H2 O-Etchant-Promoted Synthesis of High-Quality Graphene on Glass and Its Application in See-Through Thermochromic Displays.

Direct growth of graphene on glass can bring an innovative revolution by coupling the complementary properties of traditional glass and modern graphene (such as transparency and conductivity), offering brand new daily-life related applications. However, preparation of high-quality graphene on nonmetallic glass is still challenging. Herein, the direct route of low sheet resistance graphene on glass is reported by using in situ-introduced water as a mild etchant and methane as a carbon precursor via chemical vapor deposition. The derived graphene features with large domain sizes and few amorphous carbon impurities. Intriguingly, the sheet resistance of graphene on glass is dramatically lowered down to ≈1170 Ω sq-1 at the optical transmittance ≈93%, ≈20% of that derived without the water etchant. Based on the highly conductive and optical transparent graphene on glass, a see-through thermochromic display is thus fabricated with transparent graphene glass as a heater. This work can motivate further investigations of the direct synthesis of high-quality graphene on functional glass and its versatile applications in transparent electronic devices or displays.

Adhesion-Enhanced Vertically Oriented Graphene on Titanium-Covered Quartz Glass toward High-Stability Light-Dimming-Related Applications.

Improving the adhesion property of graphene directly grown on an insulating substrate is essential for promoting the reliability and durability of the related applications. However, effective approaches have rarely been reported, especially for vertically oriented graphene (VG) films grown on insulating templates. To tackle this, we have developed a facile synthetic strategy by introducing an ultrathin (10 nm-thick) titanium (Ti) film on a quartz glass substrate as the adhesion layer, for plasma-enhanced chemical vapor deposition (PECVD) growth of VG films. This synthetic process induces the formation of Ti, oxygen (O), carbon (C)-containing adhesion layer (Ti (O, C)), offering improved interfacial adhesion due to the formation of chemical bonds among Ti and C atoms. Dramatically improved surface and interface stabilities have been achieved, with regard to its counterpart without a Ti adhesion layer. Moreover, we have also realized precise controls of the transparent/conductive property, surface roughness, and hydrophobicity, etc., by varying the VG film growth time. We have also demonstrated the very intriguing application potentials of the hybrids in light-dimming related fields, that is, electro-heating defogging lenses and neutral density filters toward medical endoscope defogging and camera photography.

Ethanol-Precursor-Mediated Growth and Thermochromic Applications of Highly Conductive Vertically Oriented Graphene on Soda-Lime Glass.

Direct growth of vertically oriented graphene (VG) nanowalls on soda-lime glass has practical significance in extending the application of graphene to daily-life-related areas, such as gas sensors and conductive electrodes, via combining their complementary properties and applications. However, VG films derived by low-temperature deposition (e.g., on glass) usually present relatively low conductivity and optical transparency. To tackle this issue, an ethanol-precursor-based, radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) route for the synthesis of VG nanowalls is developed in this research, at around the softening temperature of soda-lime glass (∼600 °C) templates. The average sheet resistance, i.e., ∼2.4 kΩ·sq-1 (at transmittance ∼81.6%), is only one-half of that achieved by a traditional methane-precursor-based PECVD route. Based on the highly conductive and optically transparent VG/glass, as well as its scalable size up to 25 in. scale, high-performance reversible thermochromic devices were successfully constructed using VG/glass as transparent heaters. Hereby, this work should propel the scalable synthesis and applications of highly conductive VG films on glass in next-generation transparent electronics and switchable windows.

Blue Laser Projection Printing of Conductive Complex 2D and 3D Metallic Structures from Photosensitive Precursors.

Photosensitive precursors are developed for the printing of 2D and 3D conductive structures via blue laser projection printing. With the assistance of a photosensitizer, metal nanoparticles can be efficiently photosynthesized under laser irradiation of low light intensity (45-290 mW cm-2). By projecting well-defined laser patterns on the precursor, corresponding 2D metal structures with the finest line of about 50 µm can be formed on various substrates including flexible polymer thin films, curved substrates, and ground glass. Moreover, complex 3D objects with nanoparticles embedded in the polymeric matrix are constructed via 3D printing combining photoreduction of the metal precursor and photopolymerization of resin. The as-prepared structures exhibit promising conductivities after sintering (in the order of magnitude of 106 S m-1). A possible mechanism of photochemical synthesis of metal nanoparticles upon exposure to blue laser is proposed. The high efficiency and low cost of the technique, the complexity of the structures prepared, and the applicability to various substrates and metals (including silver, gold, and palladium) promise practical applications of this approach in the printed electronics industry.

Transparent Electrothermal Heaters Based on Vertically-Oriented Graphene Glass Hybrid Materials.

Transparent heating devices are widely used in daily life-related applications that can be achieved by various heating materials with suitable resistances. Herein, high-performance vertically-oriented graphene (VG) films are directly grown on soda-lime glass by a radio-frequency (rf) plasma-enhanced chemical vapor deposition (PECVD) method, giving reasonable resistances for electrothermal heating. The optical and electrical properties of VG films are found to be tunable by optimizing the growth parameters such as growth time, carrier gas flow, etc. The electrothermal performances of the derived materials with different resistances are thus studied systematically. Specifically, the VG film on glass with a transmittance of ~73% at 550 nm and a sheet resistance of ~3.9 KΩ/□ is fabricated into a heating device, presenting a saturated temperature up to 55 °C by applying 80 V for 3 min. The VG film on the glass at a transmittance of ~43% and a sheet resistance of 0.76 KΩ/□ exhibits a highly steady temperature increase up to ~108 °C with a maximum heating rate of ~2.6 °C/s under a voltage of 60 V. Briefly, the tunable sheet resistance, good adhesion of VG to the growth substrate, relative high heating efficiency, and large heating temperature range make VG films on glass decent candidates for electrothermal related applications in defrosting and defogging devices.

[Dual chamber pacing for vasovagal syncope].

OBJECTIVE: To investigate the effect of DDD pacing on vasovagal syncope (VVS). METHODS: Eleven patients diagnosed VVS (7 with heart inhibiton type, 4 with combination type)by tilt table test (TTT) in Shanghai Chest Hospital were selected into the study. They all were implanted DDD pacemaker in whom 9 with rate-drop response (RDR) function. All of them were prescribed beta-receptor blocker. The patients were followed-up at 1, 3, 6, 12, 24 months after being discharged. RESULTS: All the 11 patients with pacemaker implantation were free from syncope, in whom 4 still had pre-syncope discomfort, but the symptoms were slightly. Six patients took TTT again after pacemaker implantation. It was observed that pacing at an elevated rate started immediately when heart rate dropping to the lower threshold, and as a result syncope were prevented. CONCLUSION: In the VVS patients with recurrent syncope and severe heart inhibition, DDD pacing with RDR function could prevent from syncope efficiently.

[Advances in cucurbituril bonded stationary phases for chromatographic separation].

Cucurbit [n] urils (CB [n]), a kind of host molecules of the fourth generation supramolecule followed crown ethers, cyclodextrins and calixarenes in supramolecular chemistry, are macrocyclic ligands and consist of several glycoluril units. Their special molecular recognition based on unique separation selectivity and stability have gained great interest in supramolecular chemistry and chromatography. Hereby, we give a review of research progresses of cucurbit [n] urils structural features, its homologues and derivatives and their applications in chromatographic stationary phase.