Facile and Large-Area Preparation of Polypyrrole Film for Low-Haze Transparent Supercapacitors.

The transparent flexible supercapacitor is considered to be the key energy-storage component for the development of wearable and fully transparent electronic devices. However, the current transparent supercapacitor faces the low-haze challenge, which is essential for the high-definition visualization in transparent electronics. Herein, we developed a facile interfacial polymerization approach for the large-area preparation of flexible polypyrrole/polyethylene terephthalate (PPy/PET) transparent conductive films in a cost-effective way. The PPy/PET film exhibits a highly uniform morphology and a low haze level of 1.40% (corresponding to high definition) as well as negligible resistance changing under an ultrasmall bending radius. The sandwich-structured, large-area, transparent supercapacitor assembled based on the PPy/PET films also keeps a similar low haze level. A facile N, N-dimethylformamide etchant-written strategy on the PPy/PET film is developed to fabricate the patterned micro-supercapacitors (MSCs) in series in scalable area, which show a low haze level of 1.66% and a high transparency of 70.2%. Significantly, the low-haze MSC possesses high energy-storage capacity and presents almost no capacitance loss at an extreme bending state. This work demonstrates a facile preparation of large-area and low-haze transparent flexible supercapacitors and also enlightens broad interests in their potential integrity toward the fully transparent wearable electronics.