RF sputtered ti layer for flexible perovskite solar cells

In this work, the effects of a titanium (Ti) layer on the charge transport and recombination rates of flexible perovskite solar cells are studied. Ti as an efficient barrier layer is deposited directly on PET-ITO flexible substrates through RF magnetic sputtering using a Ti-source and a pressure of ~5 mTorr. A Ti coated PET-ITO is used for the fabrication of a flexible perovskite solar cell without using any metal oxide layer. The fabricated flexible perovskite solar cell is composed of a PET-ITO/Ti/perovskite (CH₃NH₃PbI₃)/organic hole transport layer of 2,2',7,7'-tetrakis [N, N’-di-pmethoxyphenylamine]- 9,9'-spirobifluorene (spiro-OMeTAD)-Li-TFSI/Ag. A high conversion efficiency of ~8.39% along with a high short circuit current (JSC) of ~15.24 mA cm^-2, an open circuit voltage (VOC) of ~0.830 V and a high fill factor (FF) of ~0.66 are accomplished by the fabricated flexible perovskite solar cell under a light illumination of ~100 mWcm^-2 (1.5 AM). Intensity-modulated photocurrent (IMPS)/photovoltage spectroscopy (IMVS) studies demonstrates that the fabricated flexible perovskite solar cell considerably reduces the recombination rate.