Broadband Solar Absorber Technologies for Renewable Energy

Broadband solar absorbers harness sunlight across ultraviolet, visible and near-infrared wavelengths, converting photon energy into heat or electricity with high efficiency. Central to their design are nanostructured architectures—such as metal–insulator–metal stacks, plasmonic metasurfaces and emerging two-dimensional materials—that exploit resonant absorption while suppressing thermal emission. Incorporating refractory materials and robust dielectric layers extends operational temperatures and enhances durability. Advances in photonic resonance control, including Fabry–Pérot cavities and surface plasmon modes, have broadened absorption bandwidths from around 300 nm to beyond 2500 nm. Data-driven design strategies, notably machine learning, are accelerating optimisation by predicting optical response across parameter spaces. These developments underpin applications in solar thermal collection, thermophotovoltaics, photodetectors and photothermal catalysis, offering scalable pathways to decarbonise energy systems worldwide.

Research from Nature Portfolio

Recent studies have employed advanced metasurface architectures to achieve near-unity absorptivity across ultra-broad spectral ranges. One design utilises patterned titanium nitride and chromium resonators atop a dielectric stack to deliver over 96 % average absorption from ultraviolet to mid-infrared wavelengths, maintaining performance above 95 % for incident angles up to 60° and both polarisations. Another work integrates graphene and metallic resonators in symmetric and asymmetric metasurfaces, achieving above 90 % absorption across visible and near-infrared bands and employing machine learning to predict optical behaviour as a function of geometry and angle, thereby reducing simulation time and guiding rapid optimisation. A third approach demonstrates plus-shape slotted metamaterials with multi-resonator coupling, yielding continuous absorption above 90 % from UV through NIR and leveraging regression algorithms to forecast performance for novel configurations, pointing towards accelerated design cycles for solar thermal harvesters.

Broadband Solar Absorber Technologies for Renewable Energy publication trend

The graph below shows the total number of articles in broadband solar absorber technologies for renewable energy across all publications each year (not limited to Nature Index journals).

Technical terms

Broadband absorption: High optical absorption across a wide spectral range, typically from ultraviolet to near-infrared wavelengths.

Metasurface: A two-dimensional array of subwavelength resonators engineered to manipulate electromagnetic waves at specific frequencies.

Metamaterial: Artificially structured materials with tailored electromagnetic responses not found in bulk materials, achieved via periodic nanoscale inclusions.

Surface plasmon resonance: Collective oscillations of free electrons at a metal–dielectric interface, leading to strong light confinement and enhanced absorption.

Fabry–Pérot resonance: Optical resonance arising from multiple reflections between parallel reflective surfaces, enhancing absorption at specific wavelengths.

Polarisation independence: Uniform absorption efficiency regardless of the electric field orientation of incident light.

Incidence-angle insensitivity: Maintenance of high absorption performance over a range of light incidence angles.

MXene: A class of two-dimensional transition metal carbides, nitrides or carbonitrides with tunable optical and electrical properties.

References

1. Highly efficient, perfect, large angular and ultrawideband solar energy absorber for UV to MIR range. Scientific Reports (2022).
2. Graphene-based metasurface solar absorber design with absorption prediction using machine learning. Scientific Reports (2022).
3. Ultra-broadband, wide-angle plus-shape slotted metamaterial solar absorber design with absorption forecasting using machine learning. Scientific Reports (2022).
4. Refractory Ultra-Broadband Perfect Absorber from Visible to Near-Infrared. Nanomaterials (2018).
5. Visible and Near-Infrared Broadband Absorber Based on Ti3C2Tx MXene-Wu. Nanomaterials (2022).
6. A Highly Efficient Infinity-Shaped Large Angular- and Polarization-Independent Metamaterial Absorber. Symmetry (2023).