請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/45124
標題: | 使用溶液製程開發有機無機三明治結構太陽能電池 Development of Polymer Solar cells with Organic-Inorganic Sandwiched Structures through Solution Processing |
作者: | Jing-Shun Huang 黃敬舜 |
指導教授: | 林清富(Ching-Fuh Lin) |
關鍵字: | 高分子太陽能電池,過渡金屬氧化物,溶液製程,界面改植, polymer solar cell,metal oxides,solution process,interfacial modification, |
出版年 : | 2010 |
學位: | 博士 |
摘要: | 隨著能源需求增加,尋找替代性能源越趨重要。光伏科技-可將太陽光能直接轉換為電能,被視為是未來極有可能取代石油成為全球能源來源之一。由共軛高分子與富勒烯衍生物所組成的太陽能電池近年來吸引了各界極大的注意,它實現了可印刷、可攜帶、可撓曲及低成本的優勢,但在此種太陽能電池中,其吸光層的奈米形貌具有不易精準控制的問題,影響了吸光層中載子的傳輸;不僅如此在高分子太陽能電池中有機層與電極介面、有機材料與無機材料介面載子傳輸的控制亦是相當具有挑戰性的工作。此外,電極介面的品質對於高分子太陽能電池的穩定性具關鍵性的影響。
此論文是以發展有機無機三明治結構高分子太陽能電池為主軸,也就是有機吸光層夾於兩層無機半導體層中間,此結構擁有高效率、穩定性與低成本的優勢。首先,製備及分析無污染、生長於水溶液的氧化鋅奈米柱陣列,在其低退火溫度下的氧化鋅奈米柱,垂直排列於基板,並有擁有約50 nm直徑、柱與柱間距約10-50 nm的特性,這些對於溶液製程的低成本有機無機太陽能電池邁進相當重要;在高度排列的氧化鋅奈米陣列存在下,為了達成更加有效的激子分離效率與載子傳輸,在本論文中提出三種方式來改善高分子/氧化鋅奈米柱混成太陽能電池介面問題。這三種方式分別為:額外的富勒烯衍生物聚集層增加了相分離與光吸收;加入二氧化鈦奈米粒子來形成雙異質接面(double heterojunction)結構,提供更有效的激子分離效率與載子傳輸;最後,利用氧化釩奈米粉末的導入來抑制漏電流並同時增加光吸收。隨著富勒烯衍生物聚集層、TiO2奈米粒子與V2O5奈米粉末的加入,使能量轉換效率從2.3%分別增加至3.2%、4%與3.6%。 此外,為了發展有機無機三明治結構,我們分別以氧化鎳、氧化釩、氧化鎢以及氧化銅等四種金屬氧化物來修飾電池陽極,並以氧化鋅做為電洞阻擋層來修飾電池陰極,以探究倒置結構高分子太陽能電池。氧化鎳、氧化釩與氧化銅有利於電洞傳輸,氧化鎳與氧化釩更擁有了高位障可阻擋電子,因此抑制了陽極處的漏電流;另外,高功函數的氧化鎢有利於將電洞從有機層傳導至銀電極。我們研究發現加入任一氧化層,能量轉換效率均可改善至~3.7%。相對於這些個別的氧化物,我們更進一步研究氧化釩-氧化鎢混合型氧化層對陽極的修飾效果,因為它們具有互補的特性。在此類研究中,我們分別使用了P3HT:PCBM 與PV2000兩種系統作為吸光層。兩種吸光系統均會因三明治結構(就是有機吸光層夾於混合型氧化層與氧化鋅層中間)的導入使得漏電流被抑制,光吸收與量子效率也因混合型氧化層獲得改善;此外,混合型氧化層在空氣中相當穩定,因此氧化層可保護有機吸光層避免氧氣或水氣的破壞,提升元件的耐久性;因此能量轉換效率在P3HT:PCBM系統中可提升至4.16%,在PV2000系統可提升至5.13%。 此外,這些介面修飾層與三明治結構全都是由溶液製程方法製作,相對於真空沉積技術,溶液製程方法是簡單的、迅速的並且是有效的,這對於量產各種大面積、低成本印刷式電子與光電產品是十分具有潛力的應用,亦是極大的優點;更值得一提的是,我們開發的方法可提供相當的便利性來製作任何特定比例的混合氧化物層;這並不容易藉由熱蒸鍍法達成,因為不同的氧化物擁有不同的沸點。 As the search for alternative sources of energy other than fossil fuels continues to expand, photovoltaic technology (direct conversion of solar energy into electrical energy) has been identified as one of the promising technologies. Solar cells based on blends of conjugated polymers and fullerene derivatives have recently attracted significant attention due to their great promise for the realization of printable, portable, flexible, and low-cost renewable energy sources. However, it is not easy to precisely control the nanoscale morphology of photoactive layer which seriously affects the carrier transport. In addition, control of the charge transport at organic-electrode or organic-inorganic interface is also challenging in polymer-based solar cells (PSCs). Quality of the electrode interface is also critical for the PSC stability. This dissertation focuses on the development of PSCs with organic-inorganic sandwiched structures (organic photoactive layer sandwiched between two inorganic semiconductor layers), which exhibit high efficiency, air-stability, and low cost. First, environmentally friendly ZnO nanorod arrays grown in an aqueous solution are presented. At a low annealing temperature (130 ℃), the ZnO nanorod arrays align very vertically with rod diameter of 50 nm and rod-to-rod spacing of 10-50 nm. This provides a solution-based route to the fabrication of low-cost organic-inorganic photovoltaic devices with highly oriented ZnO nanorod arrays. In order to achieve better exciton dissociation and charge transport, three types of interfacial modifications are demonstrated in the PSCs hybridized the ZnO nanorod arrays. The addition of PCBM clusters can enhance the phase separation and optical absorption. Inserting TiO2 nanoparticles leads to a formation of double heterojunction, providing efficient exciton dissociation and charge transfer. The insertion of V2O5 nanopowder can suppress the leakage current and enhance the absorption. With the PCBM clusters, TiO2 nanoparticles, and V2O5 nanopowder, the power conversion efficiencies (PCEs) can be improved from 2.3% to 3.2%, 4%, and 3.6%, respectively. Moreover, in order to develop the organic-inorganic sandwiched structures, four kinds of metal oxides, NiO, V2O5, WO3, and CuO, as anodic modifications are explored in inverted PSCs with ZnO film at cathode as hole blocker. NiO, V2O5, and CuO are beneficial for hole transport. NiO and V2O5 further have high barriers against electrons, thereby suppressing leakage current at the anode. WO3 is beneficial for the electron extraction from Ag into P3HT. With one of these oxides, PCE can be improved from ~3% to ~3.7%. In addition to the individual oxides, WO3-V2O5 mixed oxides as anodic modification are also studied because they are complementary. P3HT:PCBM and PV2000 are used as the photoactive layer, respectively. With the sandwiched structure consisting of mixed oxides and ZnO film, the leakage current can be suppressed. The optical absorption and quantum efficiency are also improved by the mixed oxides. Additionally, the mixed oxides are relatively stable in air, so they can protect photoactive layer therein from the oxygen or water damaging and thus improve device durability. As a result, the PCEs are improved to 4.16% for the P3HT:PCBM system and to 5.13% for the PV2000 system, respectively. Furthermore, these interfacial modifications and the sandwiched structures are all fabricated by solution approaches. Compared to the vacuum-deposited techniques, these approaches are simple, expeditious, and effective. They are also advantageous for potential applications to mass production of various large-area printed electronics and photonics with a very low cost. In addition to the low cost, the solution process provides the convenience of mixing different kinds of oxides in a desired ratio, which cannot be easily achieved by thermal co-evaporation due to the different boiling points of oxides. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/45124 |
全文授權: | 有償授權 |
顯示於系所單位: | 光電工程學研究所 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-99-1.pdf 目前未授權公開取用 | 10.94 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。