In this article, we present a new paradigm for organometallic hybrid perovskite solar cell using NiO inorganic metal oxide nanocrystalline as p-type electrode material and realized the first mesoscopic NiO/perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM) heterojunction photovoltaic device. The photo-induced transient absorption spectroscopy results verified that the architecture is an effective p-type sensitized junction, which is the first inorganic p-type, metal oxide contact material for perovskite-based solar cell. Power conversion efficiency of 9.51% was achieved under AM 1.5 G illumination, which significantly surpassed the reported conventional p-type dye-sensitized solar cells. The replacement of the organic hole transport materials by a p-type metal oxide has the advantages to provide robust device architecture for further development of all-inorganic perovskite-based thin-film solar cells and tandem photovoltaics.

We report here a series of nontoxic and stable bismuth-based perovskite nanocrystals (PeNCs) with applications for photocatalytic reduction of carbon dioxide to methane and carbon monoxide. Three bismuth-based PeNCs of general chemical formulas A 3 Bi 2 I 9 , in which cation A + = Rb + or Cs + or CH 3 NH 3 + (MA + ), were synthesized with a novel ultrasonication top-down method. PeNC of Cs 3 Bi 2 I 9 had the best photocatalytic activity for the reduction of CO 2 at the gas−solid interface with formation yields 14.9 μmol g −1 of methane and 77.6 μmol g −1 of CO, representing a much more effective catalyst than TiO 2 (P25) under the same experimental conditions. The products of the photocatalytic reactions were analyzed using a gas chromatograph coupled with a mass spectrometer. According to electron paramagnetic resonance and diffuse-reflectance infrared spectra, we propose a reaction mechanism for photoreduction of CO 2 via Bi-based PeNC photocatalysts to form CO, CH 4 , and other possible side products.

A potential energy surface for the reaction of vinyl radical with molecular oxygen has been studied using the ab initio G2M(RCC,MP2) method. The most favorable reaction pathway leading to the major CHO + CH2O products is the following:  C2H3 + O2 → vinylperoxy radical 1 or 1‘ → TS 8 → dioxiranylmethyl radical 3 → TS 9‘ oxiranyloxy radical 10 → TS 11 → formyloxymethyl radical 12‘ → TS 13‘ → CHO + CH2O, where the rate-determining step is oxygen migration to the CC bridging position via TS 9‘, lying below the reactants by 14.3 kcal/mol. The C2H3O + O products can be formed by elimination of the oxygen atom from C2H3OO via TS 23, which is by 7.8 kcal/mol lower in energy than the reactants, but by 6.5 kcal/mol higher than TS 9‘. The hydrogen migration in 1‘ gives rise to another significant product channel:  C2H3 + O2 → 1‘ → TS 25‘ → C2H2 + O2H, with TS 25‘ lying below C2H3 + O2 by 3.5 kcal/mol. Multichannel RRKM calculations have been carried out for the total and individual rate constants for various channels using the G2M(RCC,MP2) energetics and molecular parameters of the intermediates and transition states. The computed low pressure reaction rate constant is in quantitative agreement with experiment. At atmospheric pressure, the title reaction is dominated by the stabilization of vinylperoxy radical C2H3OO at room temperature. In the 500−900 K temperature range, the CHO + CH2O channel has the highest rate constant, and at T ≥ 900 K, C2H3O + O are the major products. At very high temperatures, the channel producing C2H2 + O2H becomes competitive.