As a result, a number of groups have pursued routes towards plasmon-enhanced OPVs that incorporate spherical metal NPs into the interfacial layer between the electrodes and activelayer, typically embedding them in the poly (3, 4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT: PSS) layer.[7, 10, 11] Indeed, we have previously demonstrated enhancements in device performance by embedding gold nanospheres in both the rear and front charge-selecting interfacial layers of the devices.[12] However, a modest enhancement with final PCE (7.5%) was achieved. Moreover, even seemingly innocuous treatments of the PEDOT: PSS layer can alter its charge transport properties at the surface.[13] Therefore, a key step in developing a truly general method for using plasmonic light management to enhance the performance of OPVs is to demonstrate that the method can be used with multiple kinds of polymers and nanoparticles, while exhibiting characteristics consistent with improved photon harvesting. Here, we explore universal methods to incorporate plasmonic metal particles into OPV devices and demonstrate a combination of three key advances: 1) we utilize tunable silver nanoprisms with optical properties superior to those of silver and gold nanospheres; 2) we demonstrate compatibility of the same approach with multiple state-of-the-art OPV active layers; and 3) we provide spectroscopic and device evidence that the resulting enhancements are consistent with enhanced optical absorption. These advances allow us to report an appreciable enhancement in light harvesting BHJ layers associated with the optical effects resulting in a significant improvement in maximum PCE to 9.0%, up from 7.7% for control devices without plasmonic nanoprisms, a relative improvement of nearly 18%. Not only does this result represent the highest combination of overall efficiency and relative improvement achieved via plasmonic optical effects to date, but more importantly, permits facile tailoring of the plasmon resonance bands in a method compatible with multiple active layers. Here, we focus on the incorporation of silver nanoprisms with various sizes and shapes, prepared by various synthetic methods, with different thin-film OPVs by employing a dual interfacial layers strategy [12] allowing for incorporation of complementary, spectrally tunable, nanoprism layers at both the top and bottom interfaces (Figure 1B). Our desire to replace the more common gold nanospheres with silver nanoprisms is in part due to the fact that smaller gold spheres have relatively high ratios of absorption loss to scattering and comparatively modest local field enhancement factors (while incorporating larger gold spheres with stronger scattering into devices can be troublesome due to their potential for shorting).[14] Compared to spheres, anisotropic silver and gold nanostructures such as

Organic photovoltaics (OPVs) have attracted enormous attention as a potential alternative renewable energy source because of their light weight, conformability, and low-cost solution processability.[1] Recent results surpassing 10% power conversion efficiency (PCE) represent a major milestone [2] and give hope for prospects of commercialization. Ideally, a photovoltaic absorber should be thick enough to absorb most of the incoming sunlight. However, an obstacle for current OPV materials is the decrease in fill factor with increasing thicknesses associated with recombination losses and low charge carrier mobilities.[3] Consequently, the internal quantum efficiency tends to decrease with film thickness, and many current generation high-performance polymer solar cells use active layers of sub …