Pt-Free Nanostructural Electrocatalysts for Dye-Sensitized Solar Cells

Autor: Yi-June Huang, 黃奕鈞
Rok vydání: 2019
Druh dokumentu: 學位論文 ; thesis
Popis: 107
This dissertation aimed to systematically study Pt-free and TCO-free counter electrodes (CEs) with low-costs and highly cell efficiencies (η’s). This dissertation is divided into two parts: (1) Pt-free CEs (Chapter 3 and Chapter 4) and (2) Pt-free and TCO-free CEs (Chapter 5 and Chapter 6). In the case of Pt-free CEs, we aim to reduce the costs of the DSSCs using various electro-catalysts for completely replacing the expensive Pt via the simple, non-vacuum, and low-cost fabrication processes. Accordingly, three types of Pt-free composite films were studied using a standard iodide electrolyte. (I) Transition metallic compound-type CEs, i.e. CoSe2/CoSeO3 with nanocube (NC), nanorod (NR), and nanoparticle (NP) structures in Chapter 3, the composite films of CoSe2/CoSeO3 with hierarchical urchin-like structure in Chapter 4, were indivitually investigated. In the composite film, the different nanostructures were separately used to provide attractive electro-catalytic abilities and large active areas for I3- reduction. (II) Transition metallic and conducting polymer type CEs, i.e. MoSe2 NS/PEDOT:PSS in Chapter 5, were investigated to provide large surface area, fast eletrolyte penetration, well adhesion, and rapid reaction rate for I3- reduction. (III) Carbonaceous-type CEs, i.e. pristine monolithic carbon aerogel (CA-O, CA-Q, CA-F, CA-C, and CA-G) in Chapter 6, were investigated by controlled resorcinol (R)/formaldehyde (F) and resorcinol (R)/sodium carbonate (C) molar ratios. In the case of Pt-free and TCO-free CEs. In the case of Pt-free and TCO-free CEs, the classic TCO substrate is replaced by Ti foil and carbon aerogel for low-cost, simple preparation process, and large-scale production. (I) Ti foil substrate collocate with MoSe2 NS/PEDOT:PSS, which presents a higher η of 8.51 ± 0.05%, as compared to a lower η of 8.21 ± 0.02% using the Pt-coated Ti foil CE. (II) Carbon aerogel replace traditional CEs based on the Pt/FTO/glass in DSSCs. The DSSCs using the as-prepared CA-C CE gave the best η of 9.08 ± 0.01%, among all the CA CEs. In brief, this dissertation explores three Pt-free composite films of CoSe2/CoSeO3, MoSe2 NS/PEDOT:PSS, and CA are a promising substitutions of Pt due to their outstanding properties, i.e., good electro-catalytic ability for I3– reduction, low-cost, simple preparation process, and easy for large-scale production.
Databáze: Networked Digital Library of Theses & Dissertations
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