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Proceedings Paper

Colorimetric humidity sensors with sub-50ms response times using randomly arranged titania microspheres (Conference Presentation)

Paper Abstract

Disordered photonic systems as observed in iridescent insects and flowers introduces new pathways for realizing cost-effective and scalable structural colors. In this work, we present a fast-colorimetric humidity sensor derived from a disordered arrangement of polydisperse nanoporous titania microspheres. The sensor relies on changes in the total scattering of the microspheres upon variations in the surrounding humidity. The incoherent scattering from each particle allows the sum of the individual cross sections to determine the total scattering cross section, which converts the individual noisy spectra to a smoothly varying spectrum that gives rise to a saturated color.[1] We show that because the titania microspheres is highly porous with 1~2 nm-sized nanopores, water can diffuse into the particle interior via intracrystalline dynamics, thereby changing the effective permittivity and consequently the scattered color at ultra-fast speeds (sub 50ms). Our results provide a practical route toward achieving cheap, simple, scalable, ultrafast colorimetric humidity sensors using structural colors from disordered nanoporous microspheres [2]. [1] Alam, A-M; Baek K; Son J; Pei Y-R; Kim D-H; Choy J-H; and Hyun J-K. Generating Color from Polydisperse, Near Micron-Sized TiO2 Particles, ACS Appl. Mater. Interfaces, 2017, 9 (28), 23941– 23948 [2] M-Noor, S; Jang, H ; Baek K; Pei Y-R; Alam, A-M; Kim,Y.H; Kim, I.S; Choy, J.H and Hyun J-K. Ultrafast humidity-responsive structural colors from disordered nanoporous titania microspheres. Submitted (2019)

Paper Details

Date Published: 10 September 2019
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Proc. SPIE 11089, Nanoengineering: Fabrication, Properties, Optics, Thin Films, and Devices XVI, 110891D (10 September 2019);
Show Author Affiliations
Syazwani Mohd Noor, Ewha Womans Univ. (Korea, Republic of)
Hansol Jang, Ewha Womans Univ. (Korea, Republic of)
Kyungnae Baek, Ewha Womans Univ. (Korea, Republic of)
Yi-Rong Pei, Ewha Womans Univ. (Korea, Republic of)
Al-Mahmnur Alam, Ewha Womans Univ. (Korea, Republic of)
Jin-Ho Choy, Ewha Womans Univ. (Korea, Republic of)
Jerome K. Hyun, Ewha Womans Univ. (Korea, Republic of)


Published in SPIE Proceedings Vol. 11089:
Nanoengineering: Fabrication, Properties, Optics, Thin Films, and Devices XVI
Balaji Panchapakesan; André-Jean Attias, Editor(s)

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