Tailoring the physicochemical and mechanical properties of optical copper–cobalt oxide thin films through annealing treatment

Abstract

ÔØ Å ÒÙ× Ö ÔØTailoring the physicochemical and mechanical properties of optical copper cobalt oxide thin films through annealing treatment This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 Abstract Sol-gel dip-coated optical coatings, copper-cobalt oxides on aluminium substrates, were thermally treated at different annealing temperatures in the range 500 -650 °C. The resulting films were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrophotometry and nanoindentation techniques. The crystallinity of CoCu 2 O 3 enhanced significantly, with increasing annealing temperature from 500 to 650 °C, while the electronic structure and bonding states of the copper-cobalt oxides matrix remained unchanged. UV-Vis-NIR analysis showed that the solar absorptance (α) of the coatings changed with increasing of annealing temperature and an optimum α (84.4%) was achieved at 550 °C, which also coincides to the maximum tensile residual stress of the coating.Nanoindentation tests exhibited an increasing trend in both the hardness (H) and elastic modulus (E) of the coatings with increase in annealing temperature, although a slight decrease in the H/E ratio was also observed. The experimental studies were complemented by Finite Element Modelling (FEM). The results showed that, under mechanical loading, the stress and plastic deformation were concentrated within the coating layers. As such, the likelihood of delamination of the coating layer upon unloading would be reduced.

In situ characterization of Cu–Co oxides for catalytic application

“…The two major peaks of Cu 2p 3/2 and Cu 2p 1/2 are located at 934.2 and 954.0 eV, respectively. The splitting 18,19 energy is 19.8 eV, which agrees well the literature reported value 28 and indicates the formation of Cu 2+ . The satellite peakson the high energy side, arised from the shake-up transition by a ligand metal 3d charge transfer, also confirm the presence of Cu 2+ .…”

“…The component at binding energy of ~532 eV is assigned to the surface oxygen from a wide variety of species such as chemisorbed or dissociated oxygen or hydroxyl species as well as carbonate groups. [27][28][29] The small shoulder at around 533 eV could be due to subsurface Ospecies. 30 Among the Co-Cu oxides, both CuO and CuCo 2 O 4 exhibit abundant adsorbed and lattice oxygen, while a lot of lattice oxygen and certain amount of subsurface O-are observed in Co 3 O 4 .…”

Developments in the synthesis of flat plate solar selective absorber materials via sol–gel methods: A review

“…The absorptance of 83.4% (prior to the addition of an antireflection layer) was accomplished using 0.25 M copper acetate and 0.25 M cobalt chloride (Cu/Co ratio=1) with dip-speed 120 mm/min (four cycles). Nanoindentation test using the Berkovich indenter showed that the coatings have a high wear resistance [115][116][117].…”

Optical properties and thermal durability of copper cobalt oxide thin film coatings with integrated silica antireflection layer

“…Our coatings (before the addition of antireflection layer) exhibited promising absorptance properties as compared to other selective absorber materials synthesized from more complicated sol-gel process routes [25,26]. The light absorption selectivity behavior is due to the combination of factors of the intrinsic properties of coating, the film thickness and reflectivity properties of substrate [24]. However, to maximize the absorptance in UV-Vis range and to protect the coatings from any degradation due to external factors, an antireflection (AR) layer on the top of the absorber layer is, therefore, needed [27,28].…”

“…In our previous studies, we prepared copper cobalt oxide (Cu 2 CoO 3 ) thin film coatings deposited on highly reflecting aluminum substrate via a simple, cost-effective and environmentally-friendly sol-gel dip-coating route [21][22][23][24]. Our coatings (before the addition of antireflection layer) exhibited promising absorptance properties as compared to other selective absorber materials synthesized from more complicated sol-gel process routes [25,26].…”