Comb-shaped Sb₂S₃ nanorod arrays on ZnO nanofibers for thin-film photovoltaics

A hierarchical composite of Sb₂S₃ nanorods grown on zinc oxide (ZnO) nanofiber was prepared, and the formation of comb-shaped Sb₂S₃ nanorod arrays on the ZnO nanofibers was confirmed. It was found that the size of the diameter and the density of the nanorods are regulatable by changing the concentration of polyvinyl pyrrolidone as an additive for the growth of Sb₂S₃ nanorod on ZnO nanofiber. The obtained Sb₂S₃ nanorod arrays were applied as a light absorber for thin-film solar cells composed of glass-fluorine-doped tin oxide/compact ZnO/ZnO nanofibers−ZnS/Sb₂S₃ nanorod arrays/poly(3-hexylthiophene-2, 5-diyl)/MoOx/Ag. The rectification ratio and photocurrent generation efficiency of the comb-shaped Sb₂S₃ nanorod arrays were improved as compared with the heterojunction of randomly stacked Sb₂S₃ nanorods. Smaller series resistance (Rs) of 8.13 Ω cm⁻² and an ideality factor (n) of 2.84 with the comb-shaped Sb₂S₃ nanorod arrays than those of the randomly stacked ones of Rs = 15.01 Ω cm⁻² and n = 3.83 also indicated superior charge extraction property and suppressed recombination of the comb-shaped Sb₂S₃ nanorod arrays at the interface

Solubilization of sulfuric acid lignin by ball mill treatment with excess amounts of organic compounds

In order to improve the solubility of sulfuric acid lignin (SL) in N, N-dimethylformamide (DMF), dry ball milling with excess amounts of additives such as L-tartaric acid was performed. Although the ball-milled SL without any additives was not soluble in DMF, when the SL was ball milled with an excessive amount of L-tartaric acid (the concentration of SL to be 0.1%), the dispersion and solubility of SL in DMF detected by the dynamic light scattering was greatly improved. Furthermore, the DMF solution showed clear photoluminescence, indicating that the distance between luminophores was modulated due to dispersion on the nanoscale. The structural analysis of the isolated lignin showed a decrease in molecular weight and the introduction of carboxylic acid groups. In other words, the introduction of hydrophilic functional groups into the lignin and simultaneously decrease in the molecular weight due to the cleavage of lignin linkages is considered to result in good dispersion in DMF on both the micro and macro scales. Similar effects were observed with the other chemicals containing several hydrophilic groups such as citric acid, D-glucose, and polyacrylic acid. Furthermore, this method is applicable to various lignins other than SL, and it is expected to utilize unused lignin resources

Luminescence-based circular polarization convertors: polarization conversion of linearly polarized photoluminescence from one-dimensionally aligned quantum rods using retardation films

発光式円偏光コンバータの開発に成功 --円偏光純度と明るさを両立させる新たな円偏光生成技術として期待--. 京都大学プレスリリース. 2023-01-24.Existing methods for generating circularly polarized (CP) light from an unpolarized light source without using external electrical energy have drawbacks, such as a trade-off relationship between CP light intensity and purity. Here, we demonstrate an approach for the generation of high-purity, high-intensity CP light based on a luminescence-based CP convertor composed of a linearly polarized luminescence (LPL) film and a quarter-wave plate. The LPL films, fabricated by one-dimensional alignment of semiconductor quantum rods and laminated with a quarter-wave plate, enabled effective conversion of LPL to high-purity CP light and retained the photoluminescent spectral pattern, light intensity, and the large degree of polarization. The sign of CP light was easily switched by changing the orientation of the quarter-wave plate and the LPL polarization plane. Furthermore, we also demonstrate the first example of parallel-type and multi-layered luminescence-based CP light convertors for multiplexing optical information. Our findings will aid the design of next-generation CP light-generating materials

Electron-Acceptor Nanomaterials Fabricated by Electrospinning for Polymer Solar Cells

10th Eco-Energy and Materials Science and Engineering Symposium, EMSES 2012 ; 5 December 2012 through 8 December 2012 ; Muang, Ubon-RatchathaniNanofibers of a fullerene derivative (phenyl-C61-butyric acid methyl ester, PCBM) and a conventional polymer (polyvinylpyrrolidone, PVP) composite were prepared by electrospinning of blended solutions in the mixed solvent of chlorobenzene and methanol. At a fixed concentration of PVP, the average diameter of fibers was found to decrease with increasing composition of PCBM, because of the increase of conductivity of spinning solutions. The increase in PCBM composition resulted in a relative blue shift in UV-vis absorption peak. PVP was easily removed from PCBM/PVP fibers by Soxhlet extraction. After the removal of PVP, pure PCBM were obtained as nanorods connected in fiber direction. The preliminary utilization of the PCBM nanostructure as an electron-acceptor material in polymer solar cells was investigated

The Pathogenesis of Tuberculous Meningitis. A Criticism of Rich's Focus-theory

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。1) The pathogenesis of tuberculous meningitis was studied by the preparation of the spreading specimens of meninges. 2) The tuberculous meningitis in infant succeeded to primary tuberculosis will break out by the cerebrospinal fluid infection from multiple caseous foci in meninges, which were formed in the walls of meningeal arteriols in the early dissemination. 3) Sometimes caseous foci in brains and choroid plexuses were found, but these foci are not essential as the cause of meningitis. 4) There will be rarely some cases, in which bacilli will be discharged in the subarachnoid space from the caseous foci in brains. In such cases tuberculous meningitis apt to be chronic and to relapse in spite of the adequate therapy

Quantum dot-modified titanium dioxide nanoparticles as an energy-band tunable electron-transporting layer for open air-fabricated planar perovskite solar cells

Perovskite solar cells have been attracted as new representatives for the third-generation photovoltaic devices. Simple strategies for high efficiency with the long-term stability of solar cells are the challenges for commercial solar cell technology. Another challenge of the development toward industrial scale in perovskite solar cells is the production under the ambient and high humidity. In this sense, we successfully fabricated perovskite solar cells via solution depositions of all layers under ambient air with a relative humidity above 50%. Titanium dioxide (TiO₂) nanoparticles with the roles for efficient charge extraction and electron transportation properties were used as an electron-transporting layer in the cell fabrication. The modification of TiO₂ nanoparticles for energy band adjustment was done by doping with nontoxic cadmium sulfide (CdS) quantum dots. With the variation of CdS concentrations, energy band is not only changeable, but the enhancement of the perovskite solar cells efficiency could be achieved compared with the conventional cells made of pristine-TiO₂ film and TiO₂ nanoparticles