Effect of potassium precursor concentration on the performance of perovskite-sensitized solar cells

Metal doping into TiO₂ photoanode of the perovskite-sensitized solar cell (PSSC) is a technique to increase its photosensitivity, electrical conductivity, lifetime and charge transport. It is also to reduce recombination of photogenerated electrons and holes. This study reports the use of potassium-doped TiO₂ microtablet as a photoanode of PSSC. The effect of potassium content on the properties of K-doped TiO₂ and the performance parameter on the device has been investigated. The X-ray diffraction studies reveal that the dominant anatase phase exists in the sample without the presence of potassium phase, signifying that it is successfully doped into TiO₂. The morphology of the sample is microtablets, their size decreases with the concentration of K₂PtCl₄. The energy gap was found to increase with the doping content until its optimum content at 0.4 mM K₂PtCl₄. It is found that the photosensitivity of potassium-doped TiO₂ increases with the increase of potassium precursor concentration and optimum at the concentration of 0.4 mM corresponding with the power conversion efficiency of 5.71%. This is due to the lowest energy gap and charge transfer resistance. This is also due to the longest carrier lifetime and carrier transport time.