Hydrophobic compressed carbon/graphite based long-term stable perovskite solar cells

Abstract

Carbon/graphite nanocomposite (CGn) film had been employed as cathode for hole transport layer (HTL) free, mesoscopic, heterojunction perovskite solar cells (PSCs). Hydrophobic CGn film shows impressive charge transport characteristics that makes it promising candidate for cathode in HTL free PSCs. The electrochemical impedance spectroscopy measurements realised the significant charge transport characteristics can get for (10 μm–14 μm) thin film. On the other hand, the hydrophobic (Contact Angle 126°) CGn film after compression by 160 kPa pressure, become nearly superhydrophobic (Contact Angle 140°) greatly improve the conductivity of electrode 3x fold from 0.75 S/cm to 2.25 S/cm and subsequently, photovoltaic performance enhancement by 56% in efficiency and 80% in Jsc from its performance without compression and enhanced stability to a greater extent. A thin 20 nm Alumina had been used as an electron blocker to inhibit electron transfer into carbon and avoid recombination that enhanced the efficiency and charge collection (Jsc) by 30%, 64% respectively from its photovoltaic parameter without alumina. Moreover, CGn counter electrode-based PSCs extends stability remarkably in ambient atmospheric condition more than 7000 h.