Tao Liang,Enshan Liu,Minghui Li,Elena V. Ushakova,Stephen V. Kershaw,Andrey L. Rogach,Zikang Tang,Songnan Qu
In this work, we report a successful extension of the family of light-emitting colloidal carbon nanostructures to a number of different shapes and morphologies, namely, carbon nanorolls (CNRs) and carbon nanobelts (CNBs). Near infrared (NIR)-emissive CNRs were synthesized via a solvothermal fusion of carbon dots (CDs) triggered by a dehydration process of their surface functional groups. They appear in a form of short cylinders, with diameters ranging from 20 to 40 nm and cylinder lengths ranging from 7 to 20 nm. In ethanol solution, CNRs have a maximum absorption peak at 665 nm and a NIR emission band extending from 650 to 800 nm, with a photoluminescence quantum yield of 9.2%. Intriguingly, the rolled structure of CNRs can be uncoiled under 655 nm laser irradiation (power density 1 W·cm–2) of their solution in ethanol, forming CNBs with a width of 7–20 nm and lengths reaching several hundreds of nanometers, which is accompanied by a considerably decreased absorption band at 665 nm and a decreased NIR emission. This unfolding is ascribed to the decrease of the strength of interlayer hydrogen bonding, owing to the photothermally induced dehydration and further carbonization of the CNRs. Alongside the decreased NIR emission, CNBs exhibit enhanced green and red emissions under UV and green light excitation, respectively, which allows us to demonstrate multiple-level luminescence encryptions on a paper stamped with CNR- and CNB-inks.
Lu Wu,Chang Xu,Mingshuai Fan,Ping Tang,Rui Zhang,Shuaitao Yang,Lujun Pan,Yuezhen Bin
Flexible sensors have wide-ranging application prospects in the field of human health motion monitoring. However, it is still a challenge to design and prepare strain sensors with both high sensitivity and wide operating range. Inspired by the fiber connection structure of lotus root, the carbon nanocoils (CNCs) with large aspect ratio (acting as the lotus root fibers) is used as a conductive bridge to connect the fragile Ti 3 C 2 -MXene nanosheet layers, significantly enhancing the sensing range of the sensor. Waterborne polyurethane (WPU) encapsulated strain sensor (Ti 3 C 2 /CNCs/WPU) can achieve GF values and sensing ranges of 474 and 220%, respectively. In addition, this sensor shows reliable responses at different frequencies and can withstand more than 1000 stretch-release cycles. More importantly, the composite strain sensor can accurately sense and monitor different limb movements and human body motion states, showing broad application prospects in real-time human health detection.
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