Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection

Xi, Jinghui; Schubert, M.; Kim, Jong Kyu; Schubert, E. Fred; Chen, Minfeng; Lin, Shawn‐Yu; Liu, W.; Smart, J.

doi:10.1038/nphoton.2007.26

Cited by 1,120 publications

(694 citation statements)

References 28 publications

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“…This shape resembles the form of a quintic profile, which is close to the optimum profile for a gradedindex anti-reflection coating [26][27][28] . To compare it with our model of random nanopillars profiles, we added a quintic profile n eff ¼ n air þ n chitin À n air ð Þ ð 10ð z h max Þ 3 À 15ð z h max Þ 4 þ 6ð z h max Þ 5 Þ with a height h max ¼ 800 nm (red dashed line) to Fig.…”

Section: Dt Is the Complementary Error Function The Remaining Fractisupporting

confidence: 55%

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

2015

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The glasswing butterfly (Greta oto) has, as its name suggests, transparent wings with remarkable low haze and reflectance over the whole visible spectral range even for large view angles of 80°. This omnidirectional anti-reflection behaviour is caused by small nanopillars covering the transparent regions of its wings. In difference to other anti-reflection coatings found in nature, these pillars are irregularly arranged and feature a random height and width distribution. Here we simulate the optical properties with the effective medium theory and transfer matrix method and show that the random height distribution of pillars significantly reduces the reflection not only for normal incidence but also for high view angles.

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Section: Dt Is the Complementary Error Function The Remaining Fractisupporting

confidence: 55%

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

2015

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“…The most straightforward approach places a single layer of intermediate optical index at the interface to create destructive interference in the reflected light, providing full antireflection at a single wavelength, l ¼ 4n i Á t, with material thickness (t) and refractive index n i ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffi n S Á n A p , where n S and n A are the refractive indices of the substrate and air, respectively. Increasing broadband coverage, for application in transparent window coatings [2][3][4][5] , military camouflage 6 or solar cells [7][8][9][10][11][12][13][14][15] , is possible using thin-film multilayer schemes 16 . An alternative to thin-film-coating strategies instead patterns the interface at subwavelength dimensions, creating an effective medium between the substrate and air, with n i changing gradually from n A to n S 10,11,17 .…”

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confidence: 99%

Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells

et al. 2015

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Materials providing broadband light antireflection have applications as highly transparent window coatings, military camouflage, and coatings for efficiently coupling light into solar cells and out of light-emitting diodes. In this work, densely packed silicon nanotextures with feature sizes smaller than 50 nm enhance the broadband antireflection compared with that predicted by their geometry alone. A significant fraction of the nanotexture volume comprises a surface layer whose optical properties differ substantially from those of the bulk, providing the key to improved performance. The nanotexture reflectivity is quantitatively well-modelled after accounting for both its profile and changes in refractive index at the surface. We employ block copolymer self-assembly for precise and tunable nanotexture design in the range of B10-70 nm across macroscopic solar cell areas. Implementing this efficient antireflection approach in crystalline silicon solar cells significantly betters the performance gain compared with an optimized, planar antireflection coating.

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“…Because of the unavailability of optical materials with very low refraction indices that closely match the refraction index of air, such broadband antireflection coatings have not been realizable (pH: 8 and 11). Also, they demonstrate their potential for antireflection coatings by virtually eliminating Fresnel reflection from an AlN-air interface over a broad range of wavelengths 22 . The film of pH: 11 may be useful IR detectors because of higher transmission after the 700 nm wavelength (% T > 90) 23 .…”

Section: Resultsmentioning

confidence: 96%

Optical and Structural Properties of Natural MnSeO4 Mineral Thin Film

Kariper

2017

Mat. Res.

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Manganese selenite (MnSeO 4 ) crystalline thin film has been produced with chemical bath deposition on substrates (commercial glass). Properties of the thin film, such as transmittance, absorption, and optical band gap and refraction index have been investigated via UV/VIS Spectrum. The structural properties of orthorhombic form have been observed in XRD. The structural and optical properties of MnSeO 4 thin films, deposited at different pH levels were analyzed. Some properties of the films have been changed with the change of pH level, which has been deeply investigated. The grain size of MnSeO 4 thin film has reached its highest value at pH 9. The refraction index and extinction coefficient of MnSeO 4 thin films were measured to be 1.53, 2.86, 2.07, 1.53 (refraction index) and 0.005, 0.029, 0.014, 0.005 (extinction coefficient) for grain sizes 21, 13, 26, and 5 nm respectively. The band gaps (Eg) of the films were measured to be 2.06, 2.57, 2.04, and 2.76 eV for the grain sizes mentioned above. The value of dielectric constant at pH 10 was calculated as 1.575.

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Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection

Cited by 1,120 publications

References 28 publications

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells

Optical and Structural Properties of Natural MnSeO4 Mineral Thin Film

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