金屬鉛鹵化物鈣鈦礦：穩定性、發光二極體應用及神經毒性評估

Abstract

鈣鈦礦奈米晶體（PeNC）已為一值得注意且具發展性之材料，具卓越之光學性能，使其為光電應用之理想選擇。然而，基於 PeNC 之設備之商業化具關鍵挑戰之阻礙，其涵蓋毒性、穩定性及可發展性。本研究全面探討金屬鹵化鉛鈣鈦礦奈米晶體（PeNC）相關之挑戰，並提出解決此些問題之方案，並強調其多樣化應用，例如白光發光二極體（WLED）與微型發光二極體（μLED）。 第一部分為保護 CsPb(Br,I)3 與 CsPbBr3 PeNC，使用有機矽樹脂和聚甲基丙烯酸甲酯基質合成高效穩定之紅色與綠色 PeNC薄膜。紅色及綠色薄膜均實現高 PLQY（紅色高於 43%，綠色高於 94%），且改善其熱穩定性。此保護策略有效抑制鹵化物離子之擴散與未配位之鉛，使此些PeNC薄膜可應用於WLED，且具143.4% National Television Standards Committee (NTSC)寬色域。 第二部分研究則致力於開發無溶劑 PeQD 墨水，用於高效率之綠光與紅光 LED 背光與微型 LED 顯示。經由流體系統，首先製得 PLQY 極高之PeQDs（紅光 CsPb(Br,I)3 達 92%，綠光 CsPbBr3 接近 100%）。再於三甲氧基矽烷與 3-(三甲氧基矽基)丙基甲基丙烯酸酯之協同作用下，成功將 PeQDs 均勻分散於可光固化之1,6-己二醇二丙烯酸酯單體中，製得無溶劑 PeQD 墨水。此策略不僅解決墨水生產中有毒溶劑之使用問題，亦改善 PeQDs 之穩定性。此無溶劑 PeQD 墨水展現穩定且明亮之紅光與綠光，長期穩定性亦表現優異：CsPb(Br)3維持 100% 螢光強度長達 115 天，CsPb(Br,I)3則達 78 天。此外，此無溶劑墨水可噴墨列印，製備均勻且高亮度之 PeQD 薄膜，並於柔性顯示應用中展現出色彩坐標接近標準值之 100.28% ITU-R Recommendation BT.2020 (Rec. 2020) 色域表現。 於第三部分研究中，使用線蟲 Caenorhabditis elegans 作為模型生物，全面評估 CsPbBr3 PeNCs 的神經毒性。研究結果顯示，PeNCs 將於腸道系統與頭部累積，導致運動能力下降、咽部泵作用受損、生殖異常及壽命縮短。神經毒性反應與過量活性氧（ROS）產生及基因表現變化有關，突顯需開發無毒材料或加強保護機制以降低金屬鉛鹵化物鈣鈦礦材料之潛在風險。 經由此些研究，本論文旨於推動鈣鈦礦奈米晶體技術之發展，並促進其於光電應用中之廣泛實施。藉解決毒性、穩定性及可擴展性等關鍵挑戰，本研究期望為 PeNC 基礎裝置之安全與永續發展奠定堅實基礎。

Perovskite nanocrystals (PeNCs) have emerged as a noteworthy and promising group of materials with exceptional optical properties, making them ideal candidates for various optoelectronic applications. However, the commercialization of PeNC-based devices is hindered by several critical challenges, including toxicity, stability, and scalability. This doctoral thesis offers a comprehensive exploration of the challenges associated with metal lead halide perovskite nanocrystals (PeNCs) and proposes solutions to address these issues while also highlighting their diverse applications, such as white light-emitting diode (WLED) and micro light-emitting diode (μLED). The first project is carried out to protect both CsPb(Br,I)3 and CsPbBr3 PeQDs for producing highly efficient and stable red and green PeQD films using silicone resin and poly(methyl methacrylate) matrices. Both red and green films achieve high photoluminescence quantum yield (PLQY) (above 43% for red and 94% for green) with improved thermal stability. The protective strategy effectively suppressed halide ion diffusion and uncoordinated lead, allowing these PeQD films to be applied in WLEDs with a broad color gamut of 143.4% National Television Standards Committee (NTSC). The second study aimed to fabricate a solvent-free PeQD ink with high-efficiency green and red PeQD inks for LED backlighting and micro-LED displays. Herein, by using a fluidic system, we first obtained super-high PLQY PeQDs (92% for red CsPb(Br,I)3, and nearly 100% for green CsPbBr3 PeQDs). Then the non-solvent PeQD ink is uniformly obtained in curable 1,6-hexanediol diacrylate monomer thanks to the assistance of the mixture of trimethoxysilane and 3-(trimethoxysilyl)propyl methacrylate. This strategy solves the challenges of using toxic solvents in ink production as well as addressing the problems of the instability of PeQDs. Our solvent-free PeQD ink also exhibits bright and stable green and red emissions with long-term stability, retaining 100% PL intensity after 115 days for CsPbBr3 and 78 days for CsPb(Br,I)3. The nonsolvent ink enables uniform, bright PeQD films with inkjet compatibility for flexible displays, achieving a 100.28% ITU-R Recommendation BT.2020 (Rec. 2020) color gamut with red and green coordinates near reference values. In the third work, the comprehensive neurotoxicity of CsPbBr3 PeNCs using the nematode Caenorhabditis elegans as a model organism is performed. Our findings show that PeNCs accumulate in the alimentary system and head, leading to reduced locomotion, impaired pharyngeal pumping, reproductive issues, and shortened lifespan. The neurotoxic effects are linked to excessive reactive oxygen species (ROS) formation and gene expression changes, highlighting the need for the development of nontoxic materials or greater protection methods for metal lead halide perovskite. Through these studies, this thesis aims to propel the progress of perovskite nanocrystal technology and encourage its widespread implementation in optoelectronic applications. By addressing the critical challenges of toxicity, stability, and scalability, this research aims to ensure the safe and sustainable development of PeNC-based devices.