Polystyrene stabilized perovskite component, grain and microstructure for improved efficiency and stability of planar solar cells

Polystyrene (PS) is introduced to stabilize the perovskite component, grains and microstructures by forming PS-capped perovskite grains. It is found that the PS coverage has significant advantages in suppressing the component loss and phase separation, obstructing moisture corrosion and promoting crystal self-healing of perovskite films. Besides, with the PS involvement, exceeding 20% efficiency of a planar TiO2 based cell has been achieved by decreasing charge traps and nonradiative recombination.