New fluorenone-containing organic photosensitizers for dye-sensitized solar cells

• Published in: Dyes and pigments Vol. 98; no. 3; pp. 428 - 436
• Main Authors: Lai, Lai-Fan, Qin, Chuanjiang, Chui, Chung-Hin, Islam, Ashraful, Han, Liyuan, Ho, Cheuk-Lam, Wong, Wai-Yeung
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2013
• Subjects: Arylamine; Dye-sensitized solar cells; Fluorene; Fluorenone; Organic dye; Photosensitizer; Fluorene; Dye-sensitized solar cells; Organic dye; Arylamine; Photosensitizer; Fluorenone
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2013.03.007

Four new organic dyes (F1–F4) comprising the triarylamine or fluorene unit as an electron-donating group, a less commonly used fluorenone spacer and a cyanoacrylic acid as the anchoring group in the molecular framework were synthesized, characterized and utilized in dye-sensitized solar cells (DSSCs). Their absorption, photoluminescence, electrochemical and photovoltaic properties were fully investigated in detail. Electrochemical data indicate that the tuning of the HOMO and LUMO energy levels can be conveniently accomplished by alternating the donor moiety. The photovoltaic performance can be increased by adding an electron-donating triarylamine or fluorene unit next to the fluorenone ring or increasing the number of thienyl ring next to the cyanoacrylic acid group, which is consistent with the results from electrochemical impedance spectroscopy. The maximal monochromatic incident photon-to-current conversion efficiency (IPCE) can reach up to 80% for DSSC devices based on F4 with the overall light to electricity conversion efficiency up to 4.71% (Voc = 565 mV, Jsc = 11.71 mA cm−2 and FF = 0.71) under AM 1.5 irradiation (100 mW cm−2). A new family of fluorenone-based organic photosensitizers were described. The photovoltaic response can be enhanced by adding an electron-donating triarylamine or fluorene unit next to fluorenone or increasing the number of thienyl ring next to cyanoacrylic acid. These dyes showed the best power conversion efficiency of 4.71% in nanostructured dye-sensitized solar cells. [Display omitted] •We report fluorenone-containing organic sensitizers for dye-sensitized solar cells.•Effect of different electron donors on the photovoltaic performance was studied.•The maximal power conversion efficiency of 4.71% was achieved.