旭硝子財団助成研究成果報告2020

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97Priastuti WulandariGrandprix Thomryes Marth Kadja98Photocurrent Enhancement by Localized Surface Plasmon Resonance of Gold and Silver Nanoparticles Functionalized by Organic Molecules in Dye Sensitized Solar Cells (Project 2019)Solvent-free, OSDA-free Synthesis of ZSM-5 Zeolites from Rice Husks: Towards a Sustainable Route (Project 2019)66旭硝子財団　助成研究成果報告（2020）second stage was carried out at a higher temperature (170 °C) for conducting crystal growth. For comparison, the sample was also prepared by means of One-Stage Temperature-Crystallization method (OSTC) at 170 °C. It was found that the samples synthesized by the TSTC method can give accelerated crystallization process with increasing aging time. As a result, MOR zeolite has morphology of rod-assembled leaf-like with the dominant growth direction of crystals along the c-axis. Analysis of particle size distribution shows that the crystals are homogeneous in the range of 4.5 to 7 µm. The characterization of zeolite samples were done by using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Infrared Spectroscopy (IR-ATR) and X-ray Fluroscence (XRF).Strong localized surface plasmon resonance (LSPR) field, which is generated from metal nanoparticles (gold and silver), may enhance photons absorption of dyes in dye-sensitized solar cells (DSSCs), resulting in the improvement of their power conversion efficiency (PCE). In this work, we attempt to incorporate gold or silver nanoparticles capped by organic molecules (citrate (AuCA), oleylamine (AuOA) and myristate (AgMy)) into the N-719 dye in DSSCs. We succesfully to synthesize gold and silver nanoparticles with several capping molecules and characterize by use of UV-Vis spectroscopy and Transmitance Electron Spectroscopy (TEM). While the cells were prepared by varying the weight percentage of metal nanoparticles with respect to the dye weight in dye solutions. In the case of dye solutions containing 1.4 wt%, 1.9 wt% and 2.4 wt% of AuOA exhibit enhancement in their absorption spectra in the UV-Visible range, which are assigned as the results from the excitation of localized SPR. The current density-voltage (J-V) characteristics of those DSSCs show enhancement in their photocurrent along with their power conversion efficiency (PCE) from 4.18% to 5.14% for the cells without incorporation of AuOA and with addition of 2.4 wt% of AuOA, respectively. This improvement is due to the enhancement of photons absorption and hence charge carrier generation by AuOA nanoparticles through the LSPR phenomenon. Green and sustainable research in zeolite synthesis has gained a lot of attention for several decades. efforts have been made from different aspects i.e. using sustainable raw materials, avoiding or reducing the use of OSDA (Organic Structure Directing Agent), and developing the facile method of synthesis. Herein we have successfully combined all of the aspects from the sustainable synthesis concept of zeolites. Highly crystalline ZSM-5 was obtained using silica rice husk in both OSDA- and solvent-free systems. The reactive silica was extracted through the sequential base-acid treatment. The result showed that pure ZSM-5 was observed at all temperatures. the crystallization of zeolite under the solvent-free method was studied using the Avrami equation. The different value of avrami’s exponents (n) was observed (n=2.4 at 180 and 200 °C, n=3.0 at 160 °C) indicated the different mechanism of crystallization at different temperature. Moreover, the different sizes and behavior morphology of crystal were observed for different temperatures. Based on the energy calculation, crystallization was more consumed energy during the nucleation process shown by the highest activation energy of En1 followed by En2 and Ec. Based on the result, this research provides the model to better understanding of the solvent-free, OSDA-free synthesis of zeolite. Moreover, this research may give feasible insight for achieving the ultimate goal of the sustainable synthesis of zeolite.