Strain-Induced Detectivity Enhancement in Intrinsically Stretchable Organic Photodetectors.

Abstract

Intrinsically stretchable organic photodetectors (IS-OPDs) are essential for next-generation wearable electronics requiring both mechanical durability and reliable optical sensing. However, current performance of IS-OPDs degrades under tensile strain due to inherent trade-offs between mechanical and optoelectronic properties in photoactive layers. Here, we report the development of the IS-OPD that exhibits strain-induced detectivity (D) enhancement, enabled by designing mechanically robust and efficient bilayer-type photoactive architecture (EBL-D). Specifically, we incorporate percolated polymer donor (P_D):elastomer networks at the bottom layer, which simultaneously offer excellent stretchability and efficient charge transport. Subsequently, we deposit a small-molecule acceptor layer atop the P_D:elastomer layer, expanding the optical absorption range into the near-infrared region while minimizing undesirable charge recombination. The resulting IS-OPD based on the EBL-D architecture maintains high responsivity and effectively suppresses dark current under strain. Consequently, the device exhibits 1.5-fold improvement in specific detectivity from 1.9 × 10¹³ to 2.8 × 10¹³ Jones at λ = 860 nm under 75% strain, corresponding to a 1.3-fold increase in D after accounting for the enlarged photoactive area. To the best of our knowledge, this work is the first to experimentally demonstrate strain-induced D enhancement in stretchable OPDs.