Core-Shell Plasmonic Material for Broadband Solar Absorption
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Solution Overview
Problem
Noble metal nanospheres' plasmonic absorption bandwidth is inherently narrow, limited to visible light, resulting in low energy utilization of sunlight, and broadening this bandwidth either reduces absorption intensity or requires a large number of costly noble metal particles.
Innovation Solution
A plasmonic material with a core-shell structure, where the core is a noble metal nanomaterial and the shell is non-stoichiometric copper sulfide (Cu2-xS), achieving full spectrum absorption (300-2500 nm) through plasmon coupling, using a small amount of noble metal nanoparticles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If noble metal nanospheres are used for solar absorption, then photothermal conversion efficiency is improved, but absorption bandwidth is limited to visible light only
Solution Approach 1:
The patent employs a core-shell structure where a noble metal core (Au, Ag, or alloy) is coated with a copper sulfide shell (Cu2-xS). This composite structure combines the advantages of both materials: the noble metal provides strong plasmonic absorption in the visible region, while the copper sulfide shell extends absorption into the near-infrared region, achieving full solar spectrum coverage (300-2500 nm) without sacrificing photothermal conversion efficiency
Solution Approach 2:
The patent utilizes localized surface plasmon resonance (LSPR) effects by adjusting the geometry, assembly state, and dielectric environment of the nanomaterials. By controlling the core-shell structure parameters (size, shape, composition ratio), the absorption spectrum is tuned to cover the entire solar range while maintaining high photothermal conversion efficiency
2Adaptability or versatility
If absorption bandwidth is broadened by adjusting geometry and assembly state, then absorption spectrum is extended, but absorption intensity is reduced
Solution Approach 1:
The core-shell composite structure resolves this contradiction by combining two materials with complementary absorption characteristics. The noble metal core maintains strong absorption intensity through LSPR in the visible region, while the copper sulfide shell adds near-infrared absorption, achieving both broad bandwidth and high intensity simultaneously
Solution Approach 2:
Different parts of the core-shell structure serve different functions: the noble metal core is optimized for visible light absorption with high intensity, while the copper sulfide shell is optimized for near-infrared absorption. This local functional differentiation allows the overall structure to achieve broad spectrum absorption without compromising intensity in either region
3Adaptability or versatility
If a large number of noble metal particles are assembled in porous substrate, then absorption bandwidth is broadened by plasmonic hybridization, but material cost increases significantly
Solution Approach 1:
The core-shell composite structure reduces noble metal usage by combining a small amount of noble metal core with a copper sulfide shell. The shell material is much cheaper and contributes to near-infrared absorption, thereby broadening the absorption bandwidth while significantly reducing the quantity of expensive noble metal required compared to assembling large numbers of pure noble metal particles
Solution Approach 2:
The copper sulfide shell acts as an intermediary that extends the optical response of the noble metal core into the near-infrared region. This intermediary layer enables plasmonic hybridization effects without requiring large assemblies of noble metal particles, thus broadening absorption bandwidth while minimizing noble metal consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables broad absorption without sacrificing intensity, enhancing photothermal conversion and accelerating water evaporation, making it suitable for solar-driven interfacial desalination with high energy utilization efficiency.
Implementation Method 1
the plasmonic noble metal nanomaterials have exceptionally strong light absorption capacity and high photothermal conversion efficiency due to their localized surface plasmon resonance effect. The plasmon is the collective oscillations of free charge carriers in response to incident light
Implementation Method 2
extending the light absorption to the near-infrared region by adjusting their geometry, assembly state and surrounding dielectric environment
Implementation Method 3
combining and coupling the plasmonic absorption of noble metal nanomaterials in visible light and the plasmonic absorption of copper sulfide in near-infrared light
Implementation Method 4
The non-radiative decay of plasmons produces high-energy hot carriers, which can rapidly raise the temperature of the crystal lattice and surrounding medium through the electron/phonon and phonon/phonon couplings
Data Source
AI summary
A plasmonic material, a solar absorber containing the plasmonic materials, and preparation and application thereof. The plasmonic material is a material with a core-shell structure in which the core is a noble metal nanomaterial and the shell layer is non-stoichiometric copper sulfide with the general formula Cu2-xS, where 0<x≤1. The plasmonic materials can broaden the absorption bandwidth by combining and coupling the plasmonic absorption of noble metal nanomaterial in visible light and the plasmonic absorption of copper sulfide in near-infrared light. The absorption can be broadened and enhanced without sacrificing the absorption intensity with only a small amount of metal nanoparticles, thus enhancing photothermal conversion and accelerating water evaporation The solar absorber containing the plasmonic materials has a fast water evaporation rate under sunlight.