The role of hafnium acetylacetonate buffer layer on the performance of lead halide perovskite solar cells derived from dehydrated lead acetate as Pb source

Abstract

In this research, we demonstrated the use of hafnium acetylacetonate (Hfaca) dissolved in ethanol as a buffer layer for perovskite solar cells from non-halide Pb (dehydrated lead acetate) source material. The inverted p-i-n planar heterojunction structure was employed in this work. A one step spin-coating method was used in depositing the perovskite solution before thermal annealing at 90 ○C for 5 min to form the perovskite film. Hfaca has been previously used as a buffer layer, but the optimal concentration has not been reported. The optimum concentration of Hfaca was found to be 1.0 mg/ml, resulting in a power conversion efficiency (PCE) of 12.23% corresponding to more than 30% improvement when compared to the control device (phenyl-C61-butyric acid methyl ester/Ag) without Hfaca, which has a PCE of 8.89%. Hfaca as a buffer layer leads to superior stability, retaining about 90% of its original PCE values after 15 days of storage in a glove box, compared to the control device, which retains 70% of the initial PCE value under the same storage