Strain-Tolerant, High-Detectivity, and Intrinsically Stretchable All-Polymer Photodiodes

A skin-like photodiode (PD) that is stretchable and skin-conformable is crucial to opening the next-generation wearable electronics for optical biometric monitoring, biomedical imaging, and others. To achieve reliable PD characteristics under large deformation, stretchable PDs with high detectivity and high mechanical stretchability must be developed. Herein, intrinsically stretchable polymer-based PDs (is-PPDs) comprising all-polymeric constituent layers are demonstrated. In particular, elastomeric photoactive layers consisting of an elastomer with p-/n-type semiconducting polymers and conducting polymer-based stretchable transparent electrodes with modulated work functions improve both the mechanical stability and the detectivity (D*) of is-PPDs. Accordingly, is-PPDs show excellent D* over 10(13) Jones with a suppressed dark current density of 0.1 nA cm(-2) before and after 100% stretching. The proposed is-PPDs record high-quality and stable photoplethysmography signals at the wrist with outward extension.

Automated summary

A stretchable and skin-conformable photodiode (PD) is essential for the development of next-generation wearable electronics. This study demonstrates intrinsically stretchable polymer-based PDs (is-PPDs) with high detectivity and high mechanical stretchability. By using elastomeric photoactive layers and conducting polymer-based stretchable transparent electrodes, is-PPDs exhibit excellent detectivity and stable performance even under large deformation.