Synthesis And Properties Of Photovoltaic Material Based On Novel Zn(Ⅱ) Phthalocyanines

Solar energy is one of the largest and abundant renewable sources of energy inthis planet. But only a small part of it was used mainly due to the lack of effectiveapproach to harvest it. Among the approaches proposed to harvest solar energy,polymer bulk hetero-junction soalr cells (BHJ) and dye-sensitized solar cells (DSSCs)have become a research hotspot due to their low cost, easy to manufacturing and highefficiency. Phthalocyanines (Pcs), similar to porphyrins, being of large ring moleculeshave18π electrons and possess a strong absorption band in the red/near-infraredregion. Therefore, Pcs are very suitable to applicate in the field of photovoltaic cells.The main points that the research on phthalocyanine derivatives are to to broaden itsnarrow Soret-band, and simultaneously improve the poor solubility and amelioratethe weakness of easy accumulation, expecting of obtaining materials that could usedin solar cells and reaching high efficiency. In this thesis, on the basis ofphthalocyanine as the main direction, we designed and synthesized twophthalocyanine end-capped copolymers and organic dyes based on phthalocyaninethat was modified with thienyl or phenyl groups. All of which were applied in soalrcells. The structures of the intermediate products and the target products wereanalysised using a variety of methods. And the photophysical, electrochemical naturesof the copolymers and phthalocyanine dyes have also been discussed thorough. Thephotovoltaic performance of the solar cells corresponding to the two copolymersend-capped with phthalocyanines and phthalocyanine dyes were also analysised anddiscussed. The results are as follows:1. We synthesized two copolymers PHY1and PHY2, end-capped byphthalocyanie, containing thiophenes and benzothiadiazole (BTZ) moieties in the sidechain for bulk hetero-junction solar cells. Multiple physicchemical properties of thetwo copolymers, including thermalstabilities, photophysics, electrochemical, andphotoelectric performance, were investigated. The results elucidate that theintroduction of phthalocyanine moiety in the endings of the polymers could broadenand strengthen the absorption in the Soret-band and Q-band. We fabricated the bulkhetero-junction solar cells based on the copolymers blending with PC61BM in diffirentweight ratio, spin coating to form a film and evaporate plating the electrode. Underthe illumination of standard simulation of sun light, the maximum power conversionefficiency of1.56%(PHY1) and1.26%for (PHY2) were obtained. 2. Two novel phthalocyanine dyes (PC-HY1and PC-HY2) modified withtert-butylphenyl and tert-butylthiophene moieties were designed and synthesized via alow-cost “anhydride” method. It was found that the introduction of tert-butyl groupscould improve the solubility of phthalocyanines. The optical and electrochemicalproperties were conducted as well as polymers. From the study results we canconclude that with the introduction of thiophenes, the absorption spectra of the twophthalocyanine dyes were strengthened as well as broadened. Under standard globalAM1.5solar condition, small molecule hetero-junction solar cell using the dyePC-HY2exhibit better photovoltaic efficiency: a8.12mA·cm-2short-circuitphotocurrent density (JSC), an0.64V open-circuit photovoltage (VOC), and a0.30fillfactor (FF). And the relevant solar-to-electric power conversion efficiency (η) is1.56%. And the η of dye-sensitized solar cell based on PC-HY2(DSSC) was1.09%.