A simple engineering strategy with side chain liquid crystal polymers in perovskite absorbers for high efficiency and stability

Accomplishing a superior perovskite layer with better morphology, enhanced efficiency, and improved stability is one of the great challenges to researchers. In present work, we incorporated various side chain liquid crystal polymers (SCLCP) as dopants into the perovskite precursor to attain high efficiency and long-term stability of the perovskite solar cells (PSCs). Incorporation of SCLCP increases the grain size of the crystalline perovskite film by controlled solvent evaporation, decreased the grain boundaries and reduced charge recombination, which decelerates the material degradation. With the SCLCP doping, the PSC power conversion efficiency was expressively enhanced from 17.8% (non-doped) to 19.01% for the doped perovskite film with much improved stability. Furthermore, the atomic force microscopy measurements showed a better surface roughness for doped film by effective passivation of the perovskite grain surfaces. Field emission scanning electron microscope also showed better morphology with reduced grain boundaries. Especially, the SCLCP act as bridge between the crystal grains for efficient charge transfer from perovskite layer towards the electrode, which would moderately illustrate the increased efficiency and stability.