準二維鈣鈦礦具備高光致發光量子產率與多重量子井結構，是極具潛力的雷射增益材料。然而，溶液製程易形成低維相，不僅抑制了能量由高帶隙相向低帶隙相的順利傳遞，也導致非輻射復合增強，進而限制了其整體發光效率與增益表現。
本研究採用 N,N-二甲基乙醯胺（DMAc）作為溶劑，製備出低粗糙度、結晶性佳且垂直排列之高品質 (PEA)2(MA)3Pb4I13 薄膜。瞬態吸收光譜（TAS）顯示，其高 n 相具能量轉移時間低於 0.5 ps 的優勢，代表更有效率的載子聚集與發光行為。
最終我們從脈衝雷射觀察到放大自發輻射的特性，證實形貌與相分佈控制可有效提升載子能量轉移效率與發光表現，對未來高效率光電雷射元件開發具有關鍵意義。

Quasi-two-dimensional (quasi-2D) perovskites, featuring high photoluminescence quantum yield and multi-quantum well structures, are regarded as promising gain media for laser applications. However, during solution processing, the spontaneous formation of low-dimensional (low-n) phases often suppresses efficient energy transfer from wide-bandgap to narrow-bandgap domains and enhances nonradiative recombination, ultimately limiting emission efficiency and optical gain.
In this study, we employed N,N-dimethylacetamide (DMAc) as the processing solvent to fabricate high-quality (PEA)2(MA)3Pb4I13 films with low surface roughness, improved crystallinity, and vertically aligned structures. Transient absorption spectroscopy (TAS) reveals that the high-n phases exhibit ultrafast energy transfer with characteristic times below 0.5 ps, indicating efficient carrier funneling and radiative recombination behavior.
The observation of amplified spontaneous emission under pulsed excitation highlights the effectiveness of morphology and phase control in enhancing energy transfer and emission performance, offering valuable insights for future high-efficiency laser device design.

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