Influence of Poly(N-vinylcarbazole) as a Photoanode Component in Enhancing the Performance of a Dye-Sensitized Solar Cell

Increasing the dye adsorption and minimization of charge recombination are pivotal in improving the efficiency of a dye-sensitized solar cells (DSSCs). In the present investigation, these two effects have been accomplished through the introduction of poly( N -vinylcarbazole) (PVK) as an auxiliary component of the TiO 2 photoanode in a N719 dye-based DSSC. TiO 2 /PVK hybrid nanocomposites were prepared by simple blending of TiO 2 with small quantities of PVK (0.3–1.3 wt %) in the presence of PEG 20000, acetylacetone, and Triton X-100. X-ray diffraction data revealed that the crystalline properties of TiO 2 were not altered by the presence of PVK. The porosity and surface roughness of TiO 2 were enhanced by the addition of PVK. Spin-coated TiO 2 –PVK nanocomposite films showed highly enhanced dye adsorption in comparison to pristine TIO 2 films which had been attributed to an increase in the basicity of the TiO 2 surface. The N719 dye-sensitized TiO 2 /PVK photoanodes were assessed for their performance in a DSSC assembled with the I – /I 3 – redox electrolyte and sputtered Pt as counter electrode. The quantity of PVK in the nanocomposite was optimized by evaluating the photovoltaic performance. A maximum power conversion efficiency of 7.10% was achieved with a 0.9 wt % PVK loaded TiO 2, which was 58% greater than that of the pristine TiO 2 cell (4.48%). Impedance data showed a very low charge-transfer resistance of 3.79 Ω and a high electron lifetime of 31.41 ms, implying an effective reduction in the back electron transfer.