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GaN-based ultraviolet (UV) LEDs are widely used in numerous applications, including white light pump sources and high-density optical data storage. However, one notorious issue is low hole injection rate in p-type transport layer due to poorly activated holes and spontaneous polarization, giving rise to insufficient light emission efficiency. Therefore, improving hole injection rate is a key step towards high performance UV-LEDs. Here, we report a new method of suppressing spontaneous polarization in p-type region to augment light output of UV-LEDs. This was achieved by simply passivating graphene oxide (GO) on top of the fully fabricated LED. The dipole layer formed by the passivated GO enhanced hole injection rate by suppressing spontaneous polarization in p-type region. The homogeneity of electroluminescence intensity in active layers was improved due to band filling effect. As a consequence, the light output was enhanced by 60% in linear current region. Our simple approach of suppressing spontaneous polarization of p-GaN using GO passivation disrupts the current state of the art technology and will be useful for high-efficiency UV-LED technology.
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http://dx.doi.org/10.1038/srep07778 | DOI Listing |
BME Front
September 2025
State Key Laboratory of High Performance Ceramics, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
This work aims to construct a functional titanium surface with spontaneous electrical stimulation for immune osteogenesis and antibacteria. A silver-calcium micro-galvanic cell was engineered on the titanium implant surface to spontaneously generate microcurrents for osteoimmunomodulation and bacteria killing, which provides a promising strategy for the design of a multifunctional electroactive titanium implant. Titanium-based implants are usually bioinert, which often leads to inflammation-induced loosening.
View Article and Find Full Text PDFAdv Mater
September 2025
Soft Matter Optics Group, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw, 50-370, Poland.
Nematic Liquid Crystals (LCs), noted for their simple molecular alignment and broad use in optoelectronics, remain unmodified for over a century. However, in 2017, a unique polar phase, the ferroelectric nematic (N), is confirmed. Subsequently, in 2024, the revolutionary spontaneous mirror symmetry breaking of ferroelectric twist-bend nematic chiral structures (N phase) is demonstrated.
View Article and Find Full Text PDFACS Nano
September 2025
Departments of Biomedical Engineering and Chemical Engineering, University of California, Davis, California 95616, United States.
Bolaamphiphiles─amphiphilic molecules with polar groups at each of the two ends of a hydrophobic tail with pH-sensitive spontaneous molecular curvatures, endow membranes of extremophiles with an exquisite balance between stability (or robustness) and adaptability (or plasticity). But how the presence (or real-time insertion) of bolaamphiphiles influences lamellar lipid membranes is poorly understood. Using a combination of time-resolved confocal fluorescence microscopy, in situ small-angle X-ray and neutron scattering (SAXS and SANS), and neutron spin echo (NSE) measurements, we monitor here the pH-dependent interactions of nanoscopic vesicles of a representative bolaamphiphile─a glucolipid consisting of a single glucose headgroup and a C18:1 (oleyl) fatty acid tail (G-C18:1)─with the membranes of an essentially cylindrical fluid-phase phospholipid (dioleoylphosphatidylcholine, DOPC).
View Article and Find Full Text PDFbioRxiv
August 2025
Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
Mammalian female meiosis is uniquely regulated to produce a developmentally competent egg capable of supporting embryogenesis. During meiosis I, homologous chromosomes segregate, with half extruded into the first polar body. The egg then arrests at metaphase II and only resumes meiosis and extrudes the second polar body following fertilization.
View Article and Find Full Text PDFACS Nano
September 2025
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
A combination of experiments and optical modeling provided insight into the mechanism of mesoscale woodpile formation in response to an orthogonal shift in polarization during photoelectrochemical deposition of Se-Te. Cathodic deposition of semiconducting Se-Te using spatially uniform, linearly polarized illumination produced arrays of lamellae that were aligned parallel to the optical E-field oscillation. Continued deposition in conjunction with an orthogonal shift in the polarization direction then produced aligned bridging features that spanned the void space between, and were orthogonal to, the preexisting lamellae.
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