A Comparison of Photophysical Properties of A Chiral Perylene Monoimide with 3,4,9,10-Perylenetetracarboxylic Acid

The perylene chromophore with versatile substituents offers strong absorption in the visible region with high molar extinction coefficients. Moreover, they are capable of emitting light with high fluorescence quantum yields near unity. The four carbonyl groups present in the core structure facilitate ease of accepting electrons and therefore perylene dyes plays important role for dye sensitized solar cells. In this project, perylene -3,4,9,10 tetracarboxylic acid (PTCA) and perylene-3,4-dicarboxylic-9,10-(R)(+)1phenylethyl)-carboximide (R-CPMI) were synthesized and their photophysical properties were compared. The synthesized compounds were characterized by FT-IR spectroscopy and photophysical properties were studied by absorption and emission spectroscopy. All the synthesized dyes have very high molar absorptivities. The highest value is obtained for R-CPMI 114000 M−1 cm−1. PTCA and PDA absorption spectra indicate aggregation formation where dye-dye molecular interaction in PTCA is higher than PDA. Introducing a chiral substituent at one end of the PTCA breaks dye-dye molecular interaction in polar aprotic solvents. R-CPMI absorption spectrum in polar protic solvent display 9 nm blue shift due to hydrogen bonding. Keywords: Perylene diimide, perylene monoimide, perylene carboxylic acid monoimide, perylene tetracarboxylic acid