A transfer matrix approach to aid in the design and optimization of hybrid advanced passive structures for enhancing photovoltaic efficiency

The addition of a luminescent down-shifting (LDS) layer directly onto a photovoltaic (PV) cell introduces additional loss mechanisms within the system. The combination of non-ideal photo-luminescent materials encapsulated within a limited range of viable host materials, with the increased reflection losses arising from the newly created interface represent losses which must be overcome for LDS to offer an enhancement to the underlying cells efficiency. Exploiting the interaction between the highly enhanced electric fields established close to a metal nanoparticles (MNP's) surface is one route aimed at mitigating the poor optical properties of the luminophore-host combinations available. Alternative approaches, aimed at addressing the other loss mechanisms within such a system have gone relatively unexplored. Exploiting the non-ideal nature of the photo-luminescent materials available, offers a possibility of recycling the photons which previously did not undergo photoluminescence while also addressing the reflection losses through the inclusion of selectively reflecting optical structures. The hybrid device designs, incorporating single- and double layer-antireflection coatings composed of commonly available materials offer enhancements in the underlying PV cells performance of 8% -30% depending upon the design criteria established. The transfer matrix approach adopted allowed the impact of individual design considerations on the reflection suppression capabilities of the structure, as well as their impact on the underlying cells efficiency to be readily determined.