Polymer Gating White Flexible Field‐Induced Lighting Device

The development of field‐induced electroluminescence (EL) devices holds great promise for the production of extremely flexible and efficient large‐area light sources. Here, a novel flexible polymeric gate layer for alternating current driven organic electroluminescence (AC‐OEL) devices is presented. The charge‐valve mechanism of carrier manipulation in forward and reversed bias of the applied AC cycles is fully detailed. With a low‐doping strategy of two phosphors in the fluorescent host, a flexible polyethylene(PET)‐based AC‐OEL device with poly[(9,9‐bis(3′‐((N,N‐dimethyl)‐N‐ethylammonium)‐propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)] gate exhibits incredible stability on EL performance with a superior color rendering index, over 81 at 2800 K color temperature and a power efficiency of 2.8 lm W⁻¹ at 1000 cd m⁻² with high bending ability (−90° to +90°).