Photovoltaic characteristics of organic-inorganic hybrid perovskite CH 3 NH 3 PbI 3 solar cells with NiO hole transport layer

Since it was firstly reported in 2009, organic-inorganic hybrid perovskite solar cells based on halide elements have been one of promising new-type solar cells in replacement of traditional silicon-based solar cells due to their simple fabrication technology and high power conversion efficiency (PCE). However, in order to guarantee high PCE, they usually need expensive organic hole/electron transport materials, which is not conducive to cost reduction. In this paper, we choose NiO, one of cheap and stable inorganic oxide materials, as the hole transport material. 40 nm -thick NiO film is firstly deposited on ITO-covered glasses by using spin-coating method, then 250 nm -thick CH3NH3PbI3 films with an average grain size of about 150 nm is deposited on it by using two-step solution method under optimized conditions. After covering it with a 50 nm -thick PCBM film and 150 nm -thick Ag top electrodes, an inverted-planar-structure of solar cell based on ITO/NiO/CH3NH3PbI3/PCBM/Ag is obtained. Surface morphology and crystal structure of NiO films annealed at different temperatures has been studied, as well as photovoltaic properties of solar cells fabricated. Comparative experimental results reveal that the 500°C-annealed NiO film is dense, and smooth with a relatively good crystallinity. Under simulated solar radiation in atmosphere condition, the unsealed solar cell with the 500°C-annealed NiO hole transport layer exhibits a PCE of ~7.63% and an open-circuit voltage V oc of > 1 V . This V oc value is higher than that of other organic-inorganic hybrid perovskite solar cells with NiO hole transport layer fabricated under similar condition.