High-Performance Stretchable Electroluminescent Polymer and OLEDs

Stretchable optoelectronics represent an emerging frontier in materials science and device engineering, with the potential to transform applications ranging from wearable displays to implantable biomedical systems and soft robotics. By combining mechanical compliance with superior optical performance, stretchable OLEDs (organic light-emitting diodes) are uniquely positioned to provide skin-like light sources and displays that can intimately integrate with the human body. However, the development of intrinsically stretchable OLEDs remains a fundamental challenge, as introducing stretchability often compromises charge transport, exciton management, and overall device efficiency. As a result, the performance of stretchable OLEDs has long lagged behind that of their rigid counterparts, limiting their technological feasibility. In my Ph.D. research, I focused on advancing intrinsically stretchable OLEDs at both the materials and device levels with three overarching objectives: imparting stretchability into emissive materials while preserving luminescent efficiency, addressing the bottleneck of carrier injection and transport, and suppressing exciton quenching to achieve commercial-level device performance. First, I developed a polymer design strategy that integrates thermally activated delayed fluorescence (TADF) units with linear alkyl linkers to achieve high stretchability without sacrificing light-emission properties. Systematic experiments and computational simulations demonstrated that long alkyl linkers enable effective strain dissipation, resulting in record-breaking electroluminescent efficiencies for intrinsically stretchable emitters. Second, to overcome the longstanding challenge of inefficient electron injection, I created a novel design for stretchable electron-transport layers (ETLs) with tailored energy levels and high electron mobility. In parallel, I engineered stretchable aluminum electrodes using a nano/microstructural strategy based on the liquid-metal embrittlement effect. Together, these approaches enabled fully stretchable OLEDs with performance metrics approaching those of rigid commercial devices. Third, I introduced a host–guest design strategy for stretchable TADF systems, where small-molecule guests are uniformly dispersed within a stretchable polymer host. This architecture not only suppressed triplet–triplet annihilation but also enhanced chain dynamics, significantly boosting device efficiency beyond 20%. This framework provides a versatile platform for integrating diverse emitters, enabling both high efficiency and broad color tunability. In summary, this body of work establishes a cohesive foundation for high-performance intrinsically stretchable OLEDs by uniting emissive polymer engineering, charge transport and electrode design, and host–guest material strategies. Collectively, these advances demonstrate that stretchable OLEDs can achieve performance rivaling rigid systems, thereby paving the way toward commercially viable, skin-like optoelectronic devices for next-generation human-interactive technologies.