透明低水氣穿透塗層應用於鈣鈦礦太陽能電池封裝之研究

Abstract

本論文專注於開發氟聚合物-二氧化矽奈米複合材料，用於封裝鈣鈦礦太陽能電池並研究其物理和化學特性。它包含兩個部分，第一部分是研究和開發一種透明、低水氣穿透性（WVP）的無溶劑樹脂，第二部分是藉由通過降轉換層將紫外光轉換為可見光來提高鈣鈦礦太陽能電池的光電流。 鈣鈦礦太陽能電池對濕氣和溫度非常敏感，需要通過可在低溫加工的低水氣穿透性塗層進行保護。此外，封裝塗層必須保持透明度，以使鈣鈦礦太陽能電池能夠保持其透明性，並用於和建築物集成的結構或與矽太陽能電池串聯等。所選的塗層材料應無溶劑，以避免在應用過程中損壞鈣鈦礦層並釋放任何有害的揮發性有機化合物。 本研究製備了三種不同的氟聚合物及其聚合物樹脂和混合樹脂，即脂肪性FEVE-UA、芳香性PSFIA和它們的組合TFEVE-FIDA。樹脂的氟含量和丙烯酸官能基在確定排斥濕氣方面扮演著關鍵角色。在氟樹脂中引入無機二氧化矽填料可以進一步降低樹脂的水蒸氣透過率。二氧化矽所造成的額外界面對塗層的光穿透率和水氣透過率之影響被系統性地研究了。這些選定的封裝劑經歷了鈣鈦礦太陽能電池的加速壽命測試，並與商業封裝劑（對照組）進行了比較。我們的封裝材料在阻濕性能上與對照組相當（2.09 g∙mm/m2∙day與2.08 g∙mm/m2∙day），但透明度更高（360nm下為70.1％，400nm下為89.4％，800nm下為96.8％，對照組分別為61.4％@360nm，75.6％@400nm和87.7％@800nm）。同時，在環境中經受65℃和65％RH條件超過400小時後，封裝後的電池表現出長期穩定性。對於TFEVE-FIDA為基的複合封裝膜最低可達到0.85 g∙mm/m2∙day的水氣透過率。 光波長降轉換塗層由兩種不同的聚集誘導發光（AIE）光譜分子和聚合物基質組成。不同聚合物中的降轉換材料呈現不同的聚集狀態，從而影響塗層的光譜量子效率（PLQY）。此研究比較及討論此塗層在鈣鈦礦太陽能電池光電流增加情況相關的模擬和實驗。ZE10和ZD20降轉換塗層的光電流分別增加了約0.5 mA/cm²和0.3 mA/cm²，這帶來了約0.2％至0.3％的PCE增加，但僅為模擬值的1/3至1/4。在排除邊緣和反向側發射光後，可以合理解釋模擬與實驗結果的差異。 建議未來的工作是通過結合先前兩部分研究來準備一種可降轉發光之封裝塗層，用於鈣鈦礦太陽能電池。此樹脂不僅可以保護裝置，還可以發出可見光，有效利用非光源區域。該封裝後電池的 PCE 預計會因為光電流的增加而增加。

This thesis focuses on developing fluoropolymer-silica nanocomposites for encapsulating perovskite solar cells and analyzing their physical and chemical properties. It comprises two primary parts: first, investigating and creating a transparent, low water vapor permeability (WVP) solventless resin, and second, enhancing the photocurrent of perovskite solar cells through a down-converting layer that transforms UV light into visible light. Perovskite solar cells are highly sensitive to moisture and temperature, necessitating protection via a low-temperature processable coating with minimal moisture permeation. Additionally, the encapsulating coating must maintain transparency to enable the use of perovskite solar cells in integrated building structures or in tandem with Si solar cells. The chosen coating material should be solventless to avoid damaging the perovskite layer and releasing harmful volatile organic compounds during application. This study examined three distinct fluoropolymers, their polymeric resins, and hybrid resins, namely aliphatic FEVE-UA, aromatic PSFIA, and their combination TFEVE-FIDA. The fluorine content and acrylic functionality of the resin play a crucial role in determining their density and properties for repelling moisture. The introduction of inorganic silica filler into the fluoro resin can further decrease the WVP of the resin. The influence the coating's transmittance and WVP by creating additional interfaces from silica is systematic studied. These selected encapsulants underwent accelerated lifetime testing of perovskite solar cells and were compared with a commercial encapsulant (control). Our encapsulant has comparable moisture protection as the control (2.09 g∙mm/m2∙day vs. 2.08 g∙mm/m2∙day) but higher transparency (70.1%@360nm, 89.4%@400nm and 96.8%@800nm vs. 61.4%@360nm, 75.6%@400nm and 87.7%@800nm). Meanwhile, the encapsulated devices exhibit long-term stability when they were subjected to the environment of 65℃ and 65%RH for more than 400hrs. The lowest WVP of 0.85 g∙mm/m2∙day can be reached for TFEVE-FIDA based hybrid encapsulation film. The down-conversion coating consists of two distinct aggregation-induced emission (AIE) photoluminescence molecules and a polymer matrix. The down-converting materials exhibit different aggregation behaviors in various polymers, thereby impacting the photoluminescence quantum yield (PLQY) of the coating. The study involved the increases in photocurrent from different coatings by theoretical calculations and experimental results. The ZE10 and ZD20 down-conversion coatings gain the photocurrent approximately 0.5 mA/cm² and 0.3 mA/cm², respectively, which brings about 0.2% to 0.3% PCE increasement, only 1/3 to 1/4 of the simulated value. The mismatch can be resolved when excluding edge and reverse-side emissions. The recommended future work is to prepare a light-emitting encapsulation coating for perovskite solar cell by combining the previous two parts of research. The coating not only can protect the devices but also emit visible light which efficiently uses the non-active area of device. The PCE of this encapsulated device is predicted to be increased due to increasement of photocurrent.