Organic sensitizers with different thiophene units as conjugated bridges: molecular engineering and photovoltaics

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• 作者：Wenqin Li ; Zihua Wu ; Jinmin Wang ; Weiwei Zhang ; Min Wu…
• 关键词：organic sensitizers ; conjugated bridge ; solar cells ; photovoltaic performances
• 刊名：Science China Chemistry
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：60
• 期：2
• 页码：231-236
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry/Food Science, general;
• 出版者：Science China Press
• ISSN：1869-1870
• 卷排序：60

文摘

Three structural modifications with incorporation of alkyl, alkoxy and vinyl bond into the skeleton of thiophene bridge in D-π-A featured organic sensitizers are specifically developed for insight into their influences on photophysical, electrochemical as well as photovoltaic properties in nanocrystalline TiO₂-based dye sensitized solar cells (DSSCs). The insertion of vinyl bond into the conjugation bridge leads to the molecular planar configuration, and the conjugation bridge of 3,4-ethylenedioxythiophene (EDOT) is prone to positively shift its highest occupied molecular orbital (HOMO). The electrochemical impedance spectroscopy (EIS) results indicate that the grafted long alkyl chain onto thiophene is favorable to suppress dye aggregation when adsorbed onto TiO₂ film and modification on interface of TiO₂/dye/electrolyte, resulting in a relatively high open-circuit voltage (V_oc). Under optimized conditions, dye LS-4 bearing hexylthiophene as the conjugation bridge shows a relatively high overall conversion efficiency of 5.45%, with a photocurrent of 11.61 mA cm–2, V_oc of 744 mV.