Quantitative adhesion characterization of antireflective coatings in multijunction photovoltaics

Adhesion of antireflective coatings in multijunction photovoltaics

“…Results of the adhesion measurements are presented in Fig. 2, including the 3-digit label for each sample [16]. The differences in processing and materials lead to significant differences in adhesion energy, with measurements falling in a range from less than 0.5 J/m 2 to 8 J/m 2 .…”

“…These new test structures are shown in Fig. 1, with each composite beam consisting of 180µm thick germanium bonded to 820µm thick titanium (Grade 5 alloy, 5x50mm) using a high-strength epoxy (Loctite E-20NS) under high pressure [16]. The epoxy was cured at room temperature to avoid developing stress from thermal misfit.…”

“…Existing methods are prone to fracture within the substrate, resulting in very low measurement yield therefore necessitating the creation of a new testing method. We report here on a recent study in which we developed a composite dual cantilever beam (cDCB) adhesion test, and applied it to the measurement of adhesion of AR coatings deposited on top of state of the art multijunction PV cells [16]. As is fairly typical in multijunction PV systems [7], [17], [18], Al 2 O 3 /TiO 2 AR layers are used, which were deposited via both high or low energy deposition methods.…”