Perovskite film-wire transformation: preparation, characterization and device application

We demonstrate regular-type perovskite solar cells based on tungsten trioxide nanoparticles layer (WO3 NL) as the electron transport layer and methylammonium lead iodide nanowires (MAPbI3 NWs) as the absorbing layer. By adjusting the amount of the anti-solvent DMF, MAPbI3 NWs with different diameters ranging from 50 to 100 nm and lengths extending to several micrometers were obtained. [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and cesium carbonate (Cs2CO3) were introduced between WO3 NL and MAPbI3 NWs to improve film morphology and charge transfer ability. Meanwhile, spiro-MeOTAD doped with bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) was utilized to enhance hole transport. Finally, the perovskite solar cells with the configuration of ITO/WO3 NL/Cs2CO3/PCBM/MAPbI3 NWs/spiro-MeOTAD/Au were fabricated and evaluated. To date, perovskite NWs treating with the proper amount of the anti-solvent DMF possess higher absorption, faster carrier transportation and lower recombination that are responsible for photovoltaic application.