Smooth TiO2 Thin Films Grown by Aqueous Spray Deposition for Long-Wave Infrared Applications

MRS Advances ◽  
2018 ◽  
Vol 3 (5) ◽  
pp. 255-260 ◽  
Author(s):  
Sarmad Fawzi Hamza Alhasan ◽  
Seth R. Calhoun ◽  
Hussain Abouelkhair ◽  
Vanessa C. Lowry ◽  
Robert E. Peale ◽  
...  
Keyword(s):  
Spray Deposition ◽  
Low Cost ◽  
Large Area ◽  
Tio2 Thin Films ◽  
Long Wave ◽  
Nano Crystalline ◽  
Metal Insulator Metal ◽  
Pressure Chemical ◽  
Indirect Band Gap ◽  
Long Wave Infrared

ABSTRACTSelf-assembled TiO2 films deposited by aqueous-spray deposition were investigated to evaluate morphology, crystalline phase, and infrared optical constants. The Anatase nano-crystalline film had ∼10 nm characteristic surface roughness sparsely punctuated by defects of not more than 200 nm amplitude. The film is highly transparent throughout the visible to wavelengths of 12 μm. The indirect band gap was determined to be 3.2 eV. Important for long-wave infrared applications is that dispersion in this region is weak compared with the more commonly used dielectric SiO2 for planar structures. An example application to a metal-insulator-metal resonant absorber is presented. The low-cost, large-area, atmospheric-pressure, chemical spray deposition method allows conformal fabrication on flexible substrates for long-wave infrared photonics.

Earth Long-Wave Infrared Emission, New Ways to Harvest Energy

2015 ◽  
pp. 1-25
Author(s):  
Luciano Mescia ◽  
Pietro Bia ◽  
Onofrio Losito
Keyword(s):  
Low Cost ◽  
Dielectric Substrate ◽  
Infrared Emission ◽  
Long Wave ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Recent Developments ◽  
Potential Applications ◽  
Long Wave Infrared ◽  
Thz Antennas

This chapter summarizes the physical properties of THz antennas, provides a summary of some of the most important recent developments in the field of energy harvesting of Earth long-wave infrared radiation, discusses the potential applications and identifies the future challenges and opportunities. In particular, a THz antenna is designed in order to transform the thermal energy, provided by the Sun and re-emitted from the Earth, in electricity. The proposed antenna is a square spiral of gold printed on a low cost dielectric substrate. Simulations have been conducted in order to investigate the behavior of the antenna illuminated by a circularly polarized plane wave with an amplitude chosen according to the Stefan-Boltzmann radiation law. Moreover, these THz antennas could be coupled with other components to obtain direct rectification of T radiation. As a consequence, these structures further optimized could be a promising alternative to the conventional photovoltaic solar cells.

scholarly journals Far-infrared bands in plasmonic metal-insulator-metal absorbers optimized for long-wave infrared

MRS Advances ◽  
2019 ◽  
Vol 4 (11-12) ◽  
pp. 667-674 ◽  
Author(s):  
Rachel N. Evans ◽  
Seth R. Calhoun ◽  
Jonathan R. Brescia ◽  
Justin W. Cleary ◽  
Evan M. Smith ◽  
...  
Keyword(s):  
Ground Plane ◽  
Wavelength Region ◽  
Wave Model ◽  
Far Infrared ◽  
Resonance Wavelength ◽  
Surface Structures ◽  
Metal Insulator ◽  
Long Wave ◽  
Metal Insulator Metal ◽  
Long Wave Infrared

ABSTRACTMetal–insulator–metal (MIM) resonant absorbers comprise a conducting ground plane, a dielectric of thickness t, and thin separated metal top-surface structures of dimension l. The fundamental resonance wavelength is predicted by an analytic standing-wave model based on t, l, and the dielectric refractive index spectrum. For the dielectrics SiO2, AlN, and TiO2, values for l of a few microns give fundamental resonances in the 8-12 μm long-wave infrared (LWIR) wavelength region. Agreement with theory is better for t/l exceeding 0.1. Harmonics at shorter wavelengths were already known, but we show that there are additional resonances in the far-infrared 20 - 50 μm wavelength range in MIM structures designed to have LWIR fundamental resonances. These new resonances are consistent with the model if far-IR dispersion features in the index spectrum are considered. LWIR fundamental absorptions are experimentally shown to be optimized for a ratio t/l of 0.1 to 0.3 for SiO2- and AlN-based MIM absorbers, respectively, with TiO2-based MIM optimized at an intermediate ratio.

Earth Long-Wave Infrared Emission, New Ways to Harvest Energy

2017 ◽  
pp. 1875-1899
Author(s):  
Luciano Mescia ◽  
Pietro Bia ◽  
Onofrio Losito
Keyword(s):  
Low Cost ◽  
Dielectric Substrate ◽  
Infrared Emission ◽  
Long Wave ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Recent Developments ◽  
Potential Applications ◽  
Long Wave Infrared ◽  
Thz Antennas

This chapter summarizes the physical properties of THz antennas, provides a summary of some of the most important recent developments in the field of energy harvesting of Earth long-wave infrared radiation, discusses the potential applications and identifies the future challenges and opportunities. In particular, a THz antenna is designed in order to transform the thermal energy, provided by the Sun and re-emitted from the Earth, in electricity. The proposed antenna is a square spiral of gold printed on a low cost dielectric substrate. Simulations have been conducted in order to investigate the behavior of the antenna illuminated by a circularly polarized plane wave with an amplitude chosen according to the Stefan-Boltzmann radiation law. Moreover, these THz antennas could be coupled with other components to obtain direct rectification of T radiation. As a consequence, these structures further optimized could be a promising alternative to the conventional photovoltaic solar cells.

scholarly journals Theoretical Uniformity Analysis and Improvement of Spray Deposition by Mixing Nozzles with Heating Conditions

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 81
Author(s):  
Xuran Dong ◽  
Xiaolong Pan ◽  
Xianxian Gao ◽  
Haisheng Fang
Keyword(s):  
High Speed ◽  
Heating Temperature ◽  
Spray Deposition ◽  
Low Cost ◽  
Spray Coating ◽  
Deposition Process ◽  
Test Method ◽  
Large Area ◽  
Orthogonal Test Method ◽  
Experimental Trials

Spray coating is widely used in the manufacture of deposited layers of electronic devices due to its unique advantages of high-speed deposition over a large area. To improve the spray deposition process for further low-cost and uniform production, the uniformity of the spray deposition should be systematically investigated. The current study, however, mainly focuses on the experimental trials with few numerical directions especially for the mixing nozzle sprayers with heating conditions. In the paper, we conduct a theoretical study on the uniformity of the internal and external mixing nozzles. The influencing factors include the initial angle, the total ink flow rate, the transporting gas velocity and the distance from the nozzle to the substrate. Then, the orthogonal test method is adopted to obtain the optimal combination of the parameters. Finally, the effects of different heating modes on the uniformity have been further studied. The results show that these factors influence the uniformity with the two types of nozzles to a different degree. The evaporation of the atomized droplets can effectively improve the uniformity in a certain temperature range. The heating temperature with the highest uniformity is various depending on the heating modes, which should be carefully addressed during the actual production.

Spray deposited TiO2 thin films for large-area TiO2/p-Si heterojunction solar cells

2021 ◽  
Author(s):  
Manas R. Samantaray ◽  
Prashant Kumar Gautam ◽  
Dhriti Sundar Ghosh ◽  
Nikhil Chander
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Spray Deposition ◽  
Minority Carrier Lifetime ◽  
Open Circuit ◽  
Deposition Technique ◽  
Large Area ◽  
Tio2 Thin Films ◽  
Heterojunction Solar Cells ◽  
Si Substrates

Abstract Carrier selective contacts (CSC) have the potential to lower the cost of photovoltaic (PV) cells. In the present work p-Si/TiO2 heterojunction solar cells have been fabricated using titanium dioxide (TiO2) as an electron-selective layer. Thin uniform anatase TiO2 films have been deposited using a commercially viable spray deposition technique over large area Si substrates. With a simple architecture of Al (200 nm fingers)/Al (15 nm thin film)/TiO2/c-Si(p)/Ag (200 nm), a highest conversion efficiency of 1.56 % has been achieved for the TiO2 carrier selective contact based solar cell with an active area of ~3.84 cm2. The minority carrier lifetime value of the TiO2 coated Si wafer was found to be less than that of the uncoated wafer, indicating the inability of the anatase TiO2 layer to provide surface passivation. Suns-VOC measurements yielded comparable values of the implied open circuit voltage for both the uncoated and the TiO2 coated Si wafers. Spray deposition technique can be used for scalable fabrication of carrier selective contact based heterojunction solar cells.

Design of All-Dielectric Long-wave infrared Wide-angle Metalens

2021 ◽  
Author(s):  
Ning Zhang ◽  
Qingzhi Li ◽  
Jun Chen ◽  
Feng Tang ◽  
Jingjun Wu ◽  
...  
Keyword(s):  
Focal Length ◽  
Low Cost ◽  
Numerical Aperture ◽  
Single Layer ◽  
Industrial Processing ◽  
Monochromatic Imaging ◽  
Long Wave ◽  
Wavelength Scale ◽  
Long Wave Infrared ◽  
Sub Wavelength

Abstract Optical metasurfaces are two-dimensional arrays of nano-scatterers that modify optical wavefronts at subwavelength spatial resolution. They achieve the effect of focusing through phase control under a sub-wavelength scale, named metalens. They are poised to revolutionize optics by enabling complex low-cost systems. However, there are monochromatic severe aberrations in the metasurfaces. In this paper,the long-wave infrared optical system coma is eliminated through a single-layer metasurface. By changing the phase function,this metalens have a numerical aperture of 0.89,a focal length of 150 μm,and a field of view of 120° (0.4@60lp/mm) that enables diffraction-limited monochromatic imaging along the focal plane at a wavelength of 10.6μm. And the designed metasurface maintains a favorable MTF value at different angles. This equipment can be widely used in imaging and industrial processing.

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