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.