Highly flexible honeycomb-structured flexible transparent conductive electrodes by inkjet printing for light-emitting devices

Abstract

The incorporation of flexible transparent conductive electrodes as the core of flexible light-emitting devices expands the potential application scenarios of wearable devices, due to their bendable characteristics. The three principal criteria for transparent, flexible conductive electrodes are high light transmittance, low sheet resistance and high bending resistance. This paper presents the design and preparation of a honeycomb-structured flexible transparent conductive electrode (H-FTCE) based on inkjet printing technology. The honeycomb-structured electrodes on the substrate were subsequently transferred to the PMMA substrate using aqueous sacrificial layer transfer technology. The sheet resistance value (11.27 Ω sq⁻¹) and the average transmittance in the visible region (86.44%) of H-FTCEs are comparable to those of the commercial ITO-PET substrates. Furthermore, after 70 000 bending tests (with a bending radius of 5 mm), the resistance value of the H-FTCEs exhibited an increase of 5.53% relative to the initial state, which is considerably lower than that of the commercial ITO-PET substrates. The organic light-emitting devices prepared with H-FTCEs demonstrated minimal brightness decay, with a maximum of 1%, following 500 bending tests at a driving voltage of 7 V. The research in this paper provides ideas for the application of H-FTCE design in flexible optoelectronic devices.