Transparent Hard Coatings with SiON-Encapsulated N-Doped Carbon Dots for Complete UV Blocking and White Light Emission

Abstract

The solid-state hard encapsulation of carbon dots (CDs) can introduce an additional dimension for the tuning of their optical properties and effective promotion of multifunctional applications as well. In this study, simple hydrothermal and softsintering processes have been demonstrated to obtain silicon oxynitride-encapsulated N-doped carbon dots (SiON@NCDs) as well as organosilane-functionalized NCDs (OSi-NCDs). The surface-decorating long alkyl chains on NCDs help to prevent luminescence quenching in solid state and emit blue to orange color while forming a smooth film coating on the substrate. Interestingly, these OSi-NCDs can be readily converted into SiONencapsulated NCDs (SiON@NCDs) and form a smooth, hard, and visible light transparent coating on a glass surface after soft sintering. This hard coating has the ability to emit white light and 100% block all types of toxic UV light (UV-A, B, and C). The process reported here provides a unique strategy to modulate the NCD luminance properties from blue to white light emission (WLE) by transforming the organosilane matrix together with the NCDs themselves, possibly modified at their surface defects or functional groups. The transformation process involves the conversion of organosilane into a SiON hard-coat matrix via the reaction with the amine surface groups on NCDs. Subsequently, the hard-coatembedded NCD films emit WLE under UV excitation with good color stability and adjustable correlated color temperature (CCT) from warm white to cool white (3900−7300 K) depending upon their thicknesses. The process proposed here can be adopted for glass hard coating for white light emission (WLE) and UV-light blocking applications. Also, with our proposed hard encapsulation scheme, NCDs are endowed with long-term stability in harsh environmental conditions, which enables these materials for practical applications in many fields, including automotive, illumination industrial sectors, and luminescent solar cells (solar cell windows).

One-Step Hydrothermal Synthesis of Nitrogen-Doped Carbonized Polymer Dots with Full-Band Absorption for Skin Protection

“…Hess et al 38 used citric acid and PEI to synthesize carbon dots in the UVA band. Barman et al 39 used citric acid, ethylenediamine (EDA), and hydrothermal hydrochloric acid to synthesize UVA-absorbing carbon dots. In many reports, the CPDs synthesized from biomass or citric acid are used as UV absorbers.…”

Critical Level of Nitrogen Incorporation in Silicon Oxynitride Films: Transition of Structure and Properties, toward Enhanced Anticorrosion Performance

“…They have especially garnered attention since early 2000s as high-k replacements for the classical SiO2 gate dielectrics. 4 Their denser network in comparison to SiO2 lends them promising scratch-resisting, encapsulation, anti-corrosion and ion diffusion-limiting properties, finding them a spot in applications such as Na and B diffusion barriers in light emitting devices (LED) 5 , passivation film on surface acoustic wave devices 6 or at the TiO2/SiON/n-Si gate-stacks for advanced CMOS devices 7 , and for hard encapsulation of carbon dots 8 .…”

“…4 Their denser network in comparison to SiO 2 lends them promising scratch-resisting, encapsulation, anticorrosion, and ion diffusion-limiting properties, finding them a spot in applications such as Na and B diffusion barriers in light emitting devices (LED), 5 acoustic wave devices, 6 at the TiO 2 /SiON/n-Si gate-stacks for advanced CMOS devices, 7 and for hard encapsulation of carbon dots. 8 Their oxygen permeability and low water vapor transmission rate is also in demand for food packaging and electronic devices, 9 given their ability to prevent degradation or failure of chemically reactive electrodes or conductive components after exposure to humidity or oxygen. Although this material has been widely studied due to the above outstanding properties, further investigation of the structural and chemical disorder is of essence for new upcoming applications of SiO x N y .…”

Recyclable, UV-Blocking, and Radiative Cooling Multifunctional Composite Membranes

“…Carbon dots (CDs) have a wide range of absorption properties in the UV region, which make them a promising candidate for UV-shielding materials. Importantly, CDs have demonstrated excellent UV-shielding capabilities in the existing studies. − Currently, in order to realize the large-scale and sustainable application of CDs, sustainable carbon sources are essential. Further, carbohydrates, such as xylose, are considered to be one of the most promising carbon sources due to their abundance, renewable, economical, and nontoxic properties .…”