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In recent decades, there has been a strong and growing interest in developing strategies to engineer materials with tailored optical and plasmonic properties. In the plethora of geometries studied and proposed in the literature, nanostructures based on cluster arrangements known as "plasmonic molecules" (PMs) have shown several interesting properties and represent potential candidates to implement different types of opto-plasmonic applications. In this paper, we examine a fractal PM (FPM), analyzing its properties by numerical simulations based on the finite element method (FEM). Next, periodic arrangements of the FPM in two different configurations were fabricated by an electron beam lithography (EBL) process, and their plasmonic features were experimentally characterized. Our numerical simulations are in good agreement with the experimental results. Our study highlights noticeable features of the analyzed PM, such as multi-resonant and anisotropic properties, which can be exploited to design plasmonic devices with customized optical characteristics also compatible with multiple sensing applications. We tested the performance of our FPM for surface-enhanced Raman spectroscopy (SERS) sensing, realizing a functionalized system for the specific detection of the SARS-CoV-2. We tested different concentrations of the virus, obtaining a limit of detection (LOD) of 88 PFU/mL, lower than that of commercial rapid kits. Our results demonstrate that the proposed plasmonic nanopatterns are promising to develop integrable devices for a sensitive SERS detection in a portable point-of-care (POC) platform. [ABSTRACT FROM AUTHOR]

In this study, we present an innovative approach to increase the quantum yield and wavelength sensitivity of photomobile polymer (PMP) films based on azobenzene by doping the polymer matrix with noble metal nanoparticles. These doped PMP films showed faster and more significant bending under both UV as well as visible and near-infrared light regardless of whether it was coherent, incoherent, polarized, or unpolarized irradiation, expanding the potential of PMP-based actuators. To illustrate their practical implications, we created a proof-of-concept model of power generation by coupling it to flexible piezoelectric materials under simulated sunlight. This model has been tested under real operating conditions, thus demonstrating the possibility of generating electricity with variable light exposure. Additionally, our synthetic protocol is solvent-free, which is another benefit of environmental relevance. Our research lays the groundwork for the development of sunlight-sensitive devices, such as photomechanical actuators and advanced photovoltaic modules, which may break ground in the thriving field of smart materials. We are confident that the presented findings will contribute to the ongoing discourse in the field and inspire additional advances in renewable energy applications., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)