High absorption broadband solar energy device and thermal emitter based on titanium metamaterials

As the energy crisis gradually becomes the main cause of global conflict, the utilization of solar energy is imperative for the well-being of the planet. Regarded as a renewable energy source by the scientific community, solar energy has become one of the most important areas of future energy exploration. This paper proposes a solar absorber design based on Ti with fractal geometry. The device is designed to optimize solar energy utilization, thereby achieving higher efficiency. It exhibits over 90 % absorption across the 446.5–2479.5 nm wavelength range, with a weighted average absorption rate of 92.47 % under AM1.5 conditions. The device also exhibits favorable thermal radiation characteristics, achieving thermal radiation efficiencies of 86.5 %, 88.66 %, and 90.07 % at temperatures of 1000 K, 1250 K, and 1500 K, respectively. Furthermore, the structure, material, and parameters of the solar absorber were modified to ascertain the impact of these factors on the absorption process. Finally, the absorber structure is designed to exhibit perfect symmetry in the X and Y directions, making the solar absorber proposed in this paper polarization independent. It boasts an average absorption efficiency of 91.01 %, maintaining this efficacy in both transverse electric (TE) and transverse magnetic (TM) modes up to an incidence angle of 60°. This work innovates by designing a titanium-based split ring structure. Its unique layout enhances the surface plasmon resonance effect in each corner, thereby broadening the bandwidth. Its good environmental adaptability indicates that the structure is suitable for solar energy absorption applications. As the energy crisis is gradually evolving into the main contradiction of the global conflict, for this reason, the utilization of solar energy is imperative for the well-being of the planet. It's regarded as renewable energy source, a classification that is widely accepted within the scientific community, has become one of the important directions for future energy exploration, this paper proposes a solar absorber design based on the Ti that incorporates a fractal geometry. This design is intended to optimize the utilization of solar energy, thereby achieving enhanced efficiency, the device demonstrates an absorption rate that surpasses 90 % across the wavelength spectrum ranging from 446.5 to 2479.5 nm, with a weighted average absorption of 92.47 % at AM1.5 condition, and extremely good thermal emission characteristics with thermal emission efficiencies of 86.5 %, 88.66 %, and 90.07 % at 1000 K, 1250 K, and 1500 K, respectively. Furthermore, modifications were made to the structure, material, and parameters of solar absorber to ascertain the impact of these factors on the absorption process. Finally, the absorber structure, meticulously designed to exhibit perfect symmetry in the X and Y directions, renders the solar absorber proposed in this paper polarization independent. It boasts an average absorption efficiency of 91.01 %, maintaining this efficacy in both transverse electric (TE) and transverse magnetic (TM) modes, extending up to incidence angles of 60°. The innovation of our work lies in the design of a Ti-based split-circle ring, the unique placement of which enhances the surface plasmon resonance effect at each corner and extends the bandwidth, while the excellent environmental adaptability suggests that the structure applies to solar absorption. • The average absorption rate of the structure based on Ti as the patch ring is 94.13 % in the wavelength range of 446.5 nm–2479.5 nm, and the band with absorption efficiency greater than 95 % is 1657.5 nm–2216 nm. • The average absorption efficiency of the structure is 92.47 % under AM1.5 conditions. • The structure has high thermal radiation efficiency of 86.5 %, 88.66 % and 90.07 % at 1000 K, 1250 K and 1500 K, respectively. • The unique layout of this ring structure based on metal titanium enhances the surface plasmon resonance effect of each angle, which is of reference significance for expanding the bandwidth. • The multilayer structure can be used as a solar absorber and a thermal emitter.