Large-Scale Flexible and Highly Conductive Carbon Transparent Electrodes via Roll-to-Roll Process and Its High Performance Lab-Scale Indium Tin Oxide-Free Polymer Solar Cells

A scalable and highly conductive PEDOT:PSS:CNTs transparent electrode (TE) is demonstrated for high performance optoelectronics. The aligned and uniform dispersion of electron conduction favored CNTs in the PEDOT:PSS matrix can achieve the rearrangement of the PEDOT chains with more expended conformation via the π–π interaction between CNTs and PEDOT. As a result, PEDOT:PSS:CNTs electrode presents a high conductivity of 3264.27 S cm^–1 with a high transmittance over 85%, and ITO-free PSCs based on PEDOT:PSS:CNTs electrode achieves a PCE of 7.47% with high stability. Furthermore, a large-scale flexible electrode was obtained by a roll-to-roll technique, which demonstrates an excellent property with a sheet resistance of 17 Ω sq^–1 and 80.7% optical transmittance. Combining the flexible and conductive PEDOT:PSS:CNTs film with the scalable roll-to-roll process, we anticipate that the commercial production of a large-scale transparent electrode, replacing ITO, will be realized in the near future.