Special Articles on Organic and Inorganic Optical Materials. Relation between Molecular Structures of Dyes and Photovoltaic Properties in Tow-Layer Organic Solar Cells Using Phthalocyanines and Perylenetetracarboxylic Acid Derivatives.

Design of Near-Infrared Dyes Based on π-Conjugation System Extension. Theoretical Evaluation of Arylimidazole Derivatives of Perylene Chromophore

“…e R = 1-hexylheptyl, in CHCl 3 solution, ref . f tert -Butyl-substituted benzimidazole, cis−trans mixture, in DMF solution, ref a.…”

“…The chromophoric system of PTCAI 1 is a symmetrical rigid structure, therefore, only a few vibronic bands have the pronounced intensity. On the other hand, the arylimidazoles introduction causes the absorption spectral broadening. − A dull spectrum shape is generally undesirable, because some practical applications, e.g., dye lasers, optical filters, optical-disks, and so on, strictly require the spectral sharpness of materials. The molecule symmetry is lowered by the arylimidazoles introduction, as a result, many vibronic bands should have intensity and the spectrum shape becomes broad…”

“…The orbital interaction between HOMOs of the perylene and the aryl group at the substituted point causes the bathochromic shift, in other words, their absorption properties can be looked upon as the perturbed perylene system. Moreover, many kinds of arylimidazole-introduced dyes have been evaluated their absorption properties (see section 3.D, Table , and refs −9), but none of the dyes absorb NIR light…”

“…It has been generally accepted that an increase in the size of the π-conjugation causes a shift toward a longer absorption wavelength (bathochromic shift) . To design the NIR dyes, there are two ways of the PTCAI π-conjugation system extension: an arylimidazole introduction − and a perylene framework extension . In this paper, we theoretically analyze the absorption spectrum shift by using the semiempirical MO INDO/S method, focusing on the arylimidazole introduction.…”

“…Many types of arylimidazole-introduced PTCAIs have been synthesized and reported their properties and applications, but solubility of these molecules is generally low. As a result, their absorption spectra have not been clearly elucidated and details of the absorption spectrum shift have not been characterized.…”