solar energy, photovoltaics, light trapping, nanoparticle scattering
We consider the enhancement of an organic (P3HT) photovoltaic with conductive nanoparticles of various shapes, sizes and spacing as top-reflectors; used in conjunction with a periodic and a pseudo-random back-reflector. The surface for the pseudo-random back-reflector was generated from a uniformly distributed process of white spectrum, which was mapped into a Gaussian distribution, then filtered to impose a bandwidth or time constant, and then mapped back into a uniform distribution. We illustrate cases in which the periodic back-reflector(P, comprised of triangles) can provide enough resonances to outperform the pseudo-random reflector for P3HT photovoltaic devices illuminated by solar spectra. Specifically, for a given top-reflector (i.e., given a specific shape, spacing and size of nanoparticles in an array) the choice of a periodic back-reflector can, in some cases, yield a higher short-circuit current for a P3HT PV than the choice of a pseudo-random back-reflector. Even in instances, within our grid of parameters, where the pseudo-random surfaces give exceptional enhancements these are shown to actually be due to an “accidental” resonance which arises because the surface is pseudo-random rather than perfectly random.