Highly Transmissive,\nProcessable, Highly Conducting\nand Stable Polythiophene Derivatives via Direct (Hetero)arylation\nPolymerization

The development of modern optoelectronic\ndevices increases\nthe\nneed for lightweight and flexible transparent conductors. It is thus\nessential to develop new eco-friendly materials that can be easily\nprocessed for the fabrication of such devices. For this purpose, the\nsynthesis of self-doped, highly conducting, transmissive, and water-processable\npolythiophene derivatives was performed via the direct heteroarylation\npolymerization method and a protection/deprotection strategy. Stable\nconductivities up to 1000 S cm<sup>–1</sup> have been obtained.\nChampion materials (<b>P1</b> and <b>P7</b>) were scaled\nand processed via the roll-to-roll compatible slot-die coating method\nto demonstrate their large area applicability. The best coated films\nexhibited optical transmittance greater than 79% at 550 nm with sheet\nresistances of 116 Ω □<sup>–1</sup>. These values\nare comparable to indium–tin oxide on plastic and thus present\na viable alternative to metal oxide-based electrodes.