Nickel Oxide Monodispersed Quantum Dots as Hole Transport Layer in n-i-p Hybrid Perovskite Solar Cells

In this work NiO monodispersed quantum dots (QDs) were synthesized by the reduction of nickel (II) acetylacetonate with the borane-trimethylamine complex in a mixture of oleylamine, which acted as capping agent and helped to control the particle size growth. These were then used as a hole transport layer in regular (n-i-p) type organic-inorganic hybrid perovskite solar cells. Morphology of the NiO QDs was observed with Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HR-TEM) that revealed a monodispersed particles of an average particle size of about 5.5 +/- 0.5 nm with distinct lattice fringes (spacing of 0.24 nm). A solar cell was fabricated on FTO glass by coating compact TiO2, methylammonium lead halide (MAPbI), NiO-QDs and gold electrode (FTO/c-TiO2/MAPbI/NiO/Au). With the fabricated cell, we were able to obtain photo-conversion efficiency of 6.2%, fill factor of 0. 56, J(sc) is 10.77 mA/cm2 and V-oc is 1.02 V, which is a reasonable value for such cells.