To achieve conformal and monolithic integration between biological tissues and electronic systems, the development of high- performance soft conductors is essential. We have engineered functional nanocomposites and nanomembranes by synthesizing and assembling shape-controlled nanomaterials and strategically embedding them within soft elastomers. As a result, we developed nanocomposites and nanomembranes with outstanding electrical and mechanical properties, including high stretchability (^(M)Science, 2021), strain-insensitivity (^(ⅰ)Advanced Materials, 2022), and metal-like conductivity (^(ⅱ)Advanced Materials, 2023), and isotropic electrical properties (^(ⅲ)Advanced Materials, 2025) Furthermore, we synthesized core-shell nanowires for longer material stability (^(ⅳ)Nature Nanotechnology, 2018) and demonstrated their applicability in soft bio-interfacing for heart (^(ⅴ)Science Translational Medicine, 2016) and peripheral nerve (^(ⅵ)Advanced Materials, 2021 ). By bridging nanoscale material innovation and biomedical device application, our research aims to advance the field of biomedical engineering.

Hydrogels possess mass-permeable, ultra-soft, and low-impedance material properties. These characteristics make functionalized hydrogel-based stretchable bioelectronics well-suited for achieving high-quality, stable, long-term tissue-device interfaces. For example, a highly conductive and adhesive hydrogel engineered with nanomaterials was introduced (^(ⅰ)Advanced Materials, 2024), enabling efficient electroceutical applications. Furthermore, we are advancing both material systems and fabrication techniques that allow for precise patterning and seamless integration of functionalized hydrogels with flexible and stretchable bioelectronics, crucial for optimizing the device performance (^(ⅱ)Science Advances, 2021; ^(M)Science Advances, 2024). Such integration enhances device functionality, enabling real-time health monitoring through advanced sensing capabilities. These innovative technologies hold great promise for a wide range of applications, including rehabilitation, long-term health monitoring, point-of-care treatment, and disease prevention.

Our research group is at the forefront of developing advanced post-silicon electronic materials that serve as the foundation of next-generation devices. For instance, we demonstrated a stretchable carbon nanotube transistor using a vacuum-deposited polymer dielectric that can enable stretchable active matrix systems (^(ⅰ)Nature Electronics, 2023). In parallel, we engineered covalent heterostructures of ultrathin amorphous carbon nitride and silicon, which have enabled high-performance vertical photodiodes and rectifying devices (^(M)Nature Synthesis, 2025). Additional examples include our ultrathin phototransistor array based on MoS₂ and graphene (^(ⅱ)Nature Communications, 2017), as well as high-resolution spin-on-patterning technique for perovskite thin films (^(ⅲ)Advanced Materials, 2017), further reinforcing our commitment to pioneering electronic material and device technologies.

Soft implantable bioelectronics create engineered interfaces that mechanically match cardiac tissues, enabling stable, low-impedance coupling with the beating heart. We design device architectures and wireless system modules optimized for chronic cardiovascular use, ensuring reliable operation under continuous dynamic deformation. In detail, we developed high-efficiency wireless communication and power-transfer technologies suitable for deep-tissue implantation (^(M)Nature Reviews Bioengineering, 2024; ^(ⅰ)Science Advances, 2022), enabling continuous monitoring of electrophysiological and hemodynamic signals essential for detecting arrhythmia, ischemia, and early heart-failure progression. We also engineered minimally invasive sensors, soft stimulators, and compact RF-ablation tools to reduce surgical burden and increase procedural precision in interventional cardiology (^(ⅱ)Nature Communications, 2015; ^(ⅲ)Advanced Materials, 2024). In addition, our conformal multichannel epicardial electrode arrays provide high-resolution conduction mapping and targeted modulation of arrhythmogenic regions (^(ⅳ)Science Advances, 2023). Cell-sheet–based approaches further offer complementary potential for cardiac tissue regeneration (^(v)Nature Communications, 2019). Together, these technologies establish a foundation for next-generation, closed-loop cardiac bioelectronic systems for personalized cardiovascular diagnostics and therapy.

Focusing on the development of Quantum Dot-based flexible and stretchable displays, our research group is dedicated to pioneering advancements in next-generation display technologies. We proposed high-efficiency full color QLED arrays by using high-resolution intaglio transfer printing (^(ⅰ)Nature Communications, 2015). We also developed an ultrathin skin-attachable QLED display (^(ⅱ)Advanced Materials, 2017) that can visualize various information acquired from wearable electronics. Furthermore, we demonstrated highly bright and transparent QD-LEDs (^(ⅲ)Advanced Materials, 2017) with an ultrathin form factor and high color purity. Based on ultrathin QLEDs, we reported 3D foldable QLEDs (^(ⅳ)Nature Electronics, 2021), utilizing controlled folding techniques to create customized 3D architectures. We also fabricated intrinsically stretchable QLEDs (^(M)Nature Electronics, 2024) that can be stretched without significant brightness loss. Recent developments in stretchable QD color converters have further expanded the potential of stretchable display technologies (^(v)Advanced Materials, 2025).

Our research on unconventional energy harvesting, storage, and saving devices aims to provide sustainable and clean energy solutions. We developed stretchable energy harvesting systems and wearable energy storage devices suitable for integration with mobile electronics(^(ⅰ)Advanced Functional Materials, 2017). Furthermore, we introduced biocompatible and biodegradable batteries (^(ⅱ)Advanced Materials, 2021), specially designed for safe and long-term operation in human-friendly electronic systems. To improve the portability and practical usability of wearable and implantable electronics, we also developed a high-quality flexible thin-film battery utilizing a damage-free dry transfer method (^(M)Nature Materials, 2024). In addition, we developed transparent and colored photovoltaic devices for sustainable and distributed solar power generation (^(ⅲ)Nature Communications, 2022), and passive cooling devices for energy saving strategies (^(ⅳ)Advanced Materials, 2025)Collectively, these technologies represent a step forward in energy device technologies for a sustainable energy future.