The past few years have witnessed a rapid evolution of perovskite solar cells, an unprecedented photovoltaic (PV) technology with both relatively low cost and high power conversion efficiency. In this paper, we perform a life cycle assessment for two types of solution-processed perovskite solar modules to shed light on the environmental performance of this promising class of PVs. One module is equipped with FTO glass, a gold cathode, and mesoporous TiO2 scaffold; the other is equipped with ITO glass, a silver cathode, and ZnO thin film. We develop comprehensive life cycle inventories (LCIs) for all components used in the modules. Based on the LCI results, we conduct life cycle impact assessment for 16 common life cycle impact indicators, Eco-indicator 99, and two sustainable indicators: the energy payback time (EPBT) and the CO2 emission factor. We compare the results of Eco-indicator 99, the EPBT, and the CO2 emission factor among existing PV technologies, and further perform uncertainty analysis and sensitivity analysis for the two modules. The results demonstrate that perovskite solar modules possess the shortest EPBT, and future research should be directed to improving the system performance ratio and the device lifetime, and reducing precious metal consumption and energy-intensive operations in order to lower the CO2 emission factor.

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Perovskite photovoltaics: life-cycle assessment of energy and environmental impacts

The invention belongs to the field of fine chemicals and in particular relates to a method for preparing 9-fluorenone by liquid-phase oxidation. The method comprises the steps of dissolving fluorene in N, N-dimethyl formamide, and then adding a catalyst, stirring at 30-40 DEG C and under atmospheric pressure, carrying out air oxidation, reacting for 0.5-3 hours, distilling, filtering, washing with water and drying to obtain 9-fluorenone of which the yield is 98% and the purity is 99-99.5%, wherein the feed weight ratio of fluorene to N, N-dimethylformamide is 1 to (2-5), and the feed molar ratio of fluorene to potassium hydroxide is 1 to (0.01-0.05). The solvent used in the method disclosed by the invention can be recycled without further processing. The method disclosed by the invention has the advantages of mild reaction conditions, simple operation, relatively small amount of solvent, high yield, low cost, low environmental pollution and relatively short reaction time, the solvent needs not to be further processed and can be recycled after being used and the method is suitable for large-scale industrial production.

Method for preparing 2-bromofluorenone by liquid-phase oxidation

The invention relates to a method for separating fluorene and fluorenone by cooling crystallization and particle size classification. The method comprises the following steps: adding a mixture of thefluorene and the fluorenone into a solvent, performing stirring, performing heating to 40-50 DEG C for dissolution, after the solid is completely dissolved, performing cooling gradually to 20-35 DEG C, only adding a fluorenone seed crystal into the solution, continuing cooling to 0-10 DEG C, performing filtration on crystal slurry, performing drying to obtain a crystal mixture, after drying is performed, performing sieving on the crystal mixture by using a standard sieve with different meshes, and classifying the mixture into three levels according to particle size distribution results, wherein different particle size levels correspond to fluorine or fluorenone with different purity. The method provided by the invention can realize effective separation of low eutectic composition of the fluorene and the fluorenone, and obtain the fluorene and fluorenone crystal products with higher purity; and the method is simple and safe and has low costs.

Method for separating fluorene and fluorenone by cooling crystallization and particle size classification

The invention discloses a method for preparing coarse fluorene and fluorenone by taking wash oil as a raw material. The method comprises the following steps of: firstly, carrying out acid and alkali treatment on wash oil fraction obtained by fractionating coal tar, and enriching in a rectifying way to obtain coarse fluorene; secondly, converting fluorene in the coarse fluorene into fluorenone by an air liquid phase catalytic oxidation method; and based on ethylene glycol as entrainer, carrying out azeotropic distillation on reaction mixture to separate the fluorenone in the reaction mixture. The method has the advantages that a process route of first reaction and second separation is adopted, so that the fluorenone can be directly prepared by taking the coarse fluorene as the raw material, therefore, the fluorenone can be more easily separated from the reaction mixture; and the conventional preparation method of the fluorenone by firstly separating the fluorene from the coarse fluorene can be replaced, as the conventional method has the problems such as large material loss, high energy consumption, high cost, environment pollution and the like since the fluorene is very hard to separate.

Zhonglan Bai

Papers

Method for preparing coarse fluorene and fluorenone by taking wash oil as raw material