以溶液製程製作低溫鈣鈦礦太陽能電池及結合軟性基板之研究

Abstract

本篇論文第一部份利用TiO2 nanoparticle 取代高溫製程TiO2，並以快速結晶(Drop-Casting)的溶液製程製作低溫鈣鈦礦太陽能電池，我們接著將從電子傳輸層TiO2、主動層Perovskite做優化。在優化TiO2的部分，我們探討元件在不同濃度、層數、轉速、後退火溫度之下TiO2的表現，而在優化主動層Perovskite層的部分，分別測試了Perovskite的厚度、後退火溫度這兩個條件，研究過程中我們利用AFM量測perovskite的厚度，也以SEM及來觀測Perovskite在不同後退火溫度下的結晶顆粒，分析Perovskite結晶的型態及完整度。最後在Spiro層以及上電極金完成後，我們製作出填充係數66.45、轉換效率13.42%的低溫鈣鈦礦太陽能電池。 在第二部分的研究中，我們嘗試將第一部份所製作的低溫鈣鈦礦太陽能電池製作於軟性基板上，並討論TiO2不同層數對於元件的影響，透過SEM探討TiO2層數增加對於元件的影響，我們發現隨著層數增加，TiO2覆蓋率上升使得元件表現提升。在TiO2三層時製作出轉換效率為6.67%的元件。我們接著對元件進行折彎穩定性測試，發現以曲率半徑2.5mm折彎元件500次後，元件效率能保有原先效率的91%。為了改善ITO的導電性，我們在ITO和TiO2中間塗佈Pedot，並分析塗佈Pedot對元件的影響。

In the first part of this thesis, We synthesize TiO2 nanoparticles and fabricate low-temperature Perovskite solar cells in conventional structure using drop-casting solution process. Device performance was sequentially improved by several testing, including concentration, layer number, spin rate and the annealing temperature of TiO2 nanoparticles which serve as electron transporting layer (ETL) in perovskite solar cell. Annealing temperature and spin rate of Perovskite layer are also discussed in this part by analyzing the Scanning electron microscopy(SEM) figure of Perovskite of different temperature and measuring thickness of Perovskite at different spin rates, respectively. It proves that the drop-casting process, a fast and simple process, is beneficial for complete crystallization of Perovskite . We also discuss the difference between low-temp.(<150℃) TiO2 process and high-temp.( 550℃) sintering TiO2 by using AFM to measure the morphology of different TiO2 film and discussing its impact on the device performance. Finally the power conversion efficiency of the low-temperature Perovskite solar cells in this study has reached 13.42%, with a fill factor (F.F) of 66.45%. In the second part, we fabricated perovskite solar cell on flexible substrate. We found out that with the increase of TiO2 layer, the coverage of TiO2 increases, which is proved by AFM figure of different layer TiO2. Our best cell with tri-layer TiO2 has reached a power conversion efficiency of 6.67% . We also tested the bending stability of our flexible devices. After 500 bending cycles with radius of curvature set at 2.5mm, 91% of the original efficiency has remained. In order order to increase the conductivity of ITO on PEN substrate, we use Pedot between ITO and TiO2 and discuss the effect of Pedot.