Newly Developed Broadband Antireflective Nanostructures by Coating a Low-Index MgF2 Film onto a SiO2 Moth-Eye Nanopattern.

A newly developed nanopatterned broadband antireflective (AR) coating was fabricated on the front side of a glass/indium tin oxide/perovskite solar cell (PSC) by depositing a single interference layer onto a two-dimensional (2D)-patterned moth-eye-like nanostructure. The optimized developed AR nanostructure was simulated in a finite-difference time domain analysis. To realize the simulated developed AR nanostructure, we controlled the SiO2 moth-eye structure with various diameters and heights and a MgF2 single layer with varying thicknesses by sequentially performing nanosphere lithography, reactive ion etching, and electron-beam evaporation. Optimization of the developed AR nanostructure, which has a 100 nm-thick MgF2 film coated onto the SiO2 moth-eye-like nanostructure (diameter 165 nm and height 400 nm), minimizes the reflection loss throughout the visible range. As a result, the short-circuit current density (JSC) of the newly AR-coated PSC increases by 11.80%, while the open-circuit voltage (VOC) remains nearly constant. Therefore, the power conversion efficiency of the newly developed AR-decorated PSC increases by 12.50%, from 18.21% for a control sample to 20.48% for the optimum AR-coated sample. These results indicate that the newly developed MgF2/SiO2 AR nanostructure can provide an advanced platform technology that reduces the Fresnel loss and therefore increases the possibility of the commercialization of glass-based PSCs.

Safety of Donation From Brain-dead Organ Donors With Central Nervous System Tumors: Analysis of Transplantation Outcomes in Korea.

BACKGROUND: This study aims to verify the condition of recipients of solid organs from donors with central nervous system (CNS) tumors and determine the risk of disease transmission due to transplantation. METHODS: Twenty-eight brain-dead organ donors with CNS tumors and 91 recipients who received solid organs from January 1, 2005, to December 31, 2014 in Korea were investigated using the Korean Network of Organ Sharing data. RESULTS: Of the 36 recipients of organs from the 11 donors whose pathological results were not verified, 4 developed the following tumors: renal cell carcinoma, carcinoma in situ of the cervix uteri, B-cell lymphoma, and colon cancer. Among 51 recipients from 17 donors with CNS tumor, no recipient had the same tumor as the donors. Six were classified as high-risk donors according to the World Health Organization classification, and 14 recipients from these donors did not develop tumor after transplantation. The remaining 11 donors were classified as low-risk donors according to the World Health Organization classification but as high-risk donors according to the Malignancy Subcommittee of the Disease Transmission Advisory Committee of the Organ Procurement and Transplantation Network/United Network for Organ Sharing. Of the 37 recipients, 3 had recurring hepatocellular carcinoma with lung and bone metastases, thyroid cancer, and Kaposi's sarcoma after transplantation. CONCLUSIONS: The risk of disease transmission due to organ transplantation from donors with CNS tumors was very low. Thus, organ donation from such donors should be promoted actively to expand the donor range.

Enhanced Surface Properties of Light-Trapping Si Nanowires Using Synergetic Effects of Metal-Assisted and Anisotropic Chemical Etchings.

Metal-assisted chemical etching (MACE) has been widely explored for developing silicon (Si)-based energy and optical devices with its benefits for low-cost and large-area fabrication of Si nanostructures of high aspect ratios. Surface structures and properties of Si nanostructures fabricated through MACE are significantly affected by experimental and environmental conditions of etchings. Herein, we showed that surfaces and interfacial energy states of fabricated Si nanowires can be critically affected by oxidants of MACE etching solutions. Surfaces of fabricated Si nanowires are porous and their tips are fully covered with lots of Si nano-sized grains. Strongly increased photoluminescence (PL) intensities, compared to that of the crystalline Si substrate, are observed for MACE-fabricated Si nanowires due to interfacial energy states of Si and SiOx of Si nano-sized grains. These Si grains can be completely removed from the nanowires by an additional etching process of the anisotropic chemical etching (ACE) of Si to taper the nanowires and enhance light trapping of the nanowires. Compared with the MACE-fabricated Si nanowires, ACE-fabricated tapered Si nanowires have similar Raman and PL spectra to those of the crystalline Si substrate, indicating the successful removal of Si grains from the nanowire surfaces by the ACE process.