Influence of temperature-induced copper diffusion on degradation of selective chromium oxy-nitride solar absorber coatings

M. Kotilainen, M. Honkanen, K. Mizohata, P. Vuoristo

    Research output: Contribution to journalArticleScientificpeer-review

    17 Citations (Scopus)


    Temperature-induced copper diffusion process and its influences on optical degradation and long-term stability of solar absorber coatings on copper substrates were investigated at intermediate temperatures of 248-500. °C. The studied absorbers were sputtered chromium oxy-nitride absorbers having tin oxide anti-reflection coatings. The absorbers were aged by means of thermal accelerated ageing studies and short-period heat treatments up to 500. °C for two hours.Ageing mechanisms and degradation of the absorbers were analysed before and after the ageing studies by optical measurements (solar absorptance with a UV/Vis/NIR spectrophotometer and thermal emittance by FTIR spectrophotometry), microstructural analysis using a field-emission scanning electron microscope (FESEM) equipped with an energy dispersive X-ray spectrometer (EDS) and a transmission electron microscope (TEM) with an EDS, composition by time-of-flight elastic recoil detection analysis (TOF-ERDA) and an X-ray photoelectron spectroscope (XPS), and adhesion by tensile test. The relation between optical degradation and diffusion mechanisms was studied using optical modelling and simulation. The results clearly revealed the mechanism of outward copper diffusion: diffusion of copper substrate atoms into the coating and through the coating to the surface, formation of copper oxide islands on the surface of the coating, and formation of voids in the substrate surface. The relation between the diffusion mechanisms and increase in thermal emittance of the absorber surface was demonstrated.

    Original languageEnglish
    Pages (from-to)323-332
    Number of pages10
    JournalSolar Energy Materials and Solar Cells
    Publication statusPublished - 2016
    Publication typeA1 Journal article-refereed


    • Coating
    • Copper
    • Diffusion mechanisms
    • Solar absorber
    • Thermal diffusion
    • Void growth

    Publication forum classification

    • Publication forum level 2

    ASJC Scopus subject areas

    • Renewable Energy, Sustainability and the Environment
    • Electronic, Optical and Magnetic Materials
    • Surfaces, Coatings and Films


    Dive into the research topics of 'Influence of temperature-induced copper diffusion on degradation of selective chromium oxy-nitride solar absorber coatings'. Together they form a unique fingerprint.

    Cite this