In spite of efforts to fabricate stimuli-sensitive structural colors (SCs) of self-assembled block copolymer (BCP) photonic crystals (PCs) with potential applications in displays, media boards, and sensors, few studies have demonstrated BCP PCs suitable for high-density nonvolatile information storage. Herein, a simple but robust route for multilevel nonvolatile information recording using a BCP PC is presented. The proposed method is based on the spatially controlled crosslinking of microdomains of a BCP PC induced by photothermal conversion. Photothermal SC writing is accomplished via time- and position-controlled laser exposure on thin poly(styrene-block-quaternized 2-vinyl pyridine) (PS-b-QP2VP) PC films deposited on a layer of poly(3,4-ethylenedioxythiophene) doped with tosylate (PP-PEDOT). Upon near-infrared (NIR) irradiation of this structure, the PP-PEDOT underlayer converts the NIR light into thermal energy in the locally irradiated region, which is subsequently transferred to the BCP top layer consisting of alternating in-plane PS and QP2VP lamellar stacks. The QP2VP layers are vulnerable to thermal crosslinking, giving rise to locally programmable SCs. The degree of crosslinking of the QP2VP domains depends on the laser power and exposure time, which allows for multi-SC recording per spot, leading to a novel multilevel optical recording medium based on BCP PCs.
Bibliographical noteFunding Information:
H.E. and H.S.K. contributed equally to this work. This research was supported by the Samsung Research Funding Center of Samsung Electronics under Project No. SRFC-MA1301-03. This research was also supported by a grant from the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2017R1A2A1A05001160). H.E. and H.S.K. conducted most of the experiments, including the fabrication of devices and analysis of data, and prepared the manuscript. M.K., M.J.K., T.H.P., and J.H. contributed to the measurement and analysis of the optical properties of the BCP SC film. Y.K. and D.Y.R. synthesized the BCPs, and H.L. and E.K. fabricated the photothermal-conversion layer. C.P. and Y.K. supervised the project, analyzed the data. All authors discussed the results and contributed to the paper.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics