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Highly transparent and crystallized nickel oxide thin film through magnetron sputtering is incorporated in CH3NH3PbI3 planar heterojunction perovskite solar cells (PSCs). In this work, the influence of substrate temperature on NiO film during magnetron sputtering and corresponding performance of PSCs were investigated. NiO thin films were prepared with different substrate temperatures, i.e., 20 °C, 150 °C, and 300 °C, named as 20-NiO, 150-NiO, and 300-NiO, separately. It is found that higher substrate temperature leads to better crystallinity of NiO film, and corresponding a higher PSCs efficiency. PSCs based on 300-NiO thin films’ inorganic hole transport layer show the best efficiency (up to 14.11%), which is about 32% higher than that of device based on 20-NiO. This is mainly due to the fact of 300-NiO thin films with the better light transmittance and higher hole mobility, promoting light absorption and photo-generated charge separation efficiency of perovskite layer, which leads to an improvement in device performance.

Growth of epitaxial graphene (EG) on silicon carbide (SiC) is regarded as one of the most effective routes to high-quality graphene towards practical applicability. We try to build up a model to illuminate the nucleation process of EG on SiC by thermal decomposition. The model is derived from some experimental results and discloses that surface diffusion plays an important role in the nucleation. For the chemical vapor deposition process used, the organic gas as carbon precursor enables carbon deposition quickly for supporting the growth of high-quality graphene via vapor transformation, so that the nucleated and final graphene becomes almost stress-free and mimics the free-standing graphene. Our findings have a potential in preparing high-quality graphene by controlling the nucleation conditions.