In this work, nickel sulphide (NiS)–reduced graphene oxide (rGO) (NiS–rGO) has been used as a cathode in dye-sensitized solar cell (DSSC). The cathode has been prepared via liquid phase deposition technique assisted with modified Hummer’s method and spin-coating technique. The effect of annealing temperature on the properties of NiS– rGO has been reported. The influence of temperature on performance of the device utilizing NiS–rGO cathode has also been investigated. The annealing temperature ranges from 320 to 400°C. The sample shows minor phase of NiS and rGO. The device using the cathode annealed at 380°C produced the best power conversion efficiency (${\eta}$) of 0.50%. This champion device also yielded the highest $V_{oc}$ of 0.72 V. This is because this device owns the lowest sheet resistance ($R_s$) of 11.50 ${\Omega}$ per square. The photovoltaic result of this work signifies that NiS–rGO has the potential as a substitution for platinum as cathode for DSSC.

Metal doping into TiO$_2$ 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 photogeneratedel ectrons and holes. This study reports the use of potassium-doped TiO$_2$ microtablet as a photoanode of PSSC. The effect of potassium content on the properties of K-doped TiO$_2$ 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 TiO$_2$. The morphology of the sample is microtablets, their size decreases with the concentration of K$_2$PtCl$_4$. The energy gap was found to increase with the doping content until its optimum content at 0.4 mM K$_2$PtCl$_4$. It is found that the photosensitivity of potassium-doped TiO$_2$ 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.