Low‐Heat‐Driven Intrinsic and Fast Self‐Healing Photoelectronic Films Based on All‐Organic PEDOT:PSS Composite Adjustment

Abstract

Film electronic materials capable of bionic self‐healing have urgent research value in view of the widespread need of extending device life, maintaining operation safety, and reducing renewal costs. Thermal‐driven self‐healing is a dominant strategy to fit the practical film applications of one of the most famous solution‐processible conducting polymers (CPs), poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). Here, disulfide bonding embedded thermoplastic polyurethane (PU‐SS) was developed to endow their composites with PEDOT:PSS with great aqueous system compatibility, stability, film formation capability as well as recyclable capability, with help of triethylamine (TEA)‐assisted pH control (6.5 ± 1.0 at 25°C, weakening the adverse effects of strong acidity of PEDOT:PSS aqueous system itself). The scratched PEDOT:PSS(TEA)/PU‐SS films (10.121 ~ 7.629 μm cracks) under optimized the ingredient proportion exhibited excellent synergistic self‐healing capability of morphology and electrical properties (approximately 1.35 × 10−4 S/cm) even under spin‐coated thickness (20 ± 10 μm) and 25°C within 10 min. Drop‐coated flexible film (120 ± 20 μm thickness) showed high tensile strength with above 400% stretched length compared to that of PEDOT:PSS film (< 10%). Excellent water‐resistance (immersing > 7 days), strengthened substrate adhesion and electrochromic behavior (from light blue [−1.3 V] to white [1.2 V]) were realized. These comprehensive features can be reproduced for recyclable films on the basis of isopropanol (IPA) redispersion. Flexible electrochromic devices employing such film as the active layer exhibited high optical contrast (ΔT) values up to 52.07%, fast response time (2.10/3.70 s), as well as excellent coloring efficiency (198.02 cm2 C−1) and cycling stability. This research is expected to promote the promising applications of PEDOT:PSS based electronic materials from traditional fields to flexible or stretchable devices and even hydrogel bioelectronics.