• Singh, Surya Prakash
• Islam, Ashraful
• Karim, Mohammad Rezaul
• Yanagida, Masatoshi
• Han, Liyuan

Abstract

<jats:p>Three alkyl-substituted<jats:italic>β</jats:italic>-diketonato-ruthenium(II)-polypyridyl sensitizers with different alkyl chain lengths, [Ru(tctpy)(tfpd)(NCS)] (<jats:bold>A1</jats:bold>), [Ru(tctpy)(tfdd)(NCS)] (<jats:bold>A2</jats:bold>), and [Ru(tctpy)(tfid)(NCS)] (<jats:bold>A3</jats:bold>), were designed and synthesized for dye-sensitized solar cells (DSCs) to investigate the effect of bulky alkyl chain substituents on the photovoltaic performances (where tctpy = 4,4′,4′′-tricarboxy-2,2′:;6′,2′′-terpyridine, tfpd =1,1,1-trifluoropentane-2,4-dione, tfdd = 1,1,1-trifluorodecane-2,4-dione, and tfid =1,1,1-trifluoroicosane-2,4-dione). These complexes exhibit a broad metal-to-ligand charge transfer absorption band over the whole visible range extending up to 950 nm. All complexes were examined in the presence and absence of the coadsorbent deoxycholic acid (DCA) in dye-bath solutions. These sensitizers, when anchored to nanocrystalline TiO<jats:sub>2</jats:sub>films, achieve efficient sensitization to TiO<jats:sub>2</jats:sub>electrodes. Under standard AM 1.5 sunlight, the complex<jats:bold>A3</jats:bold>containing long alkyl chain length of C<jats:sub>16</jats:sub>yielded a short-circuit photocurrent density of 18.0 mA/cm<jats:sup>2</jats:sup>, an open-circuit voltage of 0.64 V, and a fill factor of 0.66, corresponding to an overall conversion efficiency of 7.6% in the absence of DCA. The power conversion efficiency of<jats:bold>A1</jats:bold>sensitized DSCs was significantly increased upon the addition of DCA as compared to that in the absence of DCA. However, the photovoltaic performance of<jats:bold>A3</jats:bold>was not dependent on DCA at all, probably due to the inherent structural nature of the<jats:bold>A3</jats:bold>molecule.</jats:p>

Topics

• density
• differential scanning calorimetry
• additive manufacturing
• power conversion efficiency
• Ruthenium