Investigation Of Preparation And Photo-Current-Voltage Characteristics Of Phthalocyanine-Sensitized Nanostructured TiO₂ Electrodes

Dye-sensitized nanocrystalline solar cell(DSSC) with a conversion up to 10% has become the most promising alternative to the conventional silicon solar cell .It is a new photovoltaic device with low cost, simple processes, stability, extensive application and little weight. In this thesis, we prepared phthalocyanine complexes sensitized nanocrystalline TiO₂ film electrode by self-assembling and electrochemical-depositing , and also studied the photoelectric characterization of these electrodes.1 The SEM of the TiO₂ film prepared by anodic oxidation hydrolysis showed that the surface of the films was close-packed, homogeneous ,UV-vis spectrum showed that the light transmittivity was more than 90%, which fulfills experiment requirement. The TiO₂ sol solution, the paste for the electrode, was prepared by the sol-gel method .The SEM of the TiO₂ film screen-printed on the ITO showed that the film was porous , high surface roughness, suitable for the electrode of DSSC. The photocurrent result showed that the close-packed TiO₂ film can improve the performance of the solar cell.2 The MPc(COOH)4(M= Co, Ni,Cu,Zn) sensitized TiO₂ film was prepared by self-assembled . The I-V curves are similar in the solution of DMF and DMSO.The photocharacteristic of the electrode preparated in DMF was better than DMSO.The ZnPc(COOH)4 sensitized electrode is better than others, CuPc(COOH)4 takes second place.The principle of sensitized electrode that was concluded from the photocurrent-photovoltage characteristics of the MPc(COOH)4(M= Co, Ni,Cu,Zn) compounds was Co﹤Ni﹤Cu﹤Zn。3 The MPc(NH₂)₄(M= Co, Ni,Cu,Zn) sensitized TiO₂ film was prepared by self-assembled. In the solution of DMF and DMSO CuPc(NH₂)₄ is better than others, ZnPc(NH₂)₄ at the latest.The Isc of CoPc(NH₂)₄ was higher than NiPc(NH₂)₄,and the Vsc of NiPc(NH₂)₄ was higher than CoPc(NH₂)₄,and the photocharacteristic was no difference between DMF and DMSO. Because lack of group such as -SO3H,-COOH, the dye only absorb on the surface of TiO₂ or depend on the hydrogen bond ,and the long distance reduces the probability of the tunneling effect of photoelectron.The principle of sensitized electrode that was concluded from the photocurrent-photovoltage characteristics by the MPc(NH₂)₄(M= Co, Ni,Cu,Zn) compounds was Zn﹤Ni﹤Co﹤Cu。4. The effect of the TiO₂ film thickness on the solar cell performance was primarily study . The influence of the thickness on the open circuit voltage, short circuit current, fill factor and photoelectron conversion efficiency was investigated.5. The cyclic voltammograms of MPc(NH₂)₄ in dimethylformamide (DMF) on such TiO₂ film electrode was studied and the oxidation-reduction potentials of MPc(NH₂)₄ were investigated . concluding that in the CV curve of CoPc(NH₂)₄ on the TiO₂ film electrode two pairs of oxidation-reduction peaks can be assigned to the Co3+/Co2+,Co2+/Co+,and three oxidation-reduction peaks can be assigned to the Pc ring. in the CV curve of NiPc(NH₂)₄ on the TiO₂ film electrode two pairs of oxidation-reduction peaks can be assigned to the Ni3+/Ni2+,Ni2+/Ni+,and two oxidation-reduction peaks can be assigned to the Pc ring. in the CV curve of CuPc(NH₂)₄ on the TiO₂ film electrode one pairs of oxidation-reduction peaks can be assigned to the Cu2+/Cu+,and two oxidation-reduction peaks can be assigned to the Pc ring. in the CV curve of ZnPc(NH₂)₄ on the TiO₂ film electrode four pairs of oxidation-reduction peaks can be assigned to the Pc ring, and there is no oxidation-reduction peak of the center ion.6.MPc(NH₂)₄(M= Co,Ni,Cu,Zn) sensitized nanostructured TiO₂ electrode were prepared by potentionstatic-deposition. The performance of the electrode prepared by electrodepositing are much better than that by self-assembling. The principle of sensitized electrode by electrochemical-deposition that was concluded from the photocurrent-photovoltage characteristics by the MPc(NH₂)₄(M= Co, Ni,Cu,Zn) compounds was Zn﹤Cu﹤Co﹤Ni。Comparing with the electrode prepared by self-assembling, the open circuit voltage of NiPc(NH₂)₄...