We report direct experimental evidence for a layer-dependent step-edge barrier in organic thin film growth, investigating di-indenoperylene on SiO_{2} as an archetypical system. In particular, we show that a noticeable Ehrlich-Schwöbel effect emerges only beyond the 3rd molecular layer, accompanied by mass step-upward diffusion. We further disclose that this thickness dependence of the interlayer transport is directly related to molecular reorientations during the first stages of the growth. This is ultimately responsible for a morphological transition from layer-by-layer growth to surface rapid roughening. These experimental findings should compel further development of molecular-scale models for organic thin film growth.
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http://dx.doi.org/10.1103/PhysRevLett.103.136101 | DOI Listing |
Polymers (Basel)
January 2025
Department of Physics, Washington State University, Pullman, WA 99163, USA.
This work aims to determine the mechanism of the photomechanical response of poly(Methyl methacrylate) polymer doped with the photo-isomerizable dye Disperse Red 1 using the non-isomerizable dye Disperse Orange 11 as a control to isolate photoisomerization. Samples are free-standing thin films with thickness that is small compared with the optical skin depth to assure uniform illumination and photomechanical response throughout their volume, which differentiates these studies from most others. Polarization-dependent measurements of the photomechanical stress response are used to deconvolute the contributions of angular hole burning, molecular reorientation and photothermal heating.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Military Institute of Chemistry and Radiometry, gen A. Chruściela "Montera" 105, 00-910 Warsaw, Poland.
One of the main objectives of the ion mobility spectrometry (IMS) technique is to reduce moisture in detection systems, which causes the formation of ion clusters and ion water and a reduction in formed clusters' activity. Thus, one of the methods limiting moisture in a sampling injection system is to use hydrophobic polymeric membranes. The use of membranes with high permeability relative to the analysed organic compounds is required, including toxic agents in air (TAAs).
View Article and Find Full Text PDFMikrochim Acta
January 2025
Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, National & Local Joint Engineering Research Center for Mineral Salt Deep Utilization, Huaiyin Institute of Technology, Huaian, 223003, P. R. China.
A highly sensitive and selective electrochemical biosensor was developed for the detection of kanamycin using a core-hollow-shell structured peroxidase-mimic nanozyme, CHS-Fe₃O₄@@ZIF-8. The synthesized CHS-FeO@@ZIF-8 was characterized with scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the CHS-FeO@@ZIF-8 exhibits excellent peroxidase-like activity due to its ultra-thin hollow layer.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
This paper demonstrates the use of organic thin-film transistors (OTFTs) to drive active digital mini light-emitting diode (mini-LED) backlights, aiming to achieve exceptional display performance. Our findings reveal that OTFTs can effectively power mini-LED backlights, reaching brightness levels exceeding 100,000 nits. This approach not only enhances image quality but also improves energy efficiency.
View Article and Find Full Text PDFSmall
January 2025
Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, 2628 CN, The Netherlands.
Miniaturization of next-generation active neural implants requires novel micro-packaging solutions that can maintain their long-term coating performance in the body. This work presents two thin-film coatings and evaluates their biostability and in vivo performance over a 7-month animal study. To evaluate the coatings on representative surfaces, two silicon microchips with different surface microtopography are used.
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