Synthesis and Photovoltaic Properties of Simple Fluorene-Based Triphenylamine Metal-Free Organic Sensitizers for Dye-Sensitized Solar Cells

Abstract Two novel metal-free organic dyes, TM-a and TM-b derived from triphenylamine have been successfully synthesized and characterized. These D-π-A sensitizers feature triphenylamine as an electron donor, fluorene and thiophene as π-bridges, and 2-cyanoacrylic acid as both an acceptor and an anchor. This architecture allows a deeper insight into the effect of modification of the properties of D-π-A sensitizers, which is beneficial to improve their performance of in dye-sensitized solar cells (DSSCs). Both the TM-a and TM-b dyes displayed maximum absorption in the visible region at 457 and 454 nm, respectively. The DSSCs based on TM-a exhibited a superior photoelectric conversion efficiency, along with higher open-circuit voltage and short-circuit current (η 2.91%, VOC 657 mV, JSC 6.81 mA cm–2, and FF 0.65). These results indicate that the dye, with triphenylamine as an electron donor and fluorene as a π-linker, is a highly promising candidate for efficient DSSC applications.