CBE Colloquia - Development, doping and device applications of n-type polymers 

The advance of organic electronics field relies on the design and synthesis of high-performance p-type and n-type organic/polymer semiconductors with comparable device performance. However, the performance of n-type polymers lags far behind their p-type counterparts, hence limiting the advance of organic electronics. The development of high-performance n-type polymers hingers on the design and synthesis of highly electron-deficient building blocks with small steric hindrance, planar backbone, compact geometry, and good solubility. In this talk, I will present a series of imide-functionalized ladder-type bithiophene imide (BTI) derivatives with up to five imide groups, and the polymer semiconductors built from them show remarkable performance in various n-type organic (opto)electronic devices. On another hand, chemical doping is a fundamental tool for tuning charge carrier density, Fermi level, and electrical conductivity of organic semiconductors and improving device performance. However, n(electron)-doping is much more challenging than p(hole)-doping and typically achieves a much lower doping efficiency. I will discuss our discoveries on catalyzed molecular n-doping technique based on various catalysts, including vapor deposited transition metal nanoparticles, solution-processable surface-functionalized transition metal nanoparticles, and soluble organometallic complexes.