Optically Graded Ultra Dark Absorber for Visible and Near-infrared Wavelength Range.

ABSTRACT: Near perfect absorbers find application in many areas including solar cells, energy harvesting and antireflection coatings for space applications. Here we report the use of optical gradation concept to fabricate a near perfect absorber on etched Si wafer. As a proof of concept, 99.4% absorption is achieved in the broad range of 300 nm to 2000 nm. Moreover, absorption capacity of optically graded surface remains higher than 99% up to beam incident angle of 50°. While carbon nanotubes (index ~1.1) are used as top layer, subsequent layers with increasing optical index across the thickness are chosen so as to satisfy zero reflection condition on multilayered assembly. Inward bending of incident beam and total internal reflection of reflected beam caused due to optical index gradient contribute

SUBMITTER: Agnihotri PK 

PROVIDER: S-EPMC6098028 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature