近紅外光磷光OLED發光材料及應用寬頻藍光OLED光源於光療之研究

Abstract

有機發光二極體Organic Light Emitting Diode（OLED）因具備自發光、面光源、可撓性、低熱輻射與光譜可設計等優勢，已被廣泛應用於次世代顯示與照明技術中，並於近年展現於生醫光電領域中的光療應用潛力。光療為一種非侵入式的醫療手段，透過特定波長的光照射人體，以達到促進傷口癒合、舒緩慢性疼痛或治療黃疸等目的。 紅光與近紅外光（600–1000 nm），適合應用於深層光療，包括組織修復、血液循環改善與疼痛緩解。然而，目前相關的 OLED 材料如 Iridium 錯合物磷光發光材料仍面臨效率低與壽命短等挑戰。為此，本論文與深圳大學材料學院楊楚羅教授及張友明博士合作，開發基於 [−2, −1, 0] 電荷配位組合的 Ir(III) 錯合物 OLED 發光元件。楊教授與張博士透過 bph、acac 與 bpy 配體的組合，成功設計出五種有機發光材料，使其展現深紅至近紅外的發光特性。這些新材料具備高熱穩定性、易昇華與純化等優勢，藉由光物理分析與透過發光元件優化後，製作出低驅動電壓之近紅外光 OLED 元件。 藍光（450–480 nm）則是新生兒黃疸光療的關鍵波段，主要透過觸發膽紅素的光異構化反應來促進其代謝。目前臨床應用大多採用高功率 LED 作為光源，但其高熱與體積龐大的特性不利於長時間照射。相比之下，OLED 具備面光源與低熱特性，因而成為理想的替代方案。然而，傳統藍光 OLED 多為窄頻發光，難以完整涵蓋膽紅素的吸收波段，為解決此挑戰，本論文採用藍光螢光材料 BCzVBi 與磷光材料 FIrpic 組成 tandem 結構，成功開發出涵蓋 430–530 nm 的寬頻藍光 OLED，能完整覆蓋膽紅素主要的吸收範圍，該元件可於 13–14 V 的驅動電壓下穩定運作，表面溫度維持在 42°C 以下，並展現 10–30 μW/cm²/nm 的光譜功率密度，展現了良好的穿戴應用潛力。

Organic light-emitting diodes (OLEDs) have emerged as a core technology for next-generation display and lighting applications due to their unique advantages, including self-emission, planar light sources, mechanical flexibility, low thermal radiation, and tunable emission spectra. In recent years, these features have also demonstrated great potential in biomedical optoelectronics, particularly for phototherapeutic applications. Phototherapy is a non-invasive medical approach that uses specific wavelengths of light to modulate physiological functions or treat pathological conditions, such as wound healing, chronic pain relief, and neonatal jaundice treatment. Red and NIR (Near-Infrared Red) light (600 – 1000 nm) possess strong tissue penetration, making them suitable for deep-tissue phototherapy applications such as promoting tissue regeneration, improving blood circulation, and relieving pain. However, current phosphorescent OLED materials for this spectral range, such as iridium-based complexes, face major challenges including low emission efficiency and short device lifetimes. To address these issues, this study collaborated with Professor Chuluo Yang and Dr. Youming Zhang from the College of Materials Science and Engineering at Shenzhen University to develop Ir(III)-based phosphorescent emitters using a novel [−2, −1, 0] ligand coordination scheme. Professor Yang and Dr. Chang successfully designed five organic luminescent materials using combinations of bph, acac, and bpy ligands, exhibiting deep red to NIR emission properties.These new materials exhibit high thermal stability, good sublimation properties, and excellent purity. With detailed photophysical characterization and device optimization, low-driving-voltage red and NIR OLEDs were successfully fabricated. Blue light（450–480 nm）plays a critical role in phototherapy for neonatal jaundice by inducing the photoisomerization of bilirubin, thereby accelerating its metabolic clearance. Currently, high-power blue LEDs are the dominant clinical light source, but their large form factor and high thermal output pose risks for prolonged exposure to infants’ eyes and skin. In contrast, OLEDs offer uniform surface emission and low heat generation, making them promising alternatives. However, traditional blue OLEDs often emit narrowband spectra, limiting coverage of bilirubin’s absorption range (460–490 nm). To overcome these limitations, this study developed a tandem OLED structure combining a fluorescent blue emitter (BCzVBi) and a phosphorescent sky-blue emitter (FIrpic), achieving a broadband emission spanning 430–530 nm. This spectrum effectively covers the primary absorption range of bilirubin. The resulting devices operate stably at 13–14 V, maintain a surface temperature below 42 °C, and deliver a spectral power density of 10–30 μW/cm²/nm, making them well-suited for wearable phototherapy applications.