Prof. Jin-Ho Choy Profile

Prof. Jin-Ho Choy

at Ewha Womans Univ

SPIE Involvement:

Author | Editor

Publications (1)

Proceedings Article | 10 September 2019 Presentation

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

Syazwani Mohd Noor, Hansol Jang, Kyungnae Baek, Yi-Rong Pei, Al-Mahmnur Alam, Jin-Ho Choy, Jerome Hyun

Proceedings Volume 11089, 110891D (2019) https://doi.org/10.1117/12.2528696

KEYWORDS: Humidity, Sensors, Scattering, Particles, Ultrafast phenomena, Photonics systems, Titanium dioxide

Read 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)

Proceedings Volume Editor (1)

SPIE Conference Volume | 9 November 2012

Nanosystems in Engineering and Medicine

Conference Committee Involvement (2)

SPIE Nanosystems in Engineering + Medicine

10 September 2012 | Incheon, Korea, Republic of

Nanosystems in Engineering and Medicine

10 September 2012 | Incheon, Korea, Republic of

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