The Role of Redox Doping in Organic Electronics and Opto-electronics*

Organic semiconductors and hybrid/organic materials have attracted interest for electronic applications due to their potential for use in low-cost, large-area, flexible electronic devices. Here we will report on recent developments pertaining to n-dopants that could impact the charge injection/collection processes in organic light emitting diodes, organic field effect transistors, and organic photovoltaic and hybrid organic/inorganic perovskite devices. I will highlight the application of n-doping for the development of electron injection layers for organic light emitting diodes (OLEDs), and their use for doping of electron transport materials which result in high conductivities and in some cases good thermoelectric performance. In the case of OLEDs, it will be shown that photoactivation (as illustrated in the cartoon at the right) can lead to stable doping of materials (i.e., the doping induced conductivity remains relatively constant over hundreds of hours) beyond the expected thermodynamic limit, which would be predicted based on an assessment of the effective reduction potential of the n-dopant and the reduction potential of the electron transport material. We will also highlight some of the differences between approaches based upon "dimeric" dopants vs. hydride donor dopants.