Achieving Low-Voltage Operation of Intrinsically-Stretchable Organic Light-Emitting Diodes

摘要

A minimum operating voltage of intrinsically-stretchable organic light-emittingdiodes (ISOLEDs) is always required for practical applications. However, thelack of protocols for the lamination complicates the task of attaining a reliableISOLED without inducing degradation. Here, a solvent-vapor-assisted lamination(SVAL) method to reinforce the cathode interface is presented; this processlowers the operation voltage and increases the stretchability of ISOLEDs.Achieving a uniform contact and strong adhesion at the interface is the key toattaining reliable lamination. A cold-pressing (CP) treatment is applied first toreduce the surface roughness of silver nanowires before the surface embeddingprocess. A subsequent solvent vapor treatment before the laminationpartially solvated the surface of the active layer with an increase in the segmentalmotion of polymer chains, which substantially increases the interfacialadhesion after lamination. The combination of CP and SVAL treatmentsconsiderably reduces threshold voltage Vth (i.e., voltage at which currentshows an abrupt increase for light-emission) from 6.7 to 2.7 V. The ISOLEDalso exhibts excellent mechanical stretchability, with no significant changein luminance under 30 strain. This study can assist in the development ofpractical applications of intrinsically-stretchable optoelectronic devices.