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Liquid Phase Preparation of Hybrid Materials Based on Copper (Ⅰ) and 7,7,8,8-Tetracyanoquinodimethan (TCNQ)

Author: ChenYao
Tutor: YangHui
School: Zhejiang University
Course:
Keywords: copper(I) perovskite reduce electrodeposition lead TCNQ spontaneous corrosion
CLC: O621.258
Type: Master's thesis
Year: 2010
Downloads: 36
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Abstract

These works are mainly focus on how to improve the conductivity of two kinds of organic-inorganic hybrid crystals. One is in the perovskite structure and the other contain stacks of planar, partially oxidized (or reduced)π-πconjugated molecules.The perovskite structure has a lot of physical properties and the famous is the high temperature superconductivity. Following this idea, we made an effort to reduce the Cu2+ in the (C4H9NH3)2CuCl4 crystal which we have prepared in previous works and keep its structure still. We believe the new crystal will show good conductivity like being doped. I chose various ruductants, and also tuned the turn of adding them in. Finally, I determined the structure and component of the crystal by Fourier transformation infrared spectrum, uv-vis spectrum, powder X-ray diffraction.The other crystal, metal-tetracyano-p-quinodimethane (TCNQ) salt, is also an important charge transfer complex, its analogues have a great range of electrical and optical properties. TCNQ plays the role as electron acceptor, the stacks of planar, partially oxidized (or reduced)π-πconjugated molecules provide a tunnel for the electrons. The metal ion donates an electron and becomes the coordinating centre which makes the TCNQ molecules more regulating. In order to change the coordinating state of TCNQ molecules including the amount of TCNQ molecules involved, the distance of the molecular centroids and the relative sites, we can change the metal ion, applied an external field or the condition of reacting. I synthesized the Pb(TCNQ)2·nH2O polycrystalline film on lead foil and ITO with lead depositing substrate by spontaneous corrosion and characterized the specimen by Fourier transformation infrared spectrum, uv-vis spectrum, powder X-ray diffraction. I found that water played an important role during the formation of the Pb(TCNQ)2·nH2O polycrystalline film. To confirm it, I monitored the potential of the working electrode when the spontaneous corrosion were occurring and found the potential of the working electrode shifted towards positive which means making the corrosion much easier, the effective time of film formation equals to the potential of the working electrode achieved the steady state, water will accelerate the process. There is another try on electrodepositing the Pb(TCNQ)2-nH2O polycrystalline film on ITO substrate directly. The film is also characterized by Fourier transformation infrared spectrum, uv-vis spectrum, powder X-ray diffraction, thermoanalysis. Unfortunately, this try failed. I try to explain it according the Frank-Condon principle: the energy level between the TCNQ radical anion and the Pb2+ is too large to overcome.

Liquid Phase Preparation of Hybrid Materials Based on Copper (Ⅰ) and 7,7,8,8-Tetracyanoquinodimethan (TCNQ)

Abstract

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