Highly Conductive Nitrogen-Doped Vertically Oriented Graphene toward Versatile Electrode-Related Applications

Abstract

The direct growth of vertically oriented graphene (VG) on low-priced, easily accessible soda-lime glass can propel its applications in transparent electrodes and energy-relevant areas. However, graphene deposited at low temperature (∼600 °C) on the catalysis-free insulating substrates usually presents high defect density, poor crystalline quality, and unsatisfactory electrical conductivity. To tackle this issue, we select high borosilicate glass as the growth substrate (softening point ∼850 °C), which can resist higher growth temperature and thus afford higher graphene crystalline quality, by using a radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) route. A nitrogen doping strategy is also combined to tailor the carrier concentration through a methane/acetonitrile-precursor-based synthetic strategy. The sheet resistance of as-grown nitrogen-doped (N-doped) VG films on high borosilicate glass can thus be lowered down to ∼2.3 kΩ•sq −1 at a transmittance of 88%, less than half of the methane-precursor-based PECVD product. Significantly, this synthetic route allows the achievement of 30-inch-scale uniform N-doped graphene glass, thus promoting its applications as excellent electrodes in high-performance switchable windows. Additionally, such N-doped VG films were also employed as efficient electrocatalysts for electrocatalytic hydrogen evolution reaction.

Designing New‐Generation Piezoelectric Transducers by Embedding Superior Graphene‐Based Thermal Regulators

“…Furthermore, the I D / I G value for Sample IV (≈0.48, achieved through the designed two‐step synthetic strategy) is significantly lower than that for Sample III (≈0.88, by conventional PECVD), indicating its higher crystal quality or few amorphous carbon adsorptions, according to the published references. [ 6,42–44 ]…”

“…Furthermore, the I D /I G value for Sample IV (≈0.48, achieved through the designed two-step synthetic strategy) is significantly lower than that for Sample III (≈0.88, by conventional PECVD), indicating its higher crystal quality or few amorphous carbon adsorptions, according to the published references. [6,[42][43][44] The direct growth of graphene on various functional insulating substrates induces the formation of new-type hybrids, dramatically extending the application fields of graphene by combining the complementary properties of graphene and substrate. [6,42,44] To explore the internal growth mechanism, the CVD-derived hybrids were meticulously characterized via scanning electron microscopy (SEM).…”

“…[6,[42][43][44] The direct growth of graphene on various functional insulating substrates induces the formation of new-type hybrids, dramatically extending the application fields of graphene by combining the complementary properties of graphene and substrate. [6,42,44] To explore the internal growth mechanism, the CVD-derived hybrids were meticulously characterized via scanning electron microscopy (SEM). The cross-sectional microscopy images for a 3D/2D-graphene/AlN-ceramic sample are displayed in Figure 2d,e, as achieved via two-step CVD strategy, that is, ≈4 h confined-flow APCVD followed with ≈4 h PECVD.…”

“…Prominent progress regarding the direct chemical vapor deposition (CVD) growth of graphene have been made on functional insulating templates (Al 2 O 3 , SiO 2 , TiO 2 , and SrTiO 3 ). [42][43][44][45][46][47][48] These efforts bypass the complicated transfer technologies of graphene from conventional metal substrates, offering multitudinous applications of as-grown hybrid materials. In addition to Al 2 O 3 , AlN thermosensitive ceramic is characterized with polycrystalline structure, porous morphology, and negligible thermal storage capability, customarily serving as heat-dissipation material in various high-power devices.…”

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

“…g ., soda-lime glass), under relative low growth temperature ( e.g ., 500–600 °C). , The resultant vertically oriented graphene (VG) nanosheet films present distinctive physical properties, for example, nest-like morphologies, enlarged specific surface area, abundant exposed sharp edges, out-of-plane thermal and electrical conductivities, etc . − Nevertheless, relatively poor electrical conductivity is usually inevitable, impeding the practical applications of VG/glass hybrids as transparent conductive materials. For tackling this dilemma, various synthetic strategies have recently been proposed to reduce the sheet resistances of VG nanowalls films grown directly on glass substrates, , such as an ethanol-precursor-based PECVD route (on soda-lime glass at ∼600 °C) for efficiently removing the amorphous carbons, and a nitrogen doping process via a methane/acetonitrile-precursor-based PECVD route (on high borosilicate glass at ∼820 °C) for tailoring the carrier concentration …”