Pyrrolo[3,2,1-kl]phenothiazine-based D-π-A type organic dyes for efficient dye-sensitized solar cells

Abstract

Novel metal-free organic dyes based on polycyclic aromatic donor, pyrrolo[3,2,1-kl]phenothiazine, have been synthesized and applied in dye-sensitized solar cells. Combined with cyanoacrylic acid as the acceptor/anchoring group and simple π-spacers such as thiophene (JY40), furan (JY41), and terthiophene (JY42) as the conjugated linker, these dyes show good power conversion efficiency (PCE). The photophysical, electrochemical and photovoltaic properties, as well as theoretical calculations of these dyes were fully investigated. An attractive PCE up to 7.54%, with a short-circuit photocurrent density (Jsc) of 17.76 mA cm−2, an open-circuit photovoltage (Voc) of 726 mV, and a fill factor (FF) of 0.58 has been achieved by the JY42-based cell under standard AM 1.5 G irradiation in conjunction with an iodine electrolyte.