基於表面鈍化與添加劑工程之二維鈣鈦礦發光二極體

Abstract

本論文針對準二維鈣鈦礦材料於發光元件中的應用進行研究，聚焦於表面鈍化、結構掌性與添加劑工程三項關鍵技術，探討其對元件效率、穩定性及自旋極化發光的影響。在第一項工作中，選用RP型準二維鈣鈦礦 PEA2(FAPbBr3)2PbBr4 作為材料，透過熱退火與 TOPO 鈍化劑進行優化。結果顯示，90 °C退火60分鐘並搭配4 mg/mL TOPO處理可有效提升結晶性、抑制非輻射復合，並增加光致發光量子產率與外部量子效率，證實表面工程可改善元件性能。第二項工作是合成R-/S-NEABr掌性準二維鈣鈦礦，分析不同結構相組成與掌性光學特性。當樣品同時具有n = 2相時，激子可進行能量遷移並維持掌性訊息，產生CPL；反之，僅具n = 1結構者則雖有CD訊號但無CPL表現。元件應用上，本研究設計兩種LED架構。Type 1 LED以掌性鈣鈦礦為發光層，證實老化後之422樣品可產生CPEL。Type 2 LED則以掌性層作為CISS過濾層，搭配Super Yellow為發光層，僅於新鮮且添加[BMIm]OTf條件下觀察到明顯CPEL訊號。綜上，結構分層與介面優化對於掌性鈣鈦礦在自旋光電元件中的應用具有關鍵意義，亦展現其發展潛力。This dissertation investigates the application of quasi-2D perovskite materials in light-emitting devices, focusing on three key strategies: surface passivation, structural chirality, and additive engineering. The effects of these approaches on device efficiency, operational stability, and spin-polarized light emission are systematically explored.In the first part, a RP-type quasi-2D perovskite, PEA2(FAPbBr3)2PbBr4, was employed and optimized through thermal annealing and post-treatment with trioctylphosphine oxide (TOPO). Annealing at 90 °C for 60 minutes, combined with 4 mg/mL TOPO treatment, effectively improved crystallinity, suppressed nonradiative recombination, and enhanced both photoluminescence quantum yield (PLQY) and external quantum efficiency (EQE), confirming the role of surface engineering in performance improvement.The second part focuses on the synthesis and characterization of chiral quasi-2D perovskites using R-/S-NEABr. Optical and structural analyses revealed that samples containing both n = 1 and n = 2 phases enabled exciton funneling while preserving chiral information, resulting in circularly polarized luminescence (CPL). In contrast, samples with only n = 1 phases exhibited strong circular dichroism (CD) but no CPL emission. Two LED architectures were developed to evaluate device-level performance. Type 1 LEDs employed chiral perovskites as the emissive layer, with aged 422 samples demonstrating detectable circularly polarized electroluminescence (CPEL). Type 2 LEDs used the chiral layer as a chiral-induced spin selectivity (CISS) filter and Super Yellow as the emissive layer; a measurable CPEL signal was observed only under fresh conditions with ionic liquid ([BMIm]OTf) incorporation.Overall, this study highlights the importance of phase hierarchy and interfacial optimization in achieving spin-polarized emission and demonstrates the potential of chiral quasi-2D perovskites in next-generation spin-optoelectronic applications.