Supplementary materials
Stability enhancement of an electrically tunable colloidal photonic
crystal using modified electrodes with a large electrochemical potential
HongShik Shim, 1,2 Chang Gyun Shin, 1 Chul-Joon Heo,1 Seog-Jin Jeon, 1 Haishun Jin, 1 Jung
Woo Kim,1 YongWan Jin,1 SangYoon Lee, 1 Joohyun Lim, 2 Moon Gyu Han, 1,* and Jin-Kyu Lee
2,*
1
Samsung Advanced Institute of Technology, Yongin-Si, Gyeonggi-do, Republic of Korea
2
Department of Chemistry, Seoul National University, Seoul, Republic of Korea
Corresponding Author
*E-mail: moongyu.han@samsung.com and jinklee@snu.ac.kr.
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S1. Schematic diagram of reflective color tuning of an electrically tunable colloidal
photonic crystal
Glass
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S2. Detailed simulation parameters and equations for ion concentration and diffusion in
electrically tunable colloidal photonic crystal cell.
The followings are more detail information of our simulation. We have used basic
electrochemical formulas as described below;
[Governing equations]
(mass balance)
∂c𝑖
+ ∇ ∙ (−𝐷𝑖 ∇𝐶𝑖 − 𝑧𝑖 𝑢𝑚,𝑖 𝐹𝑐𝑖 ∇V) = 0
∂𝑡
(Current balance)
∇ ∙ (−σ∇V) = 0
(Butler-Volmer equation)
𝛼𝑎 𝐹 𝜂
𝛼𝑐 𝐹 𝜂
𝑖 = 𝑖0 [exp (
) − exp (
)]
𝑅𝑇
𝑅𝑇
(Overpotential)
𝜂 = 𝑉𝑒𝑥𝑡 − 𝑉 − 𝐸𝑒𝑞
Where,
c𝑖 : Concentration of i species
𝐷𝑖 : Diffusion coefficient of i species
𝑧𝑖 : Charge number of ionic species
𝑢𝑚,𝑖 : Ionic mobility of i species
𝐹 : Faraday’s constant
𝑉 : Potential
𝑖 : Current density
𝑖0 : Exchange current density
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𝛼𝑎 : Anodic transfer coefficient
𝛼𝑐 : Cathodic transfer coefficient
𝜂 : Overpotential
𝑅 : Gas constant
𝑇 : Temperature
𝑉𝑒𝑥𝑡 : Input potential (applied potential)
𝐸𝑒𝑞 : Equilibrium potential
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S3. The hydrogen and hydroxide ion generation and diffusion phenomenon (simulation).
S3-1. Hydrogen ions (H+, Multimedia view)
Simulation results of hydrogen ions generation and diffusion behavior when a 3.2V peak-to-peak
triangle waveform voltage is applied from 1st to 10th switching cycles. (enhanced online)
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S3-2. Hydroxide ions (OH-, Multimedia view)
Simulation results of hydroxide ions generation and diffusion behavior when a 3.2V peak-topeak triangle waveform voltage is applied from 1st to 10th switching cycles. (enhanced online)
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