Chiral Diketopyrrolopyrrole Thin Films: Unlocking Circularly Polarized Light for Next-Gen Optoelectronics

We report the synthesis and characterization of the two enantiomeric forms—(R)- and (S)-configured—of a chiral thienyl-substituted diketopyrrolopyrrole (DPP) derivatives functionalized with optically active alkyl side chains. The introduction of chirality into the molecular framework enables the exploration of its chiroptical properties and potential applications in emerging optoelectronic technologies.

Thin films of both enantiomers were fabricated using two different deposition techniques: spin coating and drop casting. These methods were selected to evaluate the influence of film morphology and molecular organization on the optical and chiroptical responses. Comprehensive spectroscopic characterization was conducted, including UV–Vis absorption, circular dichroism (CD), and circularly polarized luminescence (CPL) measurements.

The CD and CPL spectra revealed clear signatures of opposite chirality for the two enantiomers, confirming the successful transfer of molecular chirality into the solid-state films. Notably, distinct differences in spectral features were observed between the films prepared by spin coating and those obtained via drop casting, indicating the crucial role of processing conditions in modulating chiroptical performance.

Furthermore, preliminary device fabrication was carried out to assess the potential of these chiral DPP-based materials in practical applications. The initial results are promising and suggest that this class of compounds may serve as suitable candidates for use in chiral photodetectors or circularly polarized organic light-emitting diodes (CP-OLEDs).