Tunable graphene-coated refractory nitride nanomatryoshka in C-151 dye for improved solar absorption

Abstract

Plasmonic nanostructures provide an effective route to enhance light–matter interaction in advanced photovoltaic architectures. This work reports a numerical analysis of localized surface plasmon resonance (LSPR), near-field electromagnetic enhancement, absorption efficiency, and the spectral tunability of the laser dye 7-amino-4 (trifluoromethyl) coumarin (C-151) when coupled with a graphene-coated nanomatryoshka architecture. The multilayer nanomatryoshka consists of a CdSe/Cu2O core, a TiN/HfN plasmonic shell, and a graphene outer layer. The optical characteristics are systematically examined as functions of semiconductor core radius, plasmonic shell thickness, and graphene chemical potential. The analysis demonstrates pronounced LSPR excitation accompanied by strong near-field electromagnetic enhancement and broadband absorption enhancement driven by plasmon–exciton interaction and graphene-enabled spectral tuning. Unlike conventional noble-metal plasmonic systems, nanomatryoshka structures based on TiN and HfN demonstrate superior thermal stability and spectral robustness while preserving strong plasmonic behavior. The resulting enhancement in optical absorption underscores the effectiveness of graphene-integrated refractory plasmonic nanostructures for efficient light harvesting and advanced photovoltaic and optoelectronic applications.