排列式塊材異質接面之有機-無機混合式太陽電池

Ordered bulk heterojunction in organic-inorganic hybrid solar cells

賴奎元(Kuei-Yuan Lai)

指導教授 ： 洪勝富

國立清華大學/電機資訊學院/電子工程研究所/碩士(2006年)

摘要

共軛高分子太陽電池因具有質輕、製程簡易、可製作大面積等特色，向來為研究低成本太陽電池的一個重要領域。在元件結構上，一般是使用塊材異質接面(bulk heterojunction)結構，利用其具大面積激子分離區域的優點，使元件有較佳的表現效率。近年來，染料感光太陽電池及小分子太陽電池，均分別發展出更理想的排列式塊材異質接面結構(ordered bulk heterojunction)，使載子的傳輸效率提高，大幅增加元件的轉換效率。
本研究以P3HT (poly(3-hexylthiophene))共軛高分子為電洞傳輸材料，5nm×10nm硒化鎘(CdSe)無機膠體奈米管為電子傳輸材料，摻雜混合(blend)而為主動層材料，以旋轉塗佈(spin-coating)的方式在元件上形成單層塊材異質接面結構，在532nm單頻光下的能量轉換效率可達1%。而為了使元件達到較好的載子傳輸效率，以單層塊材異質接面結構為基礎，使用旋轉塗佈法形成多層結構，來模擬排列式塊材異質接面結構。在實驗中，利用奈米晶體受熱固結(sintering)的特性，可控制讓元件中層與層之間僅些微互溶，達成理想的多層異質接面結構。
在研究中，成功製作出blend/CdSe及blend(P3HT-rich)/blend排列式塊材異質接面結構，其元件串聯電阻較單層塊材異質接面結構減小了數倍，使元件的光電流及填充因子均大幅的提升。在能量轉換效率上，blend/CdSe雙層結構在單頻光的照射下高達2.4%，blend(P3HT-rich)/blend雙層結構更高達3.1%！

關鍵字

排列式塊材異質接面 ； 旋轉塗佈 ； 固結

並列摘要

Polymer solar cells exhibit many advantages such as the lightweight、processing feasibility and the potential to scale up to large area. Therefore polymer solar cells have been under intensive research. It usually contains single layer bulk heterojunction structure in the device. With large area for exciton separating, the efficiency of the device can be greatly improved. Recently, a better structure called ordered bulk heterojunction has been developed in dye-sensitized solar cells and molecular solar cells. It helps carriers transport and increases the efficiency of the device dramatically.
In our study, we use P3HT conjugated polymer as hole transport material and 5nm×10nm CdSe inorganic colloidal nanorods as electron transport material. Blending two of them as the active layer, we form a bulk heterojunction film on the device with spin-coating. Under the illumination of monochromatic light with 532nm wavelength, the power conversion efficiency reaches 1%. In order to increase the carrier transport efficiency, we use single layer bulk heterojunction as basic structure and develop multilayer structure with spin-coating to achieve the similar effect of ordered bulk heterojunction. Using the sintering property of nanocrystals when annealed, we can create multilayer bulk heterojunction structure by slightly mixing the layers at the interface.
In this study, we successfully developed blend/CdSe and blend(P3HT-rich)/blend ordered bulk heterojunction structures. Comparing to single layer bulk heterojunction, the series resistance decreases several times in ordered bulk heterojunction structure. It makes short circuit current and fill factor increase largely. The power conversion efficiency in blend/CdSe structure is 2.4% under the illumination of monochromatic light with 532nm wavelength. In blend(P3HT-rich)/blend structure, the efficiency even reaches 3.1%！

並列關鍵字

ordered bulk heterojunction ； spin-coating ； sintering