Solution-processed quantum dot SnO_(2) as an interfacial electron transporter for stable fully-air-fabricated metal-free perovskite solar cells

Perovskite solar cells could strongly compete with the silicon solar cells in the market soon as illustrated in recent studies.In this work,promising and stable metal-free perovskite solar cells(PSCs)has been successfully fabricated using an inorganic SnO_(2)/Quantum dot SnO_(2)(QD-SnO_(2))double layer as an efficient electron transport layer via a low-temperature solution process.The fully-air fabricated PSCs in the form of FTO/SnO_(2)/QD-SnO_(2)/CH3NH3PbI3/Carbon were tested at different annealed QD-SnO_(2) between 300 and 500℃.The as-prepared QD-SnO_(2) and the fabricated devices are characterized by various techniques,including XRD,XPS,HR-TEM,FE-SEM,UVeviseNIR spectroscopy,PL,and solar simulator.The prepared QD-SnO_(2) at 300℃ has shown well-ordered nanoparticles of 5.6 nm in diameter with superior carrier density(1.5×10^(15) cm^(-3))and highest carrier mobility(64.1 cm^(2)·V^(-1)·s^(-1)),accelerating the carriers separation process within the cell.The best devices demonstrated a maximum power conversion effi-ciency(PCE)of 11.7%,VOC 0.81 V,JSC 19.5 mA·cm^(-2),and FF 74%.The presence of an interfacial layer of QDSnO_(2) over the blocking SnO_(2) upsurges the band gaps alignment and accelerates the carriers extraction rate affecting the performance of the fabricated perovskite devices.Moreover,the optimized fabricated devices revealed a shelf stability-life of four months in humid air(40%-50%)with>83%of its initial PCE.This simple synthetic approach can develop the opportunities to transfer the cell from the lab to the market,which will be compatible with large-scale production.