High yield synthesis of carbon nanofibers in an environmental friendly route

Photoresponse of Carbon Nanofiber-Based Photodetector and Its Enhancement on CuNi Nanoparticle Adsorption

We explore the photodetection properties of a carbon nanofiber (CNF)-based p-CNF/n-Si heterojunction device in the 400-800 nm wavelength range and investigate the changes brought in by adsorption of CuNi (CN) nanoparticles on the CNFs. The nanoparticles and CN-CNF nanocomposites were synthesized by using chemical hydrothermal routes. The p-type semiconducting nature of the CNFs and nanocomposites was determined using X-ray photoelectron (XPS) and UV-vis spectroscopies. The p-CNF/n-Si device is found to be better than many carbon-nanotube-based devices in terms of its peak responsivity (0.6 A/W) and gain (1.6), with an acceptably moderate peak detectivity (1.3 × 109 Jones) at 450 nm and a -5 V bias. The p-CN-CNF/n-Si device displays an appreciable enhancement in the photoresponse with respect to the p-CNF/n-Si device, with a peak responsivity of 2.8 A/W, peak detectivity of 9.4 × 109 Jones, and gain of 8. With the aid of valence band XPS and Raman spectra, the enhancement is explainable in terms of a CN to CNF charge transfer and the resulting increase in the built-in potential at the heterojunction.

Silica embedded carbon nanosheets derived from biomass acorn cupule for non-enzymatic, label-free, and wide range detection of α 1-acid glycoprotein in biofluids

In this work, we demonstrate the first report on a low-cost, non-enzymatic, label-free electrochemical sensing of alpha-1-acid-glycoprotein (α₁GP) biomarker in biofluids using silica embedded carbon nanosheets (SEC) derived from acorn cupules biomass. The SEC/GCE sensor exhibits low detection limit (LOD) of 30 ng/mL (LOD = 3 s/m) which is far below the lowest physiological concentration of α₁GP and a wide linear detection range from 100 ng/mL to 10 mg/mL which covers entire clinical concentration range reported for various diseases like cancer, sepsis, etc. The sensing mechanism of the sensor relies on the direct electrooxidation of sialic acid from the α₁GP structure which hinder the interfacial electron-transfer process of [Fe (CN)₆]^3-/4- redox probe at the electrode-electrolyte interface. The sensor exhibits excellent selectivity and stability towards detection of α₁GP which is ascribed to the presence of embedded silica nanoparticles on the surface of the carbon nanosheets. The successful determination of α₁GP in the simulated blood serum sample with good recovery percentage (i.e., from ∼94.03% to ∼103.50%) proves the feasibility of the sensor towards clinical applications. The overall efficacy of the sensor proves it as a promising low-cost, sustainable, and non-enzymatic platform for a wide variety of bioanalytical applications.