On-demand photochemical stabilization of doping in light-emitting electrochemical cells

A highly functional p–n junction doping structure can be realized within a light-emitting electrochemical cell under applied voltage via ion redistribution and electrochemical doping. This doping structure will however dissipate when the formation voltage is removed due to the mobility of the dopant counter-ions. A number of concepts aimed at a spatial immobilization of the ions and the related stabilization of the doping structure have been presented, but they all suffer from long and poorly controlled stabilization periods and/or unpractical operational conditions. Here, we introduce a markedly fast and easy-to-control stabilization procedure involving the inclusion of a UV-sensitive photo-initiator compound into a carefully tuned active material in a light-emitting electrochemical cell device, and demonstrate that it is possible to cross-link the ions and stabilize the p–n junction doping via a short UV-exposure step executed at room temperature.