When two chemists based in China couldn’t reproduce experiments in their paper on opal films, they retracted it.
As the retraction note explains:
In this article we report a method to fabricate 2D TiO2–WO3 composite inverse opal films via a mechanical co-assembly route with a template of polystyrene spheres. Upon repeating the experiments described, we found that this was not an effective method for forming the films; often the film was broken or did not form at all.
The note also explains why the experiment didn’t work:
Continue reading Chemists pull non-reproducible paper on method to make opal films