Research

Inorganic and organic material-based quantum dots (QDs) are emerging as next-generation nanoemitters for advanced optoelectronic applications. Among these, two-dimensional (2D) materials such as graphene, MoS₂, and MXene offer significant advantages due to their large surface area, unique photoluminescence (PL) properties, and excellent electrical and mechanical characteristics. Carefully engineered post-surface treatments further enhance PL efficiency and enable diverse optoelectronic applications (Adv. Mater.; Adv. Funct. Mater.; Adv. Mater.). This work aims to develop novel synthetic strategies that prioritize eco-friendliness and sustainability while achieving high PL quantum yield (PLQY), superior color purity, and multifunctionalities, surpassing the performance of conventional approaches. 

Triplet excited states-based long-lived afterglow emissions, including room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF), offer significant advantages for applications in displays, bioimaging, and data security. A notable example demonstrates the concept of tunable singlet-triplet energy splitting in graphene quantum dots (GQDs) by varying the ratio of oxygenated carbon to sp² carbon (Adv. Mater.). Matrix-assisted stabilization of triplet excited states extends the afterglow lifetime of both RTP and TADF while mitigating aggregation-induced quenching (Chem. Phys. Rev.). We are exploring novel engineering strategies to improve afterglow efficiency and lifetime, aiming for integration into optoelectronic devices with enhanced external quantum efficiency (EQE).

Our research extends beyond material synthesis to the scalable applicability of quantum dots (QDs) across various domains. One example is an integrated heavy metal ion detection system based on the lab-on-a-chip concept, utilizing a fluorescence switching mechanisms (Anal. Chem.; Biosen. Bioelectron.). The application of graphene QDs (GQDs) includes electroluminescent devices (Adv. Mater.), down-conversion white light-emitting diodes (WLEDs) (Adv. Funct. Mater.), and photoluminescence (PL)-based anti-counterfeiting systems featuring ultralong afterglow emission (Adv. Mater.). Additionally, we explore QD-based platforms that enhance the sensitivity of harmful gases such as NOx by integrating GQDs with semiconductor metal oxide nanoarrays (Nanoscale Adv.).

Skin-integrated systems with thin, flexible, and stretchable designs enable seamless adaptation to various body regions, offering programmable, spatiotemporal thermo-haptic stimulation for enhanced VR/AR immersion. Recent effort highlights passive cooling mechanisms, thermally switchable interfaces, and wireless, stretchable electronics as key components for energy-efficient, programmable thermal stimulation with closed-loop control (Proc. Natl. Acad. Sci. U.S.A.). Another platform leveraging passive cooling enables continuous, low-cost, wireless monitoring of cerebrospinal fluid flow (Biosens. Bioelectron.). Future research aims to develop high-density thermo-haptic arrays with energy-efficient actuation and extend flow sensing capabilities to other biofluids, such as sweat and blood.