Low-aggregated multi-color perylene diimide derivatives and their photo-thermal stability in color films

Abstract

Perylene diimide derivatives (PDIs) have potential applications in organic semiconductor devices owing to their high absorption coefficients and chemical persistency. However, molecular aggregation and inferior thermal stability limit their preparation and application as color-film devices. In addressing this issue, we designed a series of PDIs by introducing different steric hindrance group (propyl isobutyl polyhedral oligomeric silsesquioxane (propyl isobutyl POSS), isoctyl, and 2-octyldodecyl) at the terminal position and electron-donating group (alkoxy, alkyl-substituted phenoxy or alkylamino) at the bay position. Density Functional Theory (DFT) calculations demonstrated that the substitution of propyl isobutyl POSS at the terminal position and electron-donating groups (2,4-di-tert-butylphenoxy, tert-butyloxy, and diethylamino) at bay position of the perylene chromophore had synergistic effect on reducing the aggregation of PDIs, and the bay substitution could achieve PDIs with different colors due to the connection of the substituent group with the conjugated system of the PDIs. Based on the results of calculation, four low-aggregated multi-color PDIs were synthesized for the first time. Their color films displayed excellent photo-thermal stability because of the introduction of propyl isobutyl POSS moieties (Td > 230 °C, color difference ΔE < 3). This work provides important insights into the design of multi-color PDIs with low aggregation and high photo-thermal stabilities, which holds great promise for the organic electronics research field.