Chang Sun, Jiaxing Huang, and colleagues, Northwestern University, Evanston, IL, USA, have found that Blu-ray movie discs can be converted into inexpensive templates for efficient light-trapping applications such as solar cells.

Blu-ray discs are pocked with quasi-random patterns of nanoscopic pits and islands to optimize data compression and error tolerance. Regardless of the information stored on the discs, the patterns are nearly optimized for photon management over the solar spectrum. Normally, optimizing quasi-random nanostructures make very expensive fabrication processes necessary to create the pre-designed, subwavelength nanostructures.

The researchers coated recorded discs with a silicone elastomer and transferred the patterns to a photoactive polymer PTB7:PC₇₁BM. Solar cells made this way absorb more light and convert it to electricity more efficiently than nonpatterned ones. Simulation suggests that Blu-ray patterns could be broadly applied for solar cells made of other materials.

• Repurposing Blu-ray movie discs as quasi-random nanoimprinting templates for photon management,
  Alexander J. Smith, Chen Wang, Dongning Guo, Cheng Sun, Jiaxing Huang,
  Nat. Commun. 2014.
  DOI: 10.1038/ncomms6517