Nanolayered Wavelength-Selective Narrowband Thermal Emitters for Solar Thermophotovoltaics

Abstract

To enhance the efficiency of a solar thermophotovoltaic system, one of the challenges is to develop a thermal emitter with narrowband emission at a selected wavelength to efficiently match the bandgap of a bottom photovoltaic cell. Here, we propose a nanolayered narrowband thermal emitter with a-SiN x and a-SiN y O z alternatively stacked nanolayers deposited on a polished silicon substrate covered by metallic molybdenum. The fabricated Si-Mo-SiN x /SiN y O z emitters exhibit a good narrowband absorption with an absorptance of above 90% at the designed emission wavelength based on a Tamm plasmon polariton, while the absorption spectra can be tuned by simply changing the thickness of the multilayers. Due to the large imaginary part of the dielectric function of Mo as well as the better stability compared with tungsten (W), a suppressed absorption as low as 1.4% can be achieved within the wavelength region of 2–7 μm and the fabricated emitters exhibit a high resistance to high-temperature treatment in an air atmosphere. The simulated solar thermophotovoltaic system efficiency reaches 28.9% under a solar concentration of 1000 based on the proposed emitter. Such a nanolayered wavelength-selective thermal emitter can be potentially applied in high-performance thermophotovoltaic systems.

Ultrathin Titanium Nitride Epitaxial Structures for Tunable Infrared Plasmonics

“…According to the recent theoretical and experimental studies, nanostructured TiN is an excellent broadband sunlight absorber due to strong plasmonic resonance ranging from 300 to 1300 nm, corresponding to the major sunlight spectral composition. One of the remaining major challenges is to develop a tunable thermal emitter with narrowband emission at a selective wavelength to match the bandgap of a bottom photovoltaic cell . Here, we demonstrate that plasmonic metasurfaces consisting of ultrathin TiN nanoribbons can be used as the desired tunable thermal emitters with narrowband resonances for both NIR and MIR wavelength regions.…”

“…The SQ limitation originates from the broadband nature of the solar spectrum and the semiconductor bandgap: Photons are not absorbed if the incident photon energy is less than the semiconductor bandgap, while photons with energy greater than the bandgap are absorbed with some energy loss due to fast electron–hole pair relaxation to the band edges . To overcome this limitation (broad solar spectrum), the concept of the solar thermophotovaltic (STPV) system has been proposed and demonstrated by including an intermediate light absorption (broadband)/emission (narrowband) element between the sunlight and the solar cell. – In essence, this intermediate element acts as an alternative “Sun” for solar cells, which is designed to absorb the entire solar spectrum , and emit a narrowband spectrum tailored to match with the desired semiconductor photovoltaic element . The utmost advantage of STPV is that all solar energy is converted into electrical energy and the overall conversion efficiency can be tremendously boosted. – …”

“…44−49 In essence, this intermediate element acts as an alternative "Sun" for solar cells, 45 which is designed to absorb the entire solar spectrum 17,25 and emit a narrowband spectrum tailored to match with the desired semiconductor photovoltaic element. 50 The utmost advantage of STPV is that all solar energy is converted into electrical energy and the overall conversion efficiency can be tremendously boosted. 47−49 However, the progress of the SPTV system has been slow due to the lack of reliable and sustainable optical materials, which can operate at high temperatures.…”

Transparent p–n Junction in Cu2O/ZnS/ZnO Core–Shell Nanoarrays via In Situ Sulfuration for Enhanced Photovoltaic Stability

“…The exhaustion and shortage of nonrenewable resources have recently emerged as urgent issues; therefore, the discovery and exploration of renewable resources are crucial in solving these issues. − Owing to factors such as the wide range of access channels, sufficient energy reserves, and environmental friendliness, , solar energy-based photoelectric devices have become the most effective and reliable technology to address these issues. − However, current research in the field solar energy-based photoelectric devices is primarily focused on the ultimate goal of enhancing solar efficiency. Moreover, these nontransparent solar cells cannot be used in windows, smart buildings, or automobiles, which restrict their wide applicability. , Therefore, developing transparent photovoltaic devices with balanced photovoltaic conversion and transparency is crucial. − Accordingly, to date, a series of wide bandgap semiconductor photovoltaic devices, such as SnO 2 -based and TiO 2 -based devices, has been developed.…”

CuI/BaSnO3 Quantum Dot/ZnSnO3 Perovskite-based Transparent p–n Junction for Photovoltaic Enhancement

“…With the rapid growth in energy demand and environmental pollution, developing green renewable energy sources has become a crucial research topic. Solar energy, with its abundant reserves, cleanliness, and low cost, has gained considerable attention and has been extensively studied as a promising approach for power generation, − particularly through solar cells owing to their high efficiency and convenience of use. − For example, silicon and perovskite solar cells have shown great potential for development. However, long-term stability and toxicity issues associated with organic and inorganic hybrid perovskite solar cells pose serious challenges for their practical applications. − Moreover, while full-spectrum absorption is advantageous for achieving high photovoltaic conversion efficiency (PCE), it hinders wide-ranging applications, − such as in smart windows.…”