Pechmann Dye-Containing Diketopyrrolopyrrole-Based Stretchable Polymer Semiconductors

Conjugated polymer design via random terpolymerization with irregular backbones has emerged as a strategy for stretchable organic electronics, requiring diverse molecular architectures to balance charge carrier mobility (μ) and stretchability. In this study, diketopyrrolopyrrole (DPP)-based conjugated polymers with 0%, 5%, and 10% Pechmann dye (PDy) units, denoted as DP-T0, DP-T5, and DP-T10, respectively, are introduced, and explore the impact of PDy on structural mobility and stretchability through experimental and computational analyses. Electrical measurements reveal hole mobilities ranging from 0.01 to 0.08 cm² V⁻¹ s⁻¹, with a slight decrease as PDy content increases. Stretchability tests indicate significant improvements in DP-T5 and DP-T10 due to their loosely packed lamellar structures. Notably, DP-T5 achieves a crack onset strain (ε_c) of 250% and a polarization dichroic ratio (PDR) of 2.4 under 200% strain, leading to a mobility ratio (μ₂₀₀/μ₀) exceeding 5. These results demonstrate that PDy incorporation enhances the mechanical stretchability of DPP-based conjugated polymers while maintaining reasonable electronic performance. This work highlights the potential of PDy-based random terpolymerization for developing stretchable polymer semiconductors.