Au–Ag Alloy Nanocorals with Optimal Broadband Absorption for Sunlight-Driven Thermoplasmonic Applications

Abstract

Noble metal nanoparticles are efficient converters of light into heat but typically cover a limited spectral range or have intense light scattering, resulting in unsuited for broadband thermoplasmonic applications and sunlight-driven heat generation. Here, Au−Ag alloy nanoparticles were deliberately molded with an irregular nanocoral (NC) shape to obtain broadband plasmon absorption from the visible to the near-infrared yet at a lower cost compared to pure Au nanostructures. The Au−Ag NCs are produced through a green and scalable methodology that relies on pulsed laser fragmentation in a liquid, without chemicals or capping molecules, leaving the particles surface free for conjugation with thiolated molecules and enabling full processability and easy inclusion in various matrixes. Numerical calculations showed that panchromism, i.e., the occurrence of a broadband absorption from the visible to the near-infrared region, is due to the special morphology of Au−Ag alloy NCs and consists of a purely absorptive behavior superior to monometallic Au or Ag NCs. The thermoplasmonic properties were assessed by multiwavelength light-to-heat conversion experiments and exploited for the realization of a cellulose-based solar-steam generation device with low-cost, simple design but competitive performances. Overall, here it is shown how laser light can be used to harvest solar light. Besides, the optimized broadband plasmon absorption, the green synthetic procedure, and the other set of positive features for thermoplasmonic applications of Au−Ag NCs will contribute to the development of environmentally friendly devices of practical utility in a sustainable world.

Multigram-Scale Production of Hybrid Au-Si Nanomaterial by Laser Ablation in Liquid (LAL) for Temperature-Feedback Optical Nanosensing, Light-to-Heat Conversion, and Anticounterfeit Labeling

“…Due to a limited choice of basic materials with on-demand properties, integration of plasmonic and nanophotonic approaches within hybrid nanostructures is considered to be a key strategy for designing next-generation optoelectronic devices and optical sensors. − Meanwhile, along with their ability to integrate contrasting materials such as noble metals and semiconductors at the nanoscale, the related fabrication approaches should meet simultaneously a number of practical requirements such as scalability, simplicity, attractive production yield, etc. Beyond the multistep and expensive lithography-based approaches that can be potentially adopted for fabrication of hybrids, laser-assisted technologies have recently appeared as a promising route toward the environmentally friendly high-yield and inexpensive preparation of hybrid nanomaterials. − In particular, laser ablation in liquid (LAL) represents a flexible experimental approach that utilizes intense laser pulses to ablate a target material placed in a liquid medium. Spatially and temporally confined laser radiation can be used to create unique experimental conditions (high pressures and temperatures, fast quenching rates), also driving chemical interactions of the ejected nanomaterial with the surrounding liquid.…”

“…This provides a pathway for the preparation of nanomaterials with a wide range of morphologies, structures and compositions (including metastable and nonequilibrium phases) . Laser irradiation of LAL-generated dispersions can further expand the method functionality, allowing for the high-performance preparation of diverse hybrid nanomaterials for photovoltaics, , photothermal conversion, ,− catalysis, − nonlinear optics, sensing, − and medical applications. , …”

An Artificial Chameleon Skin for Dynamic Thermoregulation

“…Inspired by natural creatures, a wide variety of materials with specific functionalities such as high solar radiation absorption (e.g., carbon materials, [ 16–21 ] noble metal nanoparticles, [ 22,23 ] and structural materials [ 24–27 ] ) or reflection (whiteness [ 28,29 ] and metals [ 30,31 ] ) were reported. However, it is still a great challenge to design materials with both thermal adsorption and reflection functions to adapt to the dynamic surrounding environments.…”

Metamaterial ultra-wideband solar absorbers based on a multi-layer structure with cross etching

“…In recent years, more and more researchers have focused on achieving broadband absorption. [5][6][7][8] In 2012, Cui et al 9 designed an absorber that achieved more than 95% absorption in the infrared band. In 2013, Liang et al 10 designed a metamaterial absorber with a two-dimensional pyramid structure that achieved near-perfect absorption in the band of 1000-1400 nm.…”