An Insight into Atmospheric Plasma Jet Modified ZnO Quantum Dots Thin Film for Flexible Perovskite Solar Cell: Optoelectronic Transient and Charge Trapping Studies

In this work, a new embodiment of flexible perovskite solar cell is based on graphene (Gr) as the barrier layer and the atmospheric plasma jet (APjet)-treated ZnO quantum dots (QDs) as the mesoscopic metal oxide layer on ITO-PET substrates. The ITO-PET flexible substrate was treated with oxygen (O-2) plasma before creating an efficient barrier layer of Gr, and thereafter as-synthesized ZnO QDs were deposited by spin coating on ITO-PET/Gr thin film. ITO-PET/Gr/ZnO-QDs thin film substrates were finally subjected to APjet treatment using RF power of similar to 40 W with frequency of similar to 13.56 MHz, which substantially improved the interfacial properties of the deposited layers. The fabricated ITO-PET/Gr/ZnO-QDs(APjet)/CH3NH3PbI3/spiro-MeOTAD/Ag flexible perovskite solar cell obtained the high conversion efficiency of similar to 9.73% along with high short circuit current (J(SC)) of similar to 16.8 mA/cm(2), open circuit voltage (V-OC) of similar to 0.935 V, and high fill factor (FF) of similar to 0.62. The APjet treatment on ITO-PET/Gr/ZnO QDs thin film enhanced the performances and the photocurrent density as compared to other solar cells fabricated without APjet treated ITO-PET/Gr/ZnO QDs thin film. By analyzing the intensity-modulated photocurrent (IMPS)/photovoltage spectroscopy (IMVS), the fabricated flexible perovskite solar cell exhibited a good charge transfer rate and a reduction in the recombination rate. The APjet treatment and the introduction of low-cost Gr barrier layer are promising prospects to approach low cost photovoltaic devices.