Surface-activation modified perovskite crystallization for improving photovoltaic performance

An improved vapor-phase deposition that leveraged the use of surface activation of PbI 2 film has been developed for modifying perovskite crystallization process . This was achieved by loading Cl − ligands on closely-packed PbI 2 particle film—a scaffold that allowed in situ formation of perovskite active layer . The introducing of Cl − ligands served the Cl-capped and thus electrostatically-charged PbI 2 nanoparticles showed improved colloidal stability in DMF , which facilitated the preparation of PbI 2 film. More importantly, during the process of CH 3 NH 3 I (MAI) deposition i.e. the growth of perovskite materials, the presence of three-dimensional Cl − ligand matrix favored the formation of dense perovskite film. Moreover, a desired release of chloride was also achieved, thus promote the rearrangement of the perovskite during the volume expansion process. This finally led to a PCE of PSCs exceeding 16.42% under AM 1.5 irradiation. Therefore, surface-activation with Cl-ligand matrix could provide guidelines for the morphology optimization and the perovskite devices performance enhancement.