Lin, X.; Wegner, B.; Lee, K.M.; Fusella, M.; Zhang, F.; Moudgil, K.; Rand, B.; Barlow, S.; Marder, S.; Koch, N.; Kahn, A.: Beating the thermodynamic limit with photo-activation of n-doping in organic semiconductors. Nature Materials 16 (2017), p. 1209-1215
10.1038/NMAT5027
Open Access Version
Abstract:
Chemical doping of organic semiconductors using molecular dopants plays a key role in the fabrication of ecient organic electronic devices. Although a variety of stable molecular p-dopants have been developed and successfully deployed in devices in the past decade, air-stable molecular n-dopants suitable for materials with low electron affnity are still elusive. Here we demonstrate that photo-activation of a cleavable air-stable dimeric dopant can result in kinetically stable and effcient n-doping of host semiconductors, whose reduction potentials are beyond the thermodynamic reach of the dimer’s effective reducing strength. Electron-transport layers doped in this manner are used to fabricate high-effciency organic light-emitting diodes. Our strategy thus enables a new paradigm for using air-stable molecular dopants to improve conductivity in, and provide ohmic contacts to, organic semiconductors with very low electron affnity.