隨著石化燃料的蘊藏量日漸減少，尋找其他符合經濟效益的替代能源，成為迫在眉睫的工作。有機太陽能電池(OPVs)具有低成本、多色彩、可撓曲及適用溶液製程等優點，成為近年來能源研究重點，為了得到更高的光電轉換效率的OPVs，許多科學家致力於主動層材料的開發，特別是主動層中p型共軛分子的合成。本論文即設計以Quinoxaline稠環單元做為中心片段，以3-hexylthiophene延長共軛， 加上4-(5-(2-ethylhexyl)thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5] thiadiazole (BT-EH)為兩端手臂，合成出可作為OPVs主動層材料之p型(電洞傳輸材料)小分子半導體S5和S6，其在二氯甲烷中最大吸收波長皆為 540 nm，吸收係數為51600 M-1cm-1 和54900 M-1cm-1，成膜後的最大吸收波長則分別為595 nm和605 nm。以S5和S6為P型材料混摻PC71BM作為主動層所組裝成的有機太陽能電池，在AM 1.5 G模擬光源照射下，光電轉換效率分別為0.51%和0.31%。;The dwindling of the fossil fuel reserves, searching for other cost-effective alternative energy has become an urgent work. Organic photovoltaics (OPVs) is one of hot research topics of the green energy due to their eminent advantages such as low cost, colorful, flexibility and solution-processable. Many scientists put their efforts in designing new material of active layer, especial p-type conjugated moecules, to increase the photovoltaic conversion efficiency (PCE) of OPVs. In this thesis, we designed and synthesized two new organic small molecule semiconductor S5 and S6 for applying as a p-type semiconductors in OPVs. These two molecules comprise a quinoxaline or a fused-ring, as the core unit, 3-hexylthiophene as a conjugate moiety and BT-EH (4-(5-(2-ethylhexyl) thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5] thiadiazole) as arms attached on each side. The absorption spectra (in dichloromethane) of both S5 and S6 have the an absorption maximum at 540 nm and molar absorption coefficient of 51600 M-1cm-1 and 54900 M-1cm-1, respectively. The bulk heterojunction (BHJ) organic photovoltaic devices based on these two organic p-type semiconductor were fabricated via solution process. When PC71BM were used as a n-type material, PCE of the devices based on S5 and S6 are 0.51% and 0.31%, respectively.