Preparation of Fluorinated Graphene Nanosheets for Polymer Photovoltaic Devices
|關鍵字:||石墨烯;高分子太陽能電池;graphene;polymer solar cell|
|摘要:||本研究中我們提出一個新穎的氟化石墨烯的製備方法，利用紫外光照射氟化石墨的N-甲基吡咯烷酮分散液中，可以有效的幫助氟化石墨烯的剝除，從穿透式電子顯微鏡與原子力顯微鏡的分析可得知氟化石墨烯奈米片的厚度約為3 nm，比以傳統超音波震盪製備的氟化石墨烯更薄，顯示此方法有較好的效率。我們也發現氟化石墨烯奈米片能以旋轉塗佈的方式沉積的基板，並作為高分子太陽能電池中之電子傳輸層。實驗結果發現，反式結構元件的開路電壓為0.53 V，短路電流密度為10.22 mA cm-2，填充係數為53.7 %，功率轉換效率可達到2.91 %，而以傳統超音波震盪製備的氟化石墨烯為電子傳輸層的元件效率僅為1.73%。此較低的效率可能源於較大的厚度所致，使得氟化石墨烯奈米片本身的電阻過高，影響了它作為電子傳輸層的表現。|
In this study, we describe the preparation of fluorinated graphene nanosheets (FGS) through photoexfoliation from fluorinated graphite (FG) in liquid phase. We discovered that the use of UV radiation upon the FG dispersion in N-methyl-2-pyrolidone could facilitate the exfoliation of FGS. From the analysis of the images obtained from transmission electron microscopy and atomic force microscopy, the average thickness of the FGSs was ca. 3 nm, which was thinner than that of the nanosheets prepared using conventional sonication approach. Furthermore, the FGS can be uniformly deposited on the substrates by spin coating and behaved as an effective electron transport layer of polymer solar cells (PSCs). The as-prepared inverted PSC exhibited an open circuit voltage of 0.53 V, a short circuit current density of 10.22 mA cm-2 and a fill factor up to 53.7%., resulting in a power conversion efficiency (PCE) of 2.91%. The PCE of the PSC containing FGS prepared through sonication was 1.73%. The lower efficiency was probably due to the higher contact resistances, which may be originated from the higher thickness of the FGS.