Impact of anchoring groups for improving the binding nature of organic dyes toward high efficient dye sensitized solar cells

Abstract

A series of mono and bi-anchoring metal-free organic dyes containing diphenylamine or diethylamine as a donor which linked to the acrylic acid or nitro vinyl as acceptor through a phenyl π-spacer were synthesized through simple procedure and tested as photosensitizers for dye-sensitized solar cell applications. The synthesized dyes were well characterized by 1H, 13C NMR, mass spectrometry and elemental analysis. The optical, electrochemical, theoretical and photovoltaic properties of the synthesized dyes were investigated. Introduction of the additional electron acceptor unit leads to the significant improvement in the optoelectronic properties and DSSC performance. In general, bi anchoring dye based DSSCs show more than two times higher efficiency than the mono anchoring dye based DSSCs. Among the fabricated DSSCs, the carboxylic acid substituted bi anchoring dye (P2C) based DSSC show maximum power conversion efficiency of 3.86% under AM1.5 illumination (85mW/cm2). In order to confirm the need of more number of anchoring groups for improving the efficiency of solar cells, dye molecules with nitro derivatives were synthesized and the results were compared.