title: Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics.
abstract: We present here a broadband, wide-angle, and polarization-independent nearly perfect absorber consisting of mirror-backed nanoporous alumina. By electrochemically anodizing the disordered multicomponent aluminum and properly tailoring the thickness and air-filling fraction of nanoporous alumina, according to the Maxwell-Garnet mixture theory, a large-area dark alumina can be made with excellent photothermal properties and absorption larger than 93% over a wide wavelength range spanning from near-infrared to ultraviolet light, i.e. 250 nm-2500 nm. The measured absorption is orders of magnitude greater than other reported anodized porous alumina, typically semi-transparent at similar wavelengths. This simple yet effective approach, however, does not require any lithography, nano-mixture deposition, pre- and post-treatment. Here, we also envisage and theoretically investigate the practical use of proposed absorbers and/or photothermal converters in integrated thermoelectronic and/or thermophotovoltaic energy conversion devices, which make efficient use of the entire spectrum of ambient visible to near-infrared radiation.
authors.affiliation: Division of Computer, Electrical, and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST) Thuwal 23955-69100, Saudi Arabia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Farhat
authors.affiliation: Department of Mechanical Engineering, National Kaohsiung University of Applied Science (KUAS), Kaohsiung 80778, Taiwan, Republic of China.
authors.forename: Tsung-Chieh
authors.initials: TC
authors.lastname: Cheng
authors.affiliation: Department of Electrical Engineering, University of Minnesota, Duluth, Minnesota 55812, USA.
authors.forename: Khai Q
authors.initials: KQ
authors.lastname: Le
authors.affiliation: Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202, USA.
authors.forename: Mark Ming-Cheng
authors.initials: MM
authors.lastname: Cheng
authors.affiliation: Division of Computer, Electrical, and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST) Thuwal 23955-69100, Saudi Arabia.
authors.forename: Hakan
authors.initials: H
authors.lastname: Bağcı
authors.affiliation: Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202, USA.
authors.forename: Pai-Yen
authors.initials: PY
authors.lastname: Chen
references.citation: Science. 2011 May 6;332(6030):702-4
references.pmid: 21551059
references.citation: Nano Lett. 2009 Mar;9(3):1139-46
references.pmid: 19193041
references.citation: Opt Express. 2009 Aug 17;17(17):15145-59
references.pmid: 19687992
references.citation: Opt Express. 2011 Jan 17;19(2):1301-9
references.pmid: 21263671
references.citation: Science. 1995 Jun 9;268(5216):1466-8
references.pmid: 17843666
references.citation: Sci Rep. 2014 Nov 24;4:7181
references.pmid: 25418040
references.citation: Appl Opt. 1985 Dec 15;24(24):4493
references.pmid: 18224235
references.citation: Sci Rep. 2015 Oct 09;5:15137
references.pmid: 26450563
references.citation: Nano Lett. 2012 Mar 14;12(3):1443-7
references.pmid: 22309161
references.citation: Phys Rev Lett. 2011 Jul 22;107(4):045901
references.pmid: 21867022
references.citation: Nat Commun. 2013;4:1643
references.pmid: 23535664
references.citation: Nanotechnology. 2015 Apr 24;26(16):164002
references.pmid: 25824491
references.citation: Nat Commun. 2011;2:517
references.pmid: 22044996
references.citation: Nat Mater. 2010 Mar;9(3):205-13
references.pmid: 20168344
references.citation: Nanotechnology. 2009 Oct 7;20(40):405202
references.pmid: 19738308
references.citation: Nanotechnology. 2007 Oct 3;18(39):395702
references.pmid: 21730427
references.citation: Nano Lett. 2013 Apr 10;13(4):1736-42
references.pmid: 23517407
references.citation: Opt Express. 2013 Dec 2;21(24):29938-48
references.pmid: 24514545
references.citation: Nature. 2012 Dec 6;492(7427):86-9
references.pmid: 23222613
references.citation: Nature. 2013 Nov 14;503(7475):209-17
references.pmid: 24226887
references.citation: Small. 2015 Apr;11(13):1526-30
references.pmid: 25381957
references.citation: Nat Nanotechnol. 2014 Feb;9(2):126-30
references.pmid: 24441985
references.citation: Phys Rev Lett. 2011 Mar 25;106(12):123902
references.pmid: 21517317
references.citation: Nature. 2012 Sep 20;489(7416):414-8
references.pmid: 22996556