Enhanced power conversion efficiency and preferential orientation of the MAPbI3 perovskite solar cells by introduction of urea as additive

In this investigation, urea (NH2CONH2) was added into the perovskite precursor solution with Pb(CH3COO)3 as precursor. The effects of the urea content in the solution on the crystallization dynamics and the orientation of the perovskite films, and their photovoltaic properties were investigated. The results showed that the optimal annealing duration for the perovskite film increased with the urea content in the solution. An interaction between the urea and the source materials was observed. As a result, urea addition in the Pb(CH3COO)3 based solution has an effect on the crystallization rate and the grain size of the perovskite phase. We found that the suitable amount of urea in the solution was beneficial for the formation of highly (110)-oriented perovskite films and this resulted in the corresponding solar cells with enhanced power conversion efficiency of nearly 17%.