Moth-eye effect in hierarchical carbon nanotube anti-reflective coatings

Abstract Optical anti-reflection is achieved in natural surfaces by exploiting hierarchical surface morphology. Here, we show that single-walled carbon nanotube (SWCNT) coatings deposited on silicon (Si) realize a broad-band, omnidirectional, and nearly polarization-independent suppression of Si optical reflection, with an increase of film absorption. This is attributed to a biomimetic, hierarchical surface morphology, which introduces a graded refractive index–the so-called moth-eye effect. Moreover, the anti-reflective behavior can be tuned by varying the SWCNT film thickness. The SWCNT random networks are realized by a simple, rapid, reproducible, and inexpensive solution-processing technique and deposited on Si by a dry-transfer printing method, at room temperature. The technology may be used to coat arbitrary substrates such as optical instruments, radiometric applications, light and thermal sensors, solar cells, and light emitting diodes; thus improving the device absorption or emission of light, due to the film optical properties.

[1]  A. Djurišić,et al.  Optical properties of graphite , 1999 .

[2]  J. Teng,et al.  Design and fabrication of broadband ultralow reflectivity black Si surfaces by laser micro/nanoprocessing , 2014, Light: Science & Applications.

[3]  Jinan Zeng,et al.  Very black infrared detector from vertically aligned carbon nanotubes and electric-field poling of lithium tantalate. , 2010, Nano letters.

[4]  Drew A. Pommet,et al.  Optimal design for antireflective tapered two-dimensional subwavelength grating structures , 1995 .

[5]  J. Cox,et al.  Deposition and characterization of far-infrared absorbing gold black films. , 1993, Applied optics.

[6]  Satoshi Yasuda,et al.  A black body absorber from vertically aligned single-walled carbon nanotubes , 2009, Proceedings of the National Academy of Sciences.

[7]  L. Sangaletti,et al.  Steering the efficiency of carbon nanotube-silicon photovoltaic cells by acid vapor exposure: a real-time spectroscopic tracking. , 2015, ACS applied materials & interfaces.

[8]  J.-Q. Xi,et al.  Internal high-reflectivity omni-directional reflectors , 2005 .

[9]  R. Green,et al.  Ultra-high optical absorption efficiency from the ultraviolet to the infrared using multi-walled carbon nanotube ensembles. , 2013, Small.

[10]  G. Sun,et al.  Global pattern for the effect of climate and land cover on water yield , 2015, Nature Communications.

[11]  E. Fred Schubert,et al.  Nanostructured multilayer graded-index antireflection coating for Si solar cells with broadband and omnidirectional characteristics , 2008 .

[12]  I. Cacciotti,et al.  Multi-Fractal Hierarchy of Single-Walled Carbon Nanotube Hydrophobic Coatings , 2015, Scientific Reports.

[13]  Jeremy J. Baumberg,et al.  Omnidirectional absorption in nanostructured metal surfaces , 2008 .

[14]  M. Yoshida,et al.  Giant Circular Dichroism in Individual Carbon Nanotubes Induced by Extrinsic Chirality , 2013, 1308.6398.

[15]  J A Dobrowolski,et al.  Fourier-transform method for the design of wideband antireflection coatings. , 1992, Applied optics.

[16]  Philippe M. Fauchet,et al.  Dynamic etching of silicon for broadband antireflection applications , 2002 .

[17]  I. Cacciotti,et al.  Controlling the thickness of carbon nanotube random network films by the estimation of the absorption coefficient , 2015 .

[18]  Bharat Bhushan,et al.  Biomimetics: lessons from nature–an overview , 2009, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[19]  Y. Ohno,et al.  Considerably improved photovoltaic performance of carbon nanotube-based solar cells using metal oxide layers , 2015, Nature Communications.

[20]  Anders Kristensen,et al.  Black metal thin films by deposition on dielectric antireflective moth-eye nanostructures , 2015, Scientific Reports.

[21]  S. Maier.  Plasmonics: Fundamentals and Applications , 2007 .

[22]  Andrew R. Parker,et al.  Biomimetics of photonic nanostructures. , 2007, Nature nanotechnology.

[23]  J. Pendry,et al.  EFFECTIVE MEDIUM THEORY OF THE OPTICAL PROPERTIES OF ALIGNED CARBON NANOTUBES , 1997, cond-mat/9705110.

[24]  E. F. Schubert,et al.  Light‐Extraction Enhancement of GaInN Light‐Emitting Diodes by Graded‐Refractive‐Index Indium Tin Oxide Anti‐Reflection Contact , 2008 .

[25]  J. Akimitsu,et al.  Unconventional superconductivity in Y5Rh6Sn18 probed by muon spin relaxation , 2015, Scientific Reports.

[26]  S. Maruyama,et al.  Polarization dependence of the optical absorption of single-walled carbon nanotubes. , 2005, Physical review letters.

[27]  W H Southwell,et al.  Gradient-index antireflection coatings. , 1983, Optics letters.

[28]  P Yeh,et al.  Optical properties of stratified media with exponentially graded refractive index. , 1983, Applied optics.

[29]  Lijie Ci,et al.  Experimental observation of an extremely dark material made by a low-density nanotube array. , 2008, Nano letters.

[30]  Din-Guo Chen,et al.  Anti-reflection (AR) coatings made by sol–gel processes: A review , 2001 .

[31]  Qianfan Xu,et al.  Experimental demonstration of guiding and confining light in nanometer-size low-refractive-index material. , 2004, Optics letters.

[32]  Ado Jorio,et al.  Carbon Nanotubes: Advanced Topics in the Synthesis, Structure, Properties and Applications , 2007 .

[33]  Hung-chun Chang,et al.  Design of optical path for wide-angle gradient-index antireflection coatings. , 2007, Applied optics.

[34]  P. Maddalena,et al.  Observation of a photoinduced, resonant tunneling effect in a carbon nanotube–silicon heterojunction , 2015, Beilstein journal of nanotechnology.

[35]  M. Rubner,et al.  Reversibly erasable nanoporous anti-reflection coatings from polyelectrolyte multilayers , 2002, Nature materials.

[36]  V. Baier,et al.  High temperature resistant antireflective moth-eye structures for infrared radiation sensors , 2005 .

[37]  C. Pan,et al.  Improved broadband and quasi-omnidirectional anti-reflection properties with biomimetic silicon nanostructures. , 2007, Nature nanotechnology.

[38]  E. Fred Schubert,et al.  Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection , 2007 .

[39]  R Feder,et al.  Graded-index AR surfaces produced by ion implantation on plastic materials. , 1980, Applied optics.

[40]  N. S. Sariciftci,et al.  Semiconducting and Metallic Polymers , 2010 .

[41]  G. Fowles,et al.  Introduction to modern optics , 1968 .

[42]  H. Philipp,et al.  Optical Properties of Graphite , 1965 .

[43]  S. Nakamura,et al.  Vertically oriented GaN-based air-gap distributed Bragg reflector structure fabricated using band-gap-selective photoelectrochemical etching , 2005 .

[44]  Joachim P Spatz,et al.  Biomimetic interfaces for high-performance optics in the deep-UV light range. , 2008, Nano letters.

[45]  Michael S Strano,et al.  Exciton antennas and concentrators from core-shell and corrugated carbon nanotube filaments of homogeneous composition. , 2010, Nature materials.

[46]  Maurizio Boscardin,et al.  Record efficiency of air-stable multi-walled carbon nanotube/silicon solar cells , 2016 .

[47]  M. Hutley,et al.  The Optical Properties of 'Moth Eye' Antireflection Surfaces , 1982 .

[48]  D. Ugarte,et al.  Aligned Carbon Nanotube Films: Production and Optical and Electronic Properties , 1995, Science.

[49]  M. Tomozawa,et al.  Porous silica materials as low-k dielectrics for electronic and optical interconnects , 2001 .

[50]  Min Gu,et al.  Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy , 2014, Light: Science & Applications.

[51]  L. Sangaletti,et al.  Direct Evidence of Chemically Inhomogeneous, Nanostructured, Si− O Buried Interfaces and Their Effect on the Efficiency of Carbon Nanotube/Si Photovoltaic Heterojunctions , 2013 .

[52]  Peter Sutter,et al.  Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells , 2015, Nature Communications.

[53]  Di Zhang,et al.  Super black and ultrathin amorphous carbon film inspired by anti-reflection architecture in butterfly wing , 2011 .