Harmonizing High Phosphorescence Efficiency and Stretchability in Flexible Afterglow Materials Through Microphase Engineering.

Abstract

Organic ultralong room-temperature phosphorescence (OURTP) materials are promising for flexible optoelectronics but often suffer from a trade-off between phosphorescence efficiency and mechanical flexibility. To overcome this limitation, a block copolymer system is developed through the incorporation of coronene into poly(styrene-isoprene-styrene) (SIS). Within this structure, the rigid polystyrene (PS) segments immobilize the phosphors and facilitate charge-transfer-mediated OURTP, resulting in high phosphorescence efficiency (Φ = 54.9%, τ = 6.26 s). Concurrently, the polyisoprene (PI) segment ensures outstanding elasticity, endowing the material with ultra-stretchability (2380.5% strain) and fatigue resistance (withstanding 600% strain over 40 cycles). The system also maintains intrinsic morphological homogeneity, effectively avoiding phase separation. Through microphase engineering, this work successfully reconciles the long-standing conflict between luminescence and flexibility, providing a general design strategy for multifunctional polymers suitable for wearable electronics that demand both deformability and phosphorescent capability.