Stretchable Liquid-Metal PDMS Encapsulation with Enhanced Water/Oxygen Barrier Properties for Perovskite Light-Emitting Diodes.

Perovskite light-emitting diodes (PeLEDs) are inherently suitable for stretchable devices owing to their mechanical flexibility and outstanding optoelectronic properties, yet their practical application remains hindered by the lack of encapsulation materials that simultaneously provide high stretchability and effective protection against moisture and oxygen. Herein, we report a stretchable densified microscale liquid metal-polydimethylsiloxane (μLM-PDMS) encapsulation layer through an integrated ultrasonic dispersion and centrifugal densification (IUCDC) strategy. Through ethanol-assisted ultrasonication, monodisperse μLM particles are generated. The abundant surface hydroxyl groups on μLM particles promote the formation of interfacial Si-O-Ga covalent bonds, enabling robust integration between μLM and PDMS matrix, thereby effectively suppressing interfacial delamination under cyclic deformation. Subsequent centrifugal densification induces the formation of a compact μLM barrier network within the PDMS matrix. The resulting μLM-PDMS encapsulation layer exhibits excellent mechanical stretchability with substantially enhanced water and oxygen barrier performance, with the water vapor transmission rate and oxygen transmission rate reduced to 1.28 and 0.3% of pristine PDMS, respectively. The encapsulation layer extends the PeLED operational lifetime (T50) by 614% under ambient atmosphere. This work provides an effective strategy for developing stretchable hermetic encapsulation materials for durable perovskite optoelectronic devices.