Strong adhesion and high optoelectronic performance hybrid graphene/carbon nanotubes transparent conductive films for green-light OLED devices

Carbon nanotubes (CNTs) and graphene (Gr) are promising materials for flexible transparent conductive films (TCFs) in optoelectronic application because of their exceptional electrical, optical, and mechanical properties. Here, high-quality graphene nanosheets were synthesized by the one-step green method which using natural polyphenols-gallic acid (GA) as the exfoliation medium through high-pressure homogenization; besides, GA molecules can also be used as a non-covalent modifier to obtain GA modified CNTs (GCNTs). Then, the Au decorated Gr/GCNT-PET (Au-Gr/GCNT-PET) TCFs were obtained by a simple spray-coating process. The TCFs exhibited an excellent optoelectronic performance (Rs = 45.6 Ω/sq., T = ca. 80% at 550 nm), relatively flat surface (roughness = 12.43 nm), good bending resistance (the ΔR Au-Gr/GCNT-PET TCF/R0 was 0.07 after 1000 times bending tests) and strong adhesion (the fT of all Au-Gr/GCNT PET films was higher than 0.8). Finally, the Au-Gr/GCNT-PET films were used as an anode to prepare flexible green-light OLED devices; the maximum luminance of the Au-Gr/GCNT-PET device was 6554.1 cd/m2 at 15V, and the maximum current efficiency was 4.03 cd/A. It confirmed that this type of TCFs has considerable potential application in photovoltaic devices.