IPMCs Incorporating ZnO Thin Film

ZnO is a widely used functional material due to its rniique optical and piezoelectric properties. It has wide band gap ( 3.37eV), good electrical conductivity ( 5 x lO fl cm ), and piezoelectric property. Incorporating the ZnO film onto IPMC electrodes was studied in a view of developing IPMC for optical applications [Kim et al. (2009)]. Namely, piezoelectric properties of ZnO are potentially able to convert mechanical energy into electrical energy, and in conjunction with the optical properties of the material, the IPMCs coated with thin ZnO film can be of interest for opto-electrical applications. 

Zinc nitrate (Zn(N03)2) and dimethylamine borane (DMAB) with a reagent grade from Sigma-Aldrich were used to synthesize the thin film of ZnO on the Pt-IPMC electrodes. The chemical deposition method was used because the conventional methods such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and DC or RF sputtering require temperatures from 200 °C to 800 °C, while IPMC could not withstand such high temperatures. ZnO thin films were synthesized on the Pt IPMC in an aqueous solution composed of 0.1 mol/L zinc nitrate hydrous and 0.1 mol/L DMAB maintained at 60 °C. As the electrical and optical properties of ZnO film depend on the DMBA concentration. ZnO film prepared from the 0.1 mol/L DMAB solution showed the best results. The optimum deposition condition for ZnO as reported in [Izaki and Katayama (2000)] was used. 

SEM microscopy was used to investigate the shape and grain sizes of ZnO films. The composition of the ZnO/Pt electrode was characterized in 

The opto-electrical property of the ZnO/Pt IPMC was characterized using photoluminescence (PL). In order to understand the PL quenching phenomenon, measurements of the PL spectrum as a function of the potential were carried out with potential variation of 0-2.0 V. Fig 3.14 (a) shows the variation of PL spectra of the ZnO/PT IPMC recorded at the room temperature using an excitation wavelength of 280 nm. The spectra of the sample displays a broad emission band with some vibronic structure from 350 to 500 nm and the maximum emission wavelength is Xmax = 468 nm. The blue emission is believed to originate from intrinsic defects, particularly interstitial zinc [Fang et al. (2004)]. The maximum PL intensity is observed 

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