Aggregation of derivatives of benz[C, D]indole dyes: Effect of the side group and ambient temperatures

Two pairs of benz[c, d]indole dyes with the same chromophore in each pair have been studied in respect to their ability to form thin films through thermal evaporation in vacuum. Electronic absorption spectra of the films revealed that despite very slight variations in molecular structure different aggregate structures can be formed in the films. It has been shown that substitution of one carbon atom in the dye structure by a sulfur atom leads to crucial sensitivity of the aggregate structure to film thickness and substrate temperature. On the other hand, dye with bulky side groups was less sensitive to the changes in the deposition conditions.