本論文是在研究高分子材料型的有機太陽能電池(Organic Photovoltaic cell，OPV)，OPV是以有機半導體為主要的材料，而有機半導體在吸收太陽光的能力至少需要100~200 nm的厚度才能將其百分之九十以上的太陽能完全吸收，但是因吸收太陽光的有機半導體所產生出來的激子(exciton)擴散長度只有10~20 nm，而在激子擴散過中只有接觸到OPV中的電子供給者(donor)和電子接受者(acceptor)的介面時，因化學位勢的不同使得激子才能有效分離產生電子(electron)電洞(hole)對，電洞和電子在分別經由donor跟acceptor傳導到電極產生電能，所以在製備OPV時donor跟acceptor的接觸面積成為影響效率的重要課題。 本論文使用基質輔助脈衝雷射蒸鍍法(matrix assisted pulse laser evaporation，MAPLE)來製備OPV中的主動層(active layer)，而主動層所使用的材料是聚3-己基噻酚(P3HT)和(6,6)-苯基-C61-丁酸甲酯(PCBM)，我們透過MAPLE加上填充氣體的技術將P3HT形成奈米顆粒堆疊的方式成膜來增加膜的孔隙度，再用PCBM透過MAPLE的技術將P3HT薄膜的奈米孔隙填滿，以達到提高P3HT(donor)跟PCBM(acceptor)的接觸面積進而提升OPV的光電轉換效率，我們也嘗試了將P3HT跟PCBM一起溶在鄰二甲苯中做成靶材，用MAPLE的技術成長本體異質接面(bulk heterojunction)的OPV結構以提高P3HT和PCBM的接觸面積來提升效能，並且在MAPLE過程當中填充氣體使得P3HT和PCBM兩相分離(phase segregation)達到如同傳統製程中溶劑退火(solvent annealing)的效果。 經由實驗結果發現，具有奈米結構之OPV是雙層(bilayer)結構之OPV效率的1.5倍，而有經過熱退火(thermal annealing)的bulk heterojunction OPV又比具有奈米結構的OPV效率高2倍，但是光電流過低的問題推測是因為在我們用MAPLE製備OPV的過程中，讓P3HT和PCBM膜中增加許多缺陷導致提高電子電洞對再復合(recombination)的機率。 ;The thesis is research of Organic Photovoltaic cell (OPV) of high molecular material. OPV is mainly consist of organic semiconductor. When the organic semiconductor can absorb above 90% solar power, the thickness of it needs at least 100~200 nm. But the diffusion length of exciton which is produced by organic semiconductor which absorb solar power is only 10~20 nm. Only if the exciton contact the interface between donor and acceptor of OPV in diffusion process, the exciton will efficiently separate into the hole and electron due to difference of chemical potential. The hole and electron respectively conduct through donor and acceptor to electrode to produce electricity. Hence it is an important issue that contact area between donor and acceptor influences efficiency of OPV. In the thesis, we used matrix assisted pulse laser evaporation(MAPLE) to fabricate the active layer of OPV. The materials of active layer were poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C61-butyric acid Methyl ester(PCBM). We produced the film composed of P3HT nanoparticle with MAPLE and backfilled gas technique in order to increase porosity of the film. Then we made PCBM fill in P3HT film nanopores with MAPLE to increase the contact area between P3HT(donor) and PCBM(acceptor) and enhance the efficiency of OPV. We also tried to dissolve P3HT and PCBM in the same solvent(ortho-xylene) to made target in MAPLE with cooling system, and we produced the bulk heterojunction OPV with MAPLE to increase the contact area between P3HT and PCBM and enhance the efficiency of OPV. We also made P3HT and PCBM produce phase segregation with MAPLE and backfilled gas technique in order to achieve the effect of solvent annealing in conventional process. According to the result, we found the nanostructured OPV efficiency is half times higher than the bilayer one, and the thermal annealing bulk heterojunction OPV efficiency is twice higher than the nanostructured one. However, we guessed the reason of low current is there are many defects in film and lead to increase possibility of recombination in MAPLE process.
