Solid-state structure and optical properties of highly fluorescent diketopyrrolopyrrole derivatives synthesized by cross-coupling reaction

Diketopyrrolopyrrole (DPP) derivatives with four different substituents were synthesized by cross-coupling reactions. The DPP derivatives were investigated in terms of their solid-state structure, absorption, emission, and electrochemistry. The electron-donating property of each substituent causes a redshift of UV/vis absorption and emission in the solution state. Although all of the DPP derivatives have high quantum yields in solution, only butoxyphenyl-substituted DPP exhibits strong emission in the solid state