本研究聚焦於由多成分主動層所製作的有機光感電晶體。此多成分主動層由三種半導體，如poly(3-hexylthiophene-2,5-diyl) (P3HT)、n,n’-Ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13)與tris(8-hydroxyquinolinato)aluminium (Alq3)所疊加組成。此多成分光感電晶體除了具備偵測紫外光和可見光波段，且能夠快速分辨紫外光與可見光。本論文分為三部分。第一部分探討了有機主動層從單一層到三層間其相應元件之電與光特性。第二部分研究了多成分主動層之基本光學性質，並探討元件之光與電的相關性。第三部分提供了一理論機制其解釋元件在紫外光照射下呈現的特殊電性行為，因此達到分辨的效果。

本文第一部分中，以P通道半導體P3HT為基底並搭配額外兩種N型半導體PTCDI-C13和Alq3組成。藉由三種照射光源，探討了多成分光感電晶體之光敏性。相較於單層P3HT光感元件，P3HT/Alq3與P3HT/PTCDI-C13元件呈現較佳的光敏性。尤其是P3HT/Alq3雙層主動層，其對應元件在照射紫光時會產生特殊的電性行為。例如，當元件在空乏型量測時，其電流呈現延遲下降現象;當元件在增強型量測時，其電流顯示了快速下降現象。相對的，在照射綠光時，元件在空乏型量測時，其電流也呈現延遲下降現象。但元件在增強型量測時，其電流卻不會出現下降現象。因此，透過上述結果其可達到分辨紫光與綠光。此外，透過三層主動層P3HT/PTCDI-C13/Alq3所製作的光感電晶體元件，其可解決當照射紫光時元件之電流延遲下降現象。

本文第二部份中，利用光譜學如吸收光譜、光致發光光譜(photoluminescence, PL)與光激發螢光光譜(photoluminescence excitation, PLE)來探討多成分半導體之光學特性。再者，研究多成分光感元件之電特性與光源間的相關性，並更進一步探討出特殊電性行為的可能起源。

本文第三部份中，我們提出一理論機制，其探討了多成分主動層光感電晶體之特殊電性現象。透過基本的電學性質與光學特性，我們可合理的說明此特殊電性行為的起因與過程。

In this study, several kinds of multicomponent-based organic phototransistors (OPTs) were fabricated: poly(3-hexylthiophene-2,5-diyl) (P3HT) as an active layer and visible light absorber, n,nʹ-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI) as an electron acceptor and visible light absorber, and tris(8-hydroxyquinolinato)aluminum (Alq3) as a UV light absorber and electron acceptor. The photosensitivity of the multicomponent-based OPTs with a p-n heterojunction improved compared with that of the neat P3HT-based OPTs. Upon ultraviolet light illumination, P3HT/PTCDI/Alq3-based OPTs exhibited maximum values of photosensitivity (P) and photoresponsivity (R) of 102 and 1.83 mA/W, respectively. Under green light illumination, the maximum P and R of the P3HT/PTCDI-based OPTs were 5×103 and 0.47 mA/W, respectively. Different photoresponse characteristics were obtained among these OPTs operated in different modes, such as the photocurrent decay speed and positive or negative photoresponse features. The possible origins were discussed in terms of the energy band model and electron mobility of the top Alq3 and PTCDI layer. OPTs that could distinguish UV light from visible light were successfully produced mainly on the basis of their negative or positive photoresponse characteristics.

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