無重金屬量子點材料合成與發光二極體應用

Abstract

半導體量子點因具有獨特的發光特性，其具有高色彩純度、能階可調性與可延展性，將其應用於發光二極體為現今科技之趨勢，目前於應用端表現最好之量子點材料鎘，以及新興的無機鈣鈦礦量子點CsPbX3(X=Cl、Br與I)卻都因為其材料中重金屬的毒性而限制了其商用化的發展，對於環境的影響也是一大隱憂，因此目前許多研究都是為了尋求替代的材料。 本篇論文中，我們首先較安全便宜之六甲基三氨基磷作為前驅物用熱注射法合成無重金屬之磷化銦/硫化鋅核殼量子點，其合成出來之相對量子效率大約60.1%，放光之半高寬為42nm，並測試此材料之熱穩定度發現其在七十度時製作發光二極體元件具有最佳之量子效率，此元件開啟電壓5 V，在12 V時具有最高亮度160 cd/m2，在6.7 V時外部量子效率為0.223%，雖然此種效率還無法拿來實際應用，但其具有環保與低成本，在未來具有極高的潛力。 再來我們將CsPbCl3中的Pb使用錫與錳做取代，成功合成出量子點，對其做光學鑑定及結構鑑定，發現其吸收值隨錳比例增加而有藍移的現象，並具有螢光，雖然量子效率並不高，但此種材料也為無重金屬量子點開啟了新篇章。Semiconductor quantum dots have unique optical properties, like high-luminescent, high color purity and wide color gamut which depend on both size and shape. Nowadays, the best performing quantum dots at the application end are CdSe. However, due to the toxicity of the Cd have limited the commercialization. The high luminescent inorganic perovskite quantum dot CsPbX3 (X=Cl, Br and I), which are also been limited because of the Pb. The impact on the environment is also a major concern, as a result many studies are currently seeking alternative materials, that are environment-friendly. In this work, heavy-metal-free InP/ZnS core/shell QDs were prepared by (DMA)3P precursors, which are low cost and safe. The InP/ZnS core/shell QDs with fluorescence quantum yield of 60.1%, and full width at half maximum of 42 nm were applied as an emission layer to QD-LEDs. The QD-LEDs showed the turn-on voltage at ~ 5 V, the highest luminance (160 cd/m2) at 12 V, and the external quantum efficiency of 0.223% at 6.7 V. Overall, InP/ZnS core/shell QD-LEDs reveal potential to be the heavy-metal-free QD-LEDs for future display applications. On the other hands, we replace the Pb ions in CsPbCl3 crystals with Sn(II) ions and Mn(II) ions. Mn: CsSnCl3 had been successfully synthesis, and characterized optical properties and structure properties. Although the photoluminescent performance is not ideal, the material open an new option for Heavy-Metal free quantum dots.