Intrinsically stretchable organic light-emitting layers by using a high-vinyl polybutadiene elastomer blended with small molecule/polymer hosts and a highly doped TADF guest

Stretchable organic light-emitting diodes (OLEDs) demonstrate significant application potential in electronic skin, bionic robotics, and wearable electronics, where the intrinsically stretchable emitting layers ( is -EMLs) serve as the core functional component. This study employs a facile and eco-friendly strategy by blending high-vinyl-content polybutadiene (HVPB) elastomer with two types of is -EMLs: an all-small-molecule EML and a hybrid EML of polymer host and small molecule guest. Under optimal mass ratios, the all-small-molecule is -EML exhibited enhanced crack onset strain (COS) of 10 %, accompanied by a 16.3 % improvement in maximum external quantum efficiency (EQE max ) for corresponding OLEDs. Remarkably, the COS of the polymer/small molecule hybrid is -EML exceeded 100 %, with its corresponding device demonstrating 44.1 % enhancement in EQE max . Phase separation was identified as the primary mechanism responsible for the improved stretchability of the is -EMLs. These two is -EMLs exhibit distinct application prospects in the stretchable OLEDs based on their differing luminescent and mechanical tensile properties. • We blended a small molecule emitting layer (EML)-MCP:CzPXZ (EML M ) and a polymer host/small molecule guest hybrid EML-PVK:CzPXZ (EML P ) with a high-vinyl polyethylene elastomer (HVPB) to achieve intrinsically stretchable EMLs ( is -EMLs). • When the mass ratio of EML M to HVPB reaches 10:3.5, the crack onset strain (COS) of the film of EML M :HVPB ( is -EML M ) is increased to 10%. Compared with the rigid OLED based on EML M , the maximum external quantum efficiency (EQE max ) of the device based on is -EML M increased by 16.3%. • When the mass ratio of EML P to HVPB reaches 10:5, the COS of the film of EML P :HVPB ( is -EML P ) is more over 100%. Compared with the OLED based on EML P , the EQE max of the device based on is -EML P increased by 44.1%.