Quantifying the Usefulness of Oxide-Encapsulated Silver Nanoparticles in Semiconducting Films

Abstract

Incorporating plasmonic nanoparticles (NPs) in an organic solar cell (OSC) can improve device performance. In our simulation studies, at NP resonance, absorption in poly(3-hexythiophene)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM) can be increased by encapsulating 50 nm Ag NPs with Al2O3, HfO2, MoO3, and SiO2. At Ag NP resonance, when the oxide thickness is significant enough, oxides with high relative permittivity induces a higher electric field enhancement at the metal/dielectric interface. This is translated to improved absorption in the polymer layer. By integrating against AM1.5G, overall absorption in P3HT/PCBM is improved when incorporating Ag NPs encapsulated with a thin oxide shell into the polymer film. However, polymeric absorption loss is induced for oxide-encapsulated Ag NPs if MoO3 and SiO2 shells are more than 5 nm. For Al2O3 and HfO2, Ag NPs should not be encapsulated with shells thicker than 10 nm. Modeling studies are also extended to absorption in a CH3NH3PbI3 perovskite layer. It is revealed that both Al2O3 and HfO2 have an optimal shell thickness of about 20 nm to ensure maximum absorption in CH3NH3PbI3. The results can be utilized as a useful guideline when designing photovoltaics from an optical point of view.