我国国有经济转制效率分析

文章对国有经济三种转制方式和形态的效率进行了分析比较,指出了双生变量转制方式和资本与实物混合转制形态,应是我们的战略选择。

科研院所产权改革与改制成效的实证研究——以湖南为例

近年来,我国科研院所转制工作取得很大成效,产权改革稳步推进。基于主成分分析法的实证研究发现,科研院所的产权改革状况对转制效率产生显著影响,不同院所在综合水平、经营能力和创新能力出现了较为明显的分化。因此,科研院所产权改革意义重大,提高要从加快产权改革步伐、创新资产管理模式、健全改革配套政策、建立现代企业制度等方面着力推进。

Reveal the growth mechanism in perovskite films via weakly coordinating solvent annealing

In this study, we investigated the nucleation mechanism of perovskite films by employing isopropanol(IPA), a weakly coordinating solvent, to anneal both PbI2 and CH3 NH3 PbI3 in the sequential deposition and CsPbI3 in the one-step deposition. IPA solvent annealing(IPA SA) of PbI2 films was carried out at different temperatures. The grain size,compactness, roughness and morphology of PbI2 and CH3 NH3 PbI3 films were seriously affected by annealing methods. Similarly, weakly coordinating solvent annealing process was also employed to anneal all inorganic CsPbI3 perovskite in a one-step method. A continuous and dense CsPbI3 film with uniform grain size was obtained. We recognized that weakly coordinating solvent annealing for perovskite could regulate the dissolution-recrystallization process via controlling the volume of residual solvent in perovskite intermediate films. The power conversion efficiency(PCE) of conventional CH3 NH3 PbI3 perovskite solar cells(PSCs)reached 17.4% and that of CsPbI3 PSCs reached 2.5% based on this sequential IPA SA process.

Performance improvement of organic bulk heterojunction solar cells by using dihydroxybenzene as additive

We report the enhanced performance of organic solar cells(OSCs) based on regioregular poly(3-hexylthiophene)(P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester(PCBM) blend by using dihydroxybenzene as additive in the active layer.The effect of the content of the additives on electrical characteristics of the device is studied.The device with 0.2 wt% dihydroxybenzene additive achieves the best power conversion efficiency(PCE) of 4.58% with Jsc of 12.5 mA/cm2,Voc of 0.65 V,and FF of 66.6% under simulated solar illumination of AM 1.5G(100 mW/cm2),compared with the control device with PCE of 3.39%(35% improvement compared with the control device).The XRD measurement reveals that the addition of additives induces the crystallization of P3HT and establishes good inter-network to increase the contact area of donor and acceptor,and then helps charge to be effectively transferred to the electrode to reduce the chance of recombination.All evidences indicate that the dihydroxybenzene is likely to be a promising new type additive that can enhance the performance of organic bulk heterojunction solar cells.

Composite electrolytes based on poly(ethylene oxide) and binary ionic liquids for dye-sensitized solar cells

The sunlight is the largest single available source of clean and renewable energy to ensure human society＇s sustainable devel- opment. Owing to their low production cost and high energy conversion efficiency, dye-sensitized solar cells （DSSCs） have been regarded as good alternatives to conventional photovoltaic devices. Herein, a series of composite electrolytes based on poly（ethylene oxide） （PEO） and the binary ionic liquids 1-propyl-3-methy-imidazolium iodide （[PMIm]I） and l-ethyl-3- methylimidazolium thiocyanate （[EMIm][SCN]） were prepared and then applied to fabricate six DSSCs. The composite elec- trolytes were characterized by fourier transform infrared spectroscopy （FTIS）, X-ray diffraction （XRD）, and electrochemical impedance spectra （EIS）. It was shown that the addition of binary ionic liquids would reduce the degree of crystallinity of PEO thus improving the ionic conductivities of the electrolytes by about 2 orders of magnitude. Investigation on the photovoltaic performances of these DSSCs showed that the fill factor （FF） could reach up to 0.67 and energy conversion efficiency （η） could reach up to 4.04% under AM 1.5 full sunlight （100 mW/cm^2）.

Facile preparation of organometallic perovskite films and high-efficiency solar cells using solid-state chemistry

The power conversion efficiency of organometallic perovskite-based solar cells has skyrocketed in recent years. Intensive efforts have been made to prepare high-quality perovskite films tailored to various device configurations. Planar heterojunction devices have achieved record efficiencies; however, the preparation of perovskite films for planar junction devices requires the use of expensive vacuum facilities and/or the fine control of experimental conditions. Here, we demonstrate a facile preparation of perovskite films using solid-state chemistry. Solid-state precursor thin films of CHBNH3I and PbI2 are brought into contact with each other and allowed to react via thermally accelerated diffusion. The resulting perovskite film displays good optical absorption and a smooth morphology. Solar cells based on these films show an average efficiency of 8.7% and a maximum efficiency of 10%. The solid-state synthesis of organometallic perovskite can also be carried out on flexible plastic substrates. Using this method on a PET/ITO substrate produces devices with an efficiency of 3.2%. Unlike existing synthetic methods for organometallic perovskite films, the solid-state reaction method does not require the use of orthogonal solvents or careful adjustment of reaction conditions, and thus shows good potential for mass production in the future.

Control of organic–inorganic halide perovskites in solid-state solar cells: a perspective

Since the year of 2009 when the first appli- cation of organohalide lead perovskite as the light har- vester in solar cells was reported, tremendous attention has been devoted to these new types of perovskite-based solid-state solar cells and remarkable power conversion efficiency of over 20 % has been achieved to date. In this review, we first introduce the properties of organic- inorganic halide perovskites and then focus on the notable achievements made on the perovskite layer to improve the power conversion efficiency of solid-state perovskite solar cells, which is featured by process engineering of the state-of-the-art lead methylammoni- um triiodide perovskite and material control of lead triiodide perovskites and other newly emerged per- ovskites. In the end, we wish to provide an outlook of the future development in solid-state perovskite solar cells. Provided that the instability and toxicity of solid- state perovskite solar cells can be solved, we will wit- ness a new era for cost-effective and efficient solar cells.

Carbon-free Cu_2ZnSn(S,Se)_4 film prepared via a non-hydrazine route

The kesterite Cu2ZnSn(S,Se)4(CZTSSe) is an ideal candidate for light harvesting materials in earth-abundant low-cost thinfilm solar cells(TFSC). Although the solution-based processing is a most promising approach to achieve low-cost solar cells with high power conversion efficiency, the issues of poor crystallinity and carbon residue in CZTSSe thin films are still challenging. Herein, a non-hydrazine solution-based method was reported to fabricate highly crystallized and carbon-free kesterite CZTSSe thin films. Interestingly, it was found that the synthetic atmosphere of metal organic precursors have a dramatic impact on the morphology and crystallinity of CZTSSe films. By optimizing the processing parameters, we were able to obtain a kesterite CZTSSe film composed of compact large crystal grains with trace carbon residues. Also, a viable reactive ion etching(RIE) processing with optimized etching conditions was then developed to successfully eliminate trace carbon residues on the surface of the CZTSSe film.

A low-temperature solution-processed copper antimony iodide rudorffite for solar cells

A copper antimony iodide rudorffite,Cu3SbI6, was first prepared by using a low-temperature solution-pro- cessing approach.Its film absorbs 320-520nm fight and has an indirect bandgap of 2.43eV.Solar cells with a structure of ITO/PEDOT:PSS/CusSbIJPC6~BM/AI were made,giving a power conversion efficiency of 0.50%and a fill factor of 67.09%.