A highly efficient design of a two-channel wavelength demultiplexer in the visible region is presented with finite-difference time-domain simulations. The design process is described in detail with particular attention to the challenges inherent in fabrication of an actual device. A 2D triangular lattice photonic crystal with 75nm air pores in a silicon nitride planar waveguide provides the confinement for visible light. The device losses due to fabrication errors such as stitching misalignment of write fields during e-beam lithography and variation in air pore diameters from etching are modeled using realistic parameters from initial fabrication runs. These simulation results will be used to guide our next generation design of high efficiency photonic crystal based demultiplexing devices.
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http://dx.doi.org/10.1364/oe.14.007931 | DOI Listing |
Nanoscale
January 2025
Physical Chemistry, TU Dresden, Zellescher Weg 19, 01069 Dresden, Germany.
Tunable optical properties exhibited by semiconductor nanocrystals (NCs) in the near infrared (NIR) spectral region are of particular interest in various applications, such as telecommunications, bioimaging, photodetection, photovoltaics, . While lead and mercury chalcogenide NCs do exhibit exemplary optical properties in the NIR, Cu-In-Se (CISe)-based NCs are a suitable environment-friendly alternative to these toxic materials. Several reports of NIR-emitting (quasi)spherical CISe NCs have been published, but their more complex-shaped counterparts remain rather less explored.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden.
One of the key advantages of perovskite light-emitting diodes (PeLEDs) is their potential to achieve high performance at much higher current densities compared to conventional solution-processed emitters. However, state-of-the-art PeLEDs have not yet reached this potential, often suffering from severe current-efficiency roll-off under intensive electrical excitations. Here, we demonstrate bright PeLEDs, with a peak radiance of 2409 W sr m and negligible current-efficiency roll-off, maintaining high external quantum efficiency over 20% even at current densities as high as 2270 mA cm.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China. Electronic address:
3D printing technology is one of the most promising strategies for constructing topological functional materials. The development of functional inks is a core issue in the technical development of 3D printing technology. In this study, we engineered photonic crystal inks based on chiral nematic liquid crystals of cellulose derivative, i.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Crystalline organic semiconductors, recognized for their highly ordered structures and high carrier mobility, have emerged as a focal point in the field of high-performance optoelectronic devices. Nevertheless, the intrinsic unipolar properties, characterized by imbalanced hole and electron transport capabilities, have continuously represented a significant challenge in the advancement of high-performance crystalline thin-film organic light-emitting diodes (C-OLEDs). Here, a bipolar solid-solution thin film with a maintained crystal structure has been fabricated using 2-(4-(9H-carbazol-9-yl)phenyl)-1(3,5-difluorophenyl)-1H-phenanthro [9,10-d]imidazole (2FPPICz) and 4-(1-(3,5-difluorophenyl)-1H-imidazo[4,5-][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline (2Fn) via a weak epitaxial growth (WEG) process, exhibiting nearly equivalent hole and electron mobilities (10-10 cm V s).
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK.
Most current highly efficient organic solar cells utilize small molecules like Y6 and its derivatives as electron acceptors in the photoactive layer. In this work, a small molecule acceptor, SC8-IT4F, is developed through outer side chain engineering on the terminal thiophene of a conjugated 6,12-dihydro-dithienoindeno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IDTT) central core. Compared to the reference molecule C8-IT4F, which lacks outer side chains, SC8-IT4F displays notable differences in molecule geometry (as shown by simulations), thermal behavior, single-crystal packing, and film morphology.
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