 825 nm ((Δ𝑇_825nm𝑇_825nm⁻¹)/(Δ𝑇_1450nm𝑇_1450nm⁻¹), ■) and for 565 nm ((Δ𝑇_565nm𝑇_565nm⁻¹)/(Δ𝑇_1450nm𝑇_1450nm⁻¹), (▿) compared to the filling fraction obtained in Section 2.1. The data are fitted with exponential functions: 𝑦=−2∗exp(−𝑥/0.1)+1.1(solidline)and−1∗exp(−𝑥/0.1)+0.75.

(a)

(b)