拉伸式太陽能電池之製作與特性分析

Abstract

有機太陽能電池由於其為乾淨綠能源、可以低成本製造，並且可以溶液製備生產，因此已經發展了許多年。在本篇論文中，我們製作可拉伸的有機太陽能電池元件並且製備出應用於光伏元件的可拉伸之電子傳輸層與非富勒烯光敏層。 藉由褶皺方式製備具機械韌性之可拉伸反式有機太陽能電池 (第二章)：本研究製備出可拉伸之反式有機太陽能電池，其方法為將元件製作在超薄聚萘二甲酸乙二醇酯塑膠膜上並與預拉伸100%的3M VHB4905膠帶做結合。當釋放預拉後則元件產生皺摺，使其可承受進一步的應力，如此一來可改善元件的機械韌性和拉伸性。因此，我們使用此方法製備元件，其效率為5.61%。內文會探討元件之形變程度與反覆拉伸的耐久度對電性的影響。相較於初始效率，於30%收縮程度的效率仍可維持原先的74%。此外，當反覆拉伸50次，元件效率仍可維持起初的64.3%。此結果證明藉由使用此法製備可拉伸式有機太陽能電池具備良好的機械耐久性並可成為超薄且輕巧的能源之潛力。 透過電荷選擇層與光敏材料工程製備可拉伸式有機太陽能電池 (第三章)：本研究首先運用PFN/NBR混摻系統製備出可拉伸式電子選擇層。該PFN/NBR的DMT模數為0.45Gpa遠低於純PFN (DMT模數為1.25GPa)，且可以承受60%之高應變而不產生裂痕。除了增加PFN的拉伸性之外，NBR的末端羧酸基可以使PFN離子化以促進其在極性溶劑中的可加工性，並確保在元件的相應界面處形成界面偶極矩，如FT-IR和UPS分析。通過進一步使用非富勒烯受體替代PCBM，使得光敏層具有更好的機械拉伸性，證明可改善有機太陽能電池的拉伸性和元件電性。非富勒烯受體的太陽能電池元件在10％拉伸後PCE為2.22％，其拉伸性超過了僅能承受5％應變的PCBM元件。此研究提供普遍的方式製備全拉伸有機太陽能電池。

Organic solar cells (OSCs) have been developed for several years due to clean energy source, low-cost manufacturing, and roll-to-roll solution production. In this thesis, we fabricated mechanically robust, stretchable OSCs by buckle-on-elastomer strategy and prepared stretchable electron selective layer (ESL) and non-fullerene photoactive layer to realize intrinsically stretchable organic photovoltaic devices. Mechanically robust stretchable inverted organic solar cells via buckle-on-elastomer strategy (chapter 2): We fabricated an efficient, stretchable inverted organic solar cells by adopting a buckle-on-elastomer strategy, for which an ultrathin poly(ethylene naphthalate) (PEN) substrates coupled with a pre-strained (100 %) 3M elastomeric VHB 4905 tape was employed as the device substrate. Once the pre-strain was released, the formation of wrinkles accommodated further strain, which can afford the derived OSC with a much improved mechanically robustness and stretchability. As a result, we demonstrated a pristine OSC with the PCE of 5.61% using this method. The effects of mechanical deformation and durability on electrical performance were investigated. Compare to the pristine device, the PCE can remain its 74% efficiency under 30 % compression, and furthermore, can still retain its 64.3% efficiency after 50-cycle compression and stretching testing from 0 % to 30 % compression. This work proves that utilizing buckle-on-elastomer strategy can realize the stretchable organic photovoltaics with reasonably good mechanical duribility, which can become a potential for an ultrathin and lightweight power source. Realization of intrinsically stretchable organic solar cells enabled by charge-selective layer and photoactive material engineering (chapter 3): We first fabricated a blend of PFN and NBR (Nipole®1072) as stretchable electron-selective layer. This PFN/NBR layer exhibited a much lower Derjaguin-Muller-Toporov (DMT) modulus (0.45 GPa) than the value (1.25 GPa) of the pristine PFN and could withstand a high strain (60% strain) without showing any cracks. Moreover, besides enriching the stretchability of PFN, the terminal carboxyl groups of NBR can ionize PFN to promote its solution processability in polar solvent and to ensure the interfacial dipole formation at the corresponding interface in the device, as evidenced by the FT-IR and UPS analyses. By further coupling the replacement of PCBM with non-fullerene acceptors owning better mechanical stretchability in the photoactive layer, OSCs with improved intrinsically stretchability and performance were demonstrated. An all-polymer OSC exhibited a PCE of 2.22% after 10% stretching, surpassing the PCBM-based device that can only withstand 5% strain. This work provides a universal strategy for the development of intrinsically stretchable organic photovoltaics.