n‑Type Doping\nEffect of Anthracene-Based Cationic\nDyes in Organic Electronics

n-Type doping for improving the electrical characteristics\nand\nair stability of n-type organic semiconductors (OSCs) is important\nfor realizing advanced future electronics. Herein, we report a selection\nmethod for an effective n-type dopant with an optimized structure\nand thickness based on anthracene cationic dyes with high miscibility\ninduced by a molecular structure similar to that of OSCs. Among the\ndoped OSCs evaluated, rhodamine B (RhoB)-doped OSC exhibits the highest\ndensity, a smallest roughness of 2.69 nm, a phase deviation of 0.85°\naccording to atomic force microscopy measurements, and the highest\nelectron mobility (μ), showing its high miscibility. Surface\ndoping of RhoB affords the lowest contact resistance of 2.01 ×\n10<sup>5</sup> Ω cm compared to bulk and contact doping, resulting\nin an effective doping structure. The RhoB-doped OSC retains 81.63%\nof the original μ value of 6.13 × 10<sup>–2</sup> cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> after\n15 days, whereas pristine OSC shows a lower μ of 2.33 ×\n10<sup>–2</sup> cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> and maintains only 4.41% of the original value after\n15 days. Our findings demonstrate that this methodology is effective\nfor the selection of a high-performance n-type dopant for OSCs toward\nthe development of high-performance and air-stable n-type organic\nelectronics.