本論文探討共軛高分子的分子堆積、除潤運動與拉伸造成的發光增益。首先，藉由旋轉塗佈參數的改變，我們發現共軛高分子主鏈上的π-π作用力影響分子鏈堆積，透過同步輻射低掠角x-光反射率量測，得知共軛高分子在奈米薄膜內有明顯的分層結構，並由於基材凡德瓦爾力不同的作用力，有不同的堆積方式，造成不同的發光效率。再著，於共軛高分子奈米薄膜的除潤運動，當分子鏈與基材產生大規模的流變與剪切，受拘束與拆散的分子鏈抑制electron-phonon coupling，進而造成發光增益與發光峰的藍位移。藉由低掠角x-光反射率與共焦螢光光譜儀量測，我們發現除潤後~2奈米的殘留薄膜具備較高的發光效率，並且沒有exciotn quenching的基材效應。而除潤液滴在除潤過程中收集流變與剪切運動的分子鏈，同樣產生較佳發光增益，但由於分子鏈易產生鬆弛現象造成存活時間較短。此外從時間單光子計數系統量測中，我們發現除潤的高分子薄膜，受拘束與流變的MEH-PPV高分子鏈有效抑制non-radiactive relaxation，導致exciton lifetime增加與鉅大的發光增益。最後在拉伸共軛高分子薄膜螢光偏極與磁光量測，發現分子鏈的極限拉伸抑制分子鏈electron-phonon coupling，造成分子鏈內的巨大螢光增益，尤其在偏極方向平行拉伸方向的反應最顯著。此研究結果有助於共軛高分子光電行為的探討與實際的元件應用。

Enhancement of photoluminescence in conjugated polymer thin film induced by chain packing, dewetting and stretching was investigated in the thesis. At first, by varying the parameter in spin casting we found that molecular chain packing was highly sensitive to the condensation process owing to the π-π interactions at the backbone of conjugated polymer, MEH-PPV. Grazing-angle x-ray reflectivity data revealed the bi-layered structures in the ultrathin polymer films which showed strong dependence on the van der Waals interactions from the substrate and illustrated various PL efficiencies. Second, long distance flow and shearing in MEH-PPV molecular chain during thermal dewetting prevailed the reduction of electron-phonon coupling which resulted in large PL enhancement. The blue shifting PL spectra was attributed by molecular constraint and separation on the substrates during dewetting. By measuring grazing-angle x-ray reflectivity and con-focal PL spectra, it found that largest luminescenece efficiency and exciton quenching switching-off at the dissociative heterojunction took place in ~2 nm dewetting residual film. Dewetting droplets also showed PL enhancement resulted by accumulating the moelcuar chain flowed and sheared in dewetting processes, however, the poor survival time was resulted from chain relaxation and degradation. Furthermore, effective reduction of non-radiactive relaxation in flowed and constrained MEH-PPV polymer chains by dewetting behavior resulted in increased exciton lifetime and enhanced PL effeciecny was invesigated by TCSPC system. Finally, the suppression of electron-phonon interaction also investigated by measurement of polarized fluorescence emission and magneto-optical effect in stretched conjugated polymer film. Fluorescence enhancement of intra-chain emission was obviously exhibited at the parallel direction of polarized excited laser and tension. These research bear important implications for the exploration of fundamental optoelectronic properties of conjugated polymers and their applications in polymer-based devices.

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