Amorphous hydrogenated carbon coatings for thermal solar collectors

Thermal expansion coefficient of hydrogenated amorphous carbon

The coefficient of thermal expansion ~CTE! of hydrogenated amorphous carbon (a-C:H) was investigated as a function of the concentration of sp hybridization. The CTE, determined using the thermally induced bending technique, depends on the concentration of sp bonded carbon, increasing to the value of graphite as the sp concentration approaches 100%. By using a combination of the thermally induce...

Potential of carbon nanohorn-based suspensions for solar thermal collectors

The optical characterization is reported of a new fluid consisting of single wall carbon nanohorns and ethylene glycol for solar energy applications. Carbon nanohorns play a significant role in enhancing sunlight absorption with respect to the pure base fluid. The obtained results are compared with those obtained for fluids suspending more conventional carbon forms, i.e. carbon-black particles....

Nitrogen modification of hydrogenated amorphous carbon films

The effect of nitrogen addition on the structural and electronic properties of hydrogenated amorphous carbon ~a-C:H! films has been characterized in terms of its composition, sp bonding fraction, infrared and Raman spectra, optical band gap, conductivity, and paramagnetic defect. The variation of conductivity with nitrogen content suggests that N acts as a weak donor, with the conductivity firs...

Growth mechanism of amorphous hydrogenated carbon

Amorphous hydrogenated carbon (a-C:H) films offer a wide range of applications due to their extraordinary material properties like high hardness, chemical inertness and infrared transparency. The films are usually deposited in low temperature plasmas from a hydrocarbon precursor gas, which is dissociated and ionized in the plasma and radicals and ions impinging onto the surface leading to film ...

Thermally induced evolution of hydrogenated amorphous carbon