Enhanced evanescent mode light trapping in organic solar cells and other low index optoelectronic devices

A new light‐trapping scheme is described based on tunnelling evanescent waves. The scheme is particularly suitable for low index materials such as organic solar cells and polar inorganic semiconductors such as CdTe, or dielectric layers containing, for example, upconverters. The 4 n 2 macroscopic limit on light trapping, where n is refractive index, can be exceeded by a large margin using the new scheme.