Abstract

Carbon nanotubes modified copper oxide nanocomposite (CNTs-CuO NC) selective absorbers were prepared through a sol-gel method by varying weight percentage of CNTs and coated on aluminum (Al) substrates using a dip coating technique to form thin films (TFs). The surface morphology of CNTs-CuO NC TF examined by scanning electron microscopy disclosed linear arrangement of CNTs-CuO NC TF with average particle diameter of 200 +/- 30 nm. The X-ray diffractometer analysis of the CNTs-CuO NC TF revealed the presence of CuO in monoclinic crystal structure. Moreover, the X-ray diffractometer analysis disclosed good crystalline quality of the CNTs-CuO NC TF and average crystallite size of the CuO and CNTs-CuO NC TF was found to be 69.38 and 85.94 nm, respectively. The energy dispersive X-ray spectrum of CNTs-CuO NC TF ascertained the presence of Cu, O and C elements with atomic weight proportion of 71.07, 21.61 and 7.32 %, respectively. The functional groups investigation by FTIR spectroscopy exhibited distinct spectral features of CNTs and the peaks observed at 516.78 and 588.70 cm-1 correspond to the characteristic vibrations of metal-oxygen (M-O) bond that indicates the presence of CuO in the hybrid CNTs-CuO NC TF. The optical property of the CNTs-CuO NC TF with CNTs weight proportion of 0.5 % inspected through UV-Vis-NIR spectroscopy exhibited high solar absorptance and thermal emittance values of 85.9 and 4.3 %, respectively. The observed highest solar selectivity value of 19.98 suggests that the CNTs-CuO NC TF coating can be apparently used as solar selective absorber. Carbon nanotubes modified copper oxide selective absorber thin films (CNTs-CuO NC TFs) were prepared using sol-gel method. These thin films, coated on aluminum substrates, exhibited good crystalline quality and linear arrangement. The observed high solar selectivity value (19.98) of CNTs (0.5 wt %)-CuO NC TF suggests its potential use as selective absorber. image