Article ID Journal Published Year Pages File Type
6598044 Dyes and Pigments 2018 45 Pages PDF
Abstract
Molecular engineering toward decreasing the band gap and thus extending the absorption spectrum of benzotriazole-based dye is a challenge. Herein, the benzotriazole structure is finely tuned by fusing another electron deficient ring to the benzo unit leading to a series of benzotriazole-based electron-withdrawing heterocyclic rings including benzobitriazole, benzotriazolequinoxaline and benzotriazolethiadiazole. These together with benzotriazole are incorporated into the π-bridge, respectively, as an auxiliary acceptor between the triphenylamine donor and the cyanoacrylic acid anchoring group for the construction of donor-auxiliary acceptor-π-acceptor type sensitizers (LC-2, LC-3, LC-4 and LC-5). The benzobitriazole, benzotriazolequinoxaline and benzotriazolethiadiazole units show greatly increased electron-withdrawing capability and the corresponding sensitizers (LC-3, LC-4 and LC-5) exhibit broadened spectral response range compared to the reference benzotriazole-based dye LC-2 due to the decreased energy gap. Thus, the LC-3 and LC-4 cells exhibit significantly enhanced photocurrent density (Jsc) values due to the greater light-harvesting abilities compared to LC-2. However, the electrochemical impedance analysis suggests the electron lifetime and charge recombination resistance are decreased due to the introduction of benzobitriazole, benzotriazolequinoxaline and benzotriazolethiadiazole, resulting in a slight loss of open-circuit voltage (Voc). The findings provide a guidance for the future molecular design of highly efficient organic sensitizers for use in dye-sensitized solar cells.
Related Topics
Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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