以芴基衍生物為基礎之有機光子與感測元件

Abstract

有機半導體薄膜因其在光子與光電上的應用，在近二十年來受到廣泛的重視於研究。在本論文中，我們研究以芴為主體之寡聚物的各種光電元件。 首先，我們使用一對具施子及受子特性之含芴基寡聚物製作出紫外光偵測器，該偵測器擁有高量子效率且對可見光無反應。 接著，我們研究寡聚芴薄膜的光學特性，發現它們擁有高度的光學非等向性，然而當它們被加熱到接近玻璃轉換溫度後，薄膜則變成呈現光學等向性。這意味著分子在薄膜中方向具有可調變特性。利用這個特性，我們研究分子方向對有機薄膜誘發放光特性的效應。利用此性質，我們也成功的在單一樣本上展示了誘發放光波長的可調性。 最後，我們製作以寡聚芴為感測層的氧氣感測器。該元件有高感受度與快速的反應時間。而利用薄膜的誘發放光特性，感受度可進一步提升。

Thin films of organic semiconductors have been subjected to extensive studies in the last two decades due to applications in photonics and optoelectronics. In this thesis, we investigate various optoelectronic devices based on fluorene-cored oligomers. In the first part of the works, we employed two fluorene-cored oligoaryls, which are found to be an efficient donor-acceptor pair in the active organic layer of ultraviolet photodetectors. The devices exhibit high external quantum efficiency and high visible blindness. In the second part of the works, we studied the optical properties of oligofluorene vacuum-deposited thin films and found that they show high optical anisotropy but become optical isotropic after annealing at a temperature around the glass-transition temperature. The results indicate the molecular reoriention in thin films after annealing. Using this property, we investigated the influence of molecular orientation on stimulated emission properties of organic thin films. Employing such properties, we have also demonstrated continuous tuning of the stimulated emission wavelength of a slab waveguide within one sample. Finally, we employed the oligofluorene thin film for oxygen sensing. The material itself exhibits moderate sensitivity and fast response. The sensitivity can be further enhanced using stimulated emission of the thin films.