Stray light, also known as optical noise, affects the performance of many optical devices. It can be reduced to a tolerable level by well-designed and well-baffled system or/and by using functional black coatings that are fabricated in a complex and costly process. Carbon nanotubes (CNTs) absorb light strongly, making them an ideal candidate for realizing a super black coating. CNT coatings were formed by spraying formulations composed of a silicon binder and low cost multiwalled CNTs on a pre-heated aluminum plate. The diffuse reflectance of the coatings in the VIS range (350-800. nm) was in the range of 2.6-5.11%, depending on the MWCNT concentration in the coating. In the NIR range (850-2400. nm), the reflectance values were in the range of 4-6.5%, however the dependence on MWCNT concentration was not very significant. Excellent adhesion to the aluminum substrates was achieved, for coatings with CNT concentration below 15%, while still having very low reflectance, even at temperature cycling between 200. °C and -. 196. °C. The proposed coating formulations enable simple and low cost approach for producing high light-absorbing coating of complex 3D structures within a very short time by wet deposition of CNTs.
Bibliographical noteFunding Information:
This research was partly conducted within NTU-HUJI-BGU Nanomaterials for Energy and Water Management Program under the Campus for Research Excellence and Technological Enterprise (CREATE), that is supported by the National Research Foundation, Prime Minister's Office, Singapore , and by the Israel Ministry of Trade and Industry under its NES Magnet program.
© 2014 Elsevier B.V.
- Carbon nanotubes
- Spray coating
- Stray light reduction
- Super-black coating