A study of defects in ultra-thin transparent coatings on polymers

Electroplating to visualize defects in Al2O3 thin films grown using atomic layer deposition

“…The defects may be related to surface roughness as discussed for the copper substrates or caused by particle contamination on the original substrate. The particles may act as a mask to prevent the deposition of the ALD film [10,24,25]. The particles may then be displaced to yield a pinhole defect.…”

A new encapsulation solution for flexible organic solar cells

“…It can be seen that near the so-called critical thickness, d C (here about 15 nm) the OTR drops drastically, yet cannot be improved significantly by further increasing the thickness. It has been observed that nanometersize structural defects present in the barrier coating, which are mainly caused by intrinsic or extrinsic surface roughness [25] account for this limited performance of single-layer gas barrier.…”

Influence of structural feature of aluminum coatings on mechanical and water barrier properties of metallized PET films

“…In a previous study, Chatham 3 measured coating thicknesses by X-ray fluorescence, calibrated by chemical analysis, multiple beam interferometry, electrical resistance measurements, and X-ray diffraction line broadening. In the present work, three coated films have been investigated by different methods, i.e.…”

“…Figure 13(a) shows a strong decrease of permeance with aluminum thickness to about 40 nm, then a constant residual permeation is observed. The literature 3 report that a residual permeation exist even when the barrier inorganic coatings are relatively thick (¼70 nm); Sobrinho et al 3 attribute this phenomenon to the presence of microscopic defects in the SiO 2 or SiN coatings. Bonnebat 20 indicates a residual permeation to water vapor [$1.2 Â 10 À9 kg/(m 2 s)] for PET metallized with aluminum for an optical density (OD) of 3.5 which corresponds to 54 nm.…”

“…To overcome this problem, oxide thin coatings on polymer substrates, mainly used for food and medical packaging, have been studied by a number of workers. [3][4][5] These studies mainly showed that oxide coatings are characterized by the presence of defects which control the oxygen and water vapor permeability of the coated film. Comprehensive knowledge of the barrier mechanisms is thus required to select the most appropriate material.…”