Localized surface plasmon resonance of Au?Cu alloy nanoparticles enhances the performance of polymer photovoltaic devices for outdoor and indoor applications

Organic semiconductors are receiving increasing attention in the field of solar energy because of their advantageous properties, including high absorption coefficients, mechanical flexibility, solution processability and low material costs [1?3]. Over the past years, the power conversion efficiencies (PCEs) of organic-based solar cells have been improved rapidly; the current certified world record is as high as 17.5% for organic photovoltaic devices (OPVDs) [4]. Their PCEs, however, still require further improvements to strive with inorganic photovoltaic devices. One of the obstacles to highly efficient OPVDs is the low mobilities of organic semiconductors; the thickness of the photoactive layers is usually limited in order to increase the charge collection efficiency, resulting in incomplete absorption of the photons from solar irradiation. To increase Au-Cu alloy nanoparticles (NPs) are synthesized for triggering localized surface plasmon resonance (LSPR) in organic photovoltaic devices (OPVDs). Because Cu is readily oxidized, alloying with Au enhances the chemical stability of the NPs, thereby simplifying the fabrication processes. The electrical characterizations indicate that the alloy NPs improve the device performance under both one-sun illumination and indoor lighting conditions due to the effects of LSPR. Finally, the result of the stability test reveals that the use of the Au-Cu NPs would not affect the device stability. We anticipate that the results in this work open up a new avenue for plasmonic-enhanced OPVDs featuring low cost, stable nanostructures.

Automated summary

Organic semiconductors are gaining attention in solar energy applications due to their high absorption coefficients, mechanical flexibility, solution processability, and low material costs. Although the power conversion efficiencies of organic-based solar cells have been rapidly improving, they still need further enhancements to compete with inorganic devices. The use of Au-Cu alloy nanoparticles to trigger localized surface plasmon resonance shows promising improvements in device performance without compromising stability.