Transparent Hybrid Opals with Unexpected Strong Resonance‐Enhanced Photothermal Energy Conversion. Issue 2 (30th November 2020)

• Record Type: Journal Article
• Authors: Cang, Yu; Lee, Jaejun; Wang, Zuyuan; Yan, Jiajun; Matyjaszewski, Krzysztof; Bockstaller, Michael R.; Fytas, George
• Is Part Of: Advanced materials. Volume 33:Issue 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-30
• Subjects: absorption enhancement -- particle brush systems -- photothermal energy conversion -- slow photon; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202004732
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Photothermal energy conversion is of fundamental importance to applications ranging from drug delivery to microfluidics and from ablation to fabrication. It typically originates from absorptive processes in materials that—when coupled with non‐radiative dissipative processes—allow the conversion of radiative energy into heat. Microstructure design provides versatile strategies for controlling light–matter interactions. In particular, the deliberate engineering of the band structure in photonic materials is known to be an effective approach to amplify absorption in materials. However, photonic amplification is generally tied to high optical contrast materials which limit the applicability of the concept to metamaterials such as microfabricated metal–air hybrids. This contribution describes the first observation of pronounced amplification of absorption in low contrast opals formed by the self‐assembly of polymer‐tethered particles. The dependence of the amplification factor on the length scale and degree of order of materials as well as the angle of incidence reveal that it is related to the slow photon effect. A remarkable amplification factor of 16 is shown to facilitate the rapid "melting" of opal films even in the absence of "visible" absorption. The results point to novel opportunities for tailoring light–matter interactions in hybrid materials that can benefit the manipulation and fabrication of functional materials. Abstract : Optical absorption, being absent in the pure polymer matrix and that with ordered particles, is remarkably amplified in self‐assembled polymer‐tethered (brush) particles comprising low‐contrast constituents. The amplification is shown to be caused by "photon slowdown" and to induce rapid "melting" of materials even in the absence of "visible" absorption.