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Laser-induced graphitized periodic surface structure formed on tetrahedral amorphous carbon films
摘要： Femtosecond laser-induced periodic surface structure (LIPSS), graphitization and swelling observed on ultra-hard, hydrogen-free tetrahedral amorphous carbon (ta-C) films are examined and compared with those on hydrogenated amorphous carbon (a-C:H) films, nitride films, and glassy carbon plates. The threshold fluence for LIPSS formation on ta-C is approximately twice as high as that for other specimens, and the LIPSS period Λ near the threshold is very fine at ca. 80 nm. Λ gradually increases with increasing fluence, and rapidly increases to ca. 600 nm at a high fluence. The ablation rate also increases rapidly at this fluence. In addition, ta-C and a-C:H are graphitized by irradiation and expand in volume. The surface layer of ta-C film changes to nanocrystalline graphite as the fluence increases and the crystallinity is improved; however, at higher fluence, the crystallinity deteriorates suddenly similar to that at low fluence. At high fluence, the rapid increase in Λ and the ablation rate, and the sudden deterioration in crystallinity are determined as common phenomena for these disordered carbons. LIPSS formation and swelling over a large area by scanned spot irradiation produces submicron height flat hills with conductivity and surface functionality on the insulating surface.
关键词： Graphitization,Swelling,Laser-induced periodic surface structure,Femtosecond-laser processing,Nanocrystalline graphite,Tetrahedral amorphous carbon
更新于2025-09-23 15:21:01
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Symmetry and Topology Code of Cluster Crystal Structure Self-Assembly for Metal Oxides: Cs11O3-mP56, Rb(Cs11O3)-oP30, Cs(Cs11O3)-oP60, Rb3(Rb4)(Cs11O3)-oP84, (Cs4)(Cs6)(Cs11O3)-hP24, Rb9O2-mP22, (Rb3)(Rb9O2)-hP28, and (Rb2O)3(Rb13)-cF176
摘要： Geometric and topologic analysis was carried out for metal oxides Cs11O3-mP56, Rb(Cs11O3)-oP30, Cs(Cs11O3)-oP60, Rb3(Rb4)(Cs11O3)-oP84, (Cs4)(Cs6)(Cs11O3)-hP24, Rb9O2-mP22, (Rb3)(Rb9O2)-hP28, and (Rb2O)3(Rb13)-cF176, which are formed from oxygen-containing metal melts. Special algorithms of partitioning structural graphs into cluster structures (the TOPOS program package) were used to identify the precursor clusters of crystal structures. The precursor clusters participating in crystal structure self-assembly were identified to be three-octahedral Cs11O3, two-octahedral Rb9O2, octahedral Cs6, tetrahedral Cs4 and Rb4, and icosahedral Rb13. The symmetry and topology code of crystal structure self-assembly from precursor clusters was reconstituted as: primary chain → microlayer → microframework. The Cs11O3 and Rb9O2 crystal structures were found to be self-assembled from three-octahedral clusters Cs11O3 and two-octahedral clusters Rb9O2, respectively. The Rb(Cs11O3) and Cs(Cs11O3) framework structures are assembled from clusters Cs11O3 and accommodate Rb and Cs atoms in their voids. The Rb3(Rb4)(Cs11O3) framework structure is assembled from clusters Cs11O3 and Rb4 and accommodates Rb atoms in its voids. The (Cs6)(Cs4)(Cs11O3) framework structure is self-assembled from clusters Cs11O3, Cs6, and Cs4. The Rb3(Rb9O2)-hP28 framework structure is assembled from clusters Rb9O2 and atoms Rb; the (Rb2O)3(Rb13) framework structure is assembled from icosahedra Rb13 and clusters Rb2O.
关键词： octahedral,and icosahedral precursor clusters,crystal structure self-assembly,and Rb metal oxides,Cs,tetrahedral,Rb-,Cs-
更新于2025-09-19 17:15:36
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Tetrahedral amorphous carbon prepared filter cathodic vacuum arc for hole transport layers in perovskite solar cells and quantum dots LEDs
摘要： In this study, we demonstrated the feasibility of using tetrahedral amorphous carbon (ta-C) films coated through the filtered cathodic vacuum arc (FCVA) process as a hole transport layer (HTL) for perovskite solar cells (PSCs) and quantum dots light-emitting diodes (QDLEDs). The p-type ta-C film has several remarkable features, including ease of fabrication without the need for thermal annealing or any other post-treatment, reasonable electrical conductivity, optical transmittance, good chemical stability, and a high work function. Therefore, we present a simple and effective method to improve the performance of PSCs and QDLEDs by applying ta-C films as a HTL. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy examinations show that the electrical properties (sp3/sp2 hybridized bond) and work function of the ta-C HTL are appropriate for PSCs and QDLEDs. In addition, in order to correlate the performance of the devices, the optical, surface morphological, and structural properties of the FCVA-grown ta-C films with different thicknesses (5 ~ 20 nm) deposited on the ITO anode are investigated in detail. The optimized ta-C film with a thickness of 5 nm deposited on the ITO anode had a sheet resistance 10.33 Ohm/square, a resistivity of 1.34 × 10-4 Ohm-cm, and an optical transmittance of 88.97%. Compared to the reference PSC with p-NiO HTL, the PSC with 5 nm thick ta-C HTL yielded a higher power conversion efficiency (PCE, 10.53%) due to its improved fill factor. Further, performance of QDLEDs with 5 nm thick ta-C hole injection layers (HIL) showed better than performance of QDLEDs with different ta-C thicknesses. It is concluded that FCVA grown ta-C films have the potential to serve as HTL and HIL in next-generation PSCs and QDLEDs.
关键词： Perovskite solar cells,Hole transport layer (HTL),Quantum dots LEDs,Tetrahedral amorphous carbon (ta-C) film,Hole injection layer (HIL)
更新于2025-09-12 10:27:22
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Encapsulation of Organic Dyes within an Electron-Deficient Redox Metal-Organic Tetrahedron for Photocatalytic Proton Reduction
摘要： The design of artificial systems that mimic highly evolved and finely tuned natural photosynthetic systems is a subject of intensive research. By incorporating electron-deficient anthraquinone within the ligand backbone, a redox-active Ni-based tetrahedron was developed as a redox vehicle for the construction of an artificial photosynthesis system. The tetrahedron can encapsulate fluorescein within its cavity for light-driven H2 evolution, with the turnover number reaching 1200 moles H2 per mole redox catalyst. This well-designed supramolecular system displayed a significantly superior activities compared with the reference mononuclear compound or introducing an inactive inhibitor (ATP), which confirmed this enzymatic photocatalytic behaviour.
关键词： light-driven H2 evolution,metal-organic tetrahedral,anthraquinone,supramolecular chemistry
更新于2025-09-10 09:29:36
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Ga-SBA-3 A novel nanostructured material: synthesis, characterization and application
摘要： This paper reports for the first time the incorporation of gallium into the structure of the mesoporous SBA-3 material in order to modify the intrinsic acidity of the material. The nanostructured material was characterized by ICP, XRD, NMR-MAS, XPS, FTIR, SEM, TEM and UV Vis., Pyridine was used as a probe molecule for the determination of its acidity following the amount and type of acidic sites by FTIR. In addition, aniline adsorption/desorption studies and subsequent in-situ polymerization, PANI/Ga-SBA-3, were carried out with the aim of producing a nanocomposite with conductive properties. The original material had good structural regularity and acidity of Br?nsted and Lewis; the study indicates the effective incorporation of Ga into a network in tetrahedral form, with most in the interior of the lodging and a low proportion on the external surface. Gallium was introduced via post synthesis using Ga-Nitrate in appropriate conditions. The PANI/Ga-SBA-3 composite also showed a conductivity of 2.5x10-3 S/cm, higher than that of its homologs Al-SBA-3 and Al-MCM- 41.
关键词： Ga in tetrahedral form,PANI/Ga-SBA-3,Post synthesis incorporation,Br?nsted and Lewis acidity,Ga-SBA-3,conductive nanocomposite
更新于2025-09-09 09:28:46
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Intrinsically Porous Dual-Responsive Polydiacetylenes Based on Tetrahedral Diacetylenes
摘要： The combinatorial functionalization in a single molecular framework by structural integration utilizing multiple functional materials to create prede?ned structural morphology and multistimuli-responsive smart materials has attracted intensive attention. Herein, we constructed intrinsically porous and dual-responsive supramolecule, TeDA, by introducing a photopolymerizable diacetylene template (10,12-pentacosadiynoic acid) to the sterically rigid tetrahedral tetraphenylmethane (TPM) core. The self-assembled monomeric TeDA is transformed into the covalently cross-linked blue-phase polydiacetylene (TePDA) by UV irradiation (UV 254 nm). The BET measurement and examination of SEM images con?rm the mesoporous characteristic for TeDA/PDA. Very interestingly, the blue-phase TePDA produces a naked-eye detectable colorimetric response to heat and VOCs (liquid and vapor phase). Most importantly, TePDA exhibits reversible thermochromism and excellent colorimetric response to chloroform vapors. To signify the structural in?uence of TPM on material properties, we also studied non-TPM derivatives. The TeDA/PDA integrated system demonstrates potential applications in developing multistimuli-responsive sensors.
关键词： dual-responsive,porous,thermochromism,VOCs detection,colorimetric response,polydiacetylenes,tetrahedral diacetylenes
更新于2025-09-04 15:30:14