Efficient poly(3-hexylthiophene)-fullerene derivative bulk heterojunction photovoltaic devices using unique self-assembled layer of Ag nanoparticles with controllable particle-to-particle spacing

摘要

Among various types of solar cells, organic solar cells open an excellent opportunity for point-of-use energy harvesting. Organic solar cells have become a focus of research due to their potential for low cost, large-area, and high-throughput. Although organic solar cells have improved rapidly from very low efficiencies to moderate efficiencies of ~5%, the overall performance of organic solar cells is not yet high enough for commercial opportunities. In order to improve the efficiency of organic solar cells, one approach, addressed in this paper, will be to yield increased optical absorption and photocurrent generation over a broad range of visible wavelengths by inducing surface plasmon waves through careful control of the nanoparticle's properties. However, size and shape of conventionally formed nanoparticles vary over a wide distribution which could distort the plasmonic resonance by broadening their spectral enhancement. MetaMateria Partners synthesized metal nanoparticles below 10 nm by using a liquid processing technique which leaves the outer surface conformally coated with appropriate organic units. It is demonstrated that these coatings stabilize the nanoparticle and inhibit its propensity to agglomerate. In this work, we discussed plasmon-enhanced polymer solar cells using unique self-assembled layer of highly uniform size of Ag nanoparticles with controllable particle-toparticle spacing. It is also of great interest to theoretically investigate the impact of plasmonic materials (i.e., Ag nanoparticles in our study) on the performance of organic solar cells. This will be illustrated via the finite-difference time-domain algorithm, which is very suited to the analysis of plasmonic materials due to its robustness and highly geometrical flexibility.