Solar energy is one of the most promising renewable energy sources, and the development of photovoltaic converters (PVs) plays a key role in its efficient utilisation. However, the efficiency of current solar panels is limited by a number of factors, including insufficient ability to absorb light over a wide spectral range, reflection losses, and limitations in converting absorbed light into electrical energy. Metamaterials, artificially engineered materials with unique electromagnetic properties, can provide innovative solutions to overcome these limitations and achieve significant improvements in PVs efficiency. This work focuses on conceptual modelling of the application of metamaterials to improve light absorption and efficiency of solar panels, and analyses the potential advantages of different types of metamaterials [1].

The research is based on conceptual modelling and analysis of the possibilities of using different types of metamaterials to optimise the characteristics of PVs. This approach includes the study of the theoretical basis for the interaction of metamaterials with electromagnetic radiation, as well as modelling of their integration into the PVs structure. The study is based on a review of scientific publications, analytical reports and experimental data in the fields of nanotechnology, optics and photovoltaics, and the use of electromagnetic theory principles and numerical modelling. Various metamaterial designs, including plasmonic structures, photonic crystals, metasurfaces and multilayer structures, are considered and their potential to improve light absorption in different spectral ranges, as well as their impact on PVs parameters, are evaluated. The modelling is carried out taking into account the physical, electrical and optical properties of the materials used, as well as the conditions of their integration into the PVs structure, including such parameters as layer thickness, refractive index, and geometrical dimensions of the structures [2].

One of the key challenges is to ensure efficient absorption of sunlight over a wide spectral range covering the UV, visible and infrared regions. Conventional materials and coatings used in PVs have limited effectiveness in this context, especially when considering different angles of light incidence [3]. Metamaterials such as plasmonic structures and metasurfaces can be designed to induce resonant absorption of light in a given wavelength range. The use of multilayer structures or metamaterials with gradient properties (e.g., varying period or shape of elements) can allow broadband absorption to be achieved. This design flexibility can maximise light absorption, thereby increasing the generation of charge carriers and the overall efficiency of the PVs.

Another important aspect affecting the efficiency of PVs is the reduction of light reflection from their surface. Conventional anti-reflective coatings based on the principle of thin film interference have limited effectiveness and work only in a narrow range of wavelengths and angles of incidence. In contrast, metamaterials can be used to create effective anti-reflective coatings that reduce light reflection over a wide range of wavelengths and angles of incidence. This is achieved by using sub-wavelength sized structures that are able to mimic an effective medium with a smoothly varying refractive index, allowing the impedance between the air medium and the FEP semiconductor material to be gradually matched, minimising reflection.

Metamaterials can be used to enhance the local electromagnetic field in the active layer of FEPs, which directly affects the efficiency of charge carriers generation and conversion of light into electricity. Plasmonic structures, in particular, can concentrate and focus light in a thin layer of semiconductor, thereby increasing the intensity of light-material interaction and photogeneration efficiency. In addition, the use of resonant metamaterials can enhance the absorption of light in certain spectral ranges, increasing the quantum yield of the PVs

Metamaterials can be designed to control light propagation within the solar panel. Conventional PVs often face problems with reflection light loss, as well as suboptimal light distribution within the active region. Metamaterials can reduce such losses by redirecting light into the active region of the PVs, and also facilitate more efficient utilisation of thin layers of semiconductor materials. This can lead to the development of thinner, lighter, and more flexible PVs that have high efficiency and low manufacturing costs [4]. To illustrate the potential of metamaterials, in the context of improving the efficiency of FETs, a comparative Table 1 is provided to illustrate the expected light absorption, reflection, and overall efficiency when using different types of metamaterials.

Table 1

Potential characteristics of PVs with metamaterials.

The use of metamaterials in PVs has the potential to significantly increase their efficiency, opening new perspectives for the development of solar energy. Conceptual modelling and theoretical calculations show that metamaterials integrated into the PVs structure can increase light absorption by 30-50% compared to conventional technologies [5]. Combining different types of metamaterials optimised for different tasks (broadband absorption, reflection reduction, field enhancement, light control) can allow even higher values to be achieved. Moreover, metamaterials can reduce losses in thin layers of semiconductor materials, which makes it promising to use thinner and cheaper layers, reducing the overall cost of solar panel production and increasing their flexibility [6].

MISIS National Research Technological University is conducting research on the application of metasurfaces to improve the efficiency of solar cells. These metasurfaces, which are thin films with a periodic structure of nanoscale elements, modify the properties of light at the interface. MISIS developers model and optimise different types of metasurfaces made of metallic or dielectric nanostructures deposited on a transparent substrate. The parameters of these structures, such as shape, size and period, are selected to maximise the absorption of sunlight in the desired spectral ranges. Experimental implementation involves fabrication of the structures by lithography and thin film sputtering techniques, followed by integration into a thin film solar cell structure. Studies have shown that the use of metasurfaces leads to increased light absorption, especially in low absorption spectral regions, and can also provide anti-reflection properties, which generally improves solar cell performance and efficiency. However, there are challenges in scaling up production, the high cost of fabricating nanostructures, the need for metasurfaces to be stable under operating conditions, and difficulties in integrating into existing manufacturing processes. At the moment, despite active research, commercial implementation of metasurfaces developed at MISIS in industrial solar panels has not yet been realised. Further research is aimed at overcoming these difficulties and realising the potential of this technology to improve the efficiency of solar energy.

Conceptual modelling of the application of metamaterials in photovoltaic converters demonstrates a high potential to significantly improve their efficiency and reduce their cost. Metamaterials offer new opportunities to improve light absorption, reduce reflection, enhance the local electromagnetic field, and control light propagation in PESs. Further research involving experimental implementation of the proposed concepts and optimisation of metamaterial parameters could lead to next-generation solar panels with improved performance, lower cost, higher availability, and higher efficiency, thus contributing significantly to the diffusion of renewable energy.