Control of electrical doping is indispensable in any semiconductor device, and both efficient hole and electron doping are required for many devices. In organic semiconductors, however, electron doping has been essentially more problematic compared to hole doping because in general organic semiconductors have low electron affinities and require dopants with low ionization potentials that are often air-sensitive. In a recent study, a team of researchers, including Stephen Barlow of the School of Chemistry and Biochemistry and the Center for Organic Photonics and Electronics, adapted an efficient molecular doping method, so-called ion-exchange doping, to dope electrons in a polymeric semiconductor.