準二維與自旋選擇性鈣鈦礦之材料與元件特性研究

Abstract

本篇文章是以準二維（Quasi-2D）鈣鈦礦為目標的研究，涵蓋範圍包括有機–無機鈣鈦礦之特性與電子自旋選擇之旋光鈣鈦礦為主，其中也包括R-P相（Ruddlesden-Popper Phase）與D-J相（Dion-Jacobson Phase）鈣鈦礦的特性探討。在有機–無機鈣鈦礦的部分，本文選擇CsPbBr_xCl_(3-x)作為鈣鈦礦單位晶格的材料，並選擇有機長鏈4-F-PMABr（4-Fluoro-benzylammonium bromide）作為層狀結構間的連結，旨在利用鹵素的比例變換調變能隙與引入適當長鏈材料後所引發的量子侷限效應（Quantum Confinement Effect）而達成調配適當藍光的結果。在調配光色步驟完成後，透過引入「電洞傳輸層TFB（Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)]）」、「電子阻擋層PVK（Poly(9-vinylcarbazole)）」以及「電子傳輸層TPBi（2,2′,2-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)）」以上幾種方式提升元件之量子效率，並以其他穩態性質的量測來分析材料之特性。而我們在這項研究中，成功的將外部量子效率（External Quantum Efficiency, EQE）提升到了4.208%。元件效率最佳化後，本文將熱活化延遲螢光發光材料（Thermally Activated Delayed Fluorescent,TADF）依照比例參入鈣鈦礦前驅液當中，並成功達成了單層混合光色的發光元件。至於在自旋選擇之旋光鈣鈦礦中，本文透過D-J相鈣鈦礦的特性並引入具有雙胺（diamine）之長鏈分子作為層狀結構間的連結。在本研究中，本文不同於以往選擇了具有不對稱性的雙胺基長鏈4-AMPBr_2（4-(Aminomethyl)piperidine bromide）以取代以往多具有對稱性的雙胺基長鏈，達成由結構不對稱所引發的自旋選擇與旋光特性，並藉由圓二色性光譜儀（Circular Dichroism Spectrophotometer , CD）與圓偏振螢光光譜儀（Circularly Polarized Luminescence Spectrophotometer , CPL）的量測探討其對於圓偏振光的吸收以及激發圓偏振之螢光分析。This thesis is based on research of Quasi-2D Hybrid Organic-Inorganic Perovskites (HOIPs) and Chirality Induced spin selectivity (CISS) Perovskites, also including the principle of Ruddlesden-Popper Phase Perovskite (RPP) and Dion-Jacobson Phase Perovskite (DJP).The first part is about the optical properties and electrical characteristic of HOIPs devices. We synthesized the Quasi-2D Perovskite by using CsPbB"r" _"x" C"l" _"3-x" and organic long chain molecule 4-F-PMABr. Our research reach the target by tuning the proportion of halogen, adding organic long chain molecule 4-F-PMABr into perovskite layer, and motivating the Quantum Confinement Effect to realize the blue emission. We introduced the Hole Transport Layer : “TFB (Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4’-(N-(4-sec-butylphenyl)diphenylamine)])” , Electron Blocking Layer: “PVK (Poly(9-vinylcarbazole))” , Electron Transport Layer: “TPBi(2,2’,2-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole))”. The efficiency of perovskite light emitting diodes was up to the high performance (External Quantum Efficiency = 4.208%). After that, The Thermally Activated Delayed Fluorescent (TADF) was add into the perovskite precursor solution, and achieved a single emissive layer to form the light emitting diode successfully.The second part is the chiral-optical property and devices of Chiral perovskite. We synthesized the Chiral Perovskite by MAPbB"r" _"3" and 4-AMPB"r" _"2" (4-(Aminomethyl)piperidine bromide). 4-AMPB"r" _"2" has the characteristic of diamine rather than single amine that it has the potential to form DJP, also it has the property of structure asymmetry, which means 4-AMPB"r" _"2" -based perovskite will be observed the chirality by Circular Dichroism Spectrophotometer (CD) and Circularly Polarized Luminescence Spectrophotometer (CPL).