- 學位論文
原子層沉積技術成長之金屬氧化物對鈣鈦礦太陽能電池的影響
Effect of atomic layer deposited metal oxides on organic-inorganic hybrid lead halide perovskite solar cells
摘要
有機無機混合甲基鉛鈣鈦礦太陽能電池由於其優異的元件效率的在近年迅速發展，然而其主動層在大氣下穩定性不佳限制了其應用，其中元件的熱穩定性又是最為根本的問題。本論文希望利用原子層沉積技術沉積緻密的金屬氧化物薄膜應用於鈣鈦礦太陽能電池元件以期解決熱穩定性不佳的缺點。我們首先整理了鈣鈦礦與不同金屬前驅物、與氧化劑之間的相容性，提供了選擇製程條件及金屬前驅物的準則。在適當參數下，加入原子層沉積極薄的氧化鋁或二氧化鈦在鈣鈦礦上所做的元件在效率上皆有不錯的表現。然而由於鈣鈦礦表面性質不利於原子層沉積技術的成核，所沉積的氧化物並非完美覆蓋表面，使得元件在熱穩定性並未有顯著的提升。為解決熱穩定性問題，我們改為沉積摻雜鋁的氧化鋅在有機的電子傳輸層上，此結構的元件效率可達14.6%，且元件在氮氣環境下經過攝氏85度一天的劣化測試後，元件效率僅降為約原本的80%，遠好於控制組元件效率降超過50%。
並列摘要
Organic-inorganic hybrid lead halide perovskite solar cells have been developed rapidly because its excellent performance. However, the active material is unstable in ambient air, which limits its practical application. Thermal instability of devices states a more fundamental problem. In this thesis, atomic layer deposited inorganic metal oxides was applied to perovskite solar cells devices in order to solve the problem. We first investigated compatibility of perovskite with a variety of metallic precursors and with oxidants, respectively. We concluded criteria of selecting condition of ALD process and choice of precursors that would not damage perovskite. With optimal parameters, devices with ultra-thin atomic layer deposited Al2O3 or TiO2 direct on top of perovskite showed good performance. However, thermal instability of devices still did not improve due to imperfect coverage of oxides layer resulted from lack of nucleation cite on perovskite surface. To solve this problem, we deposited ALD AZO on organic charge transport layer instead. Device of this architecture reached efficiency of 14.6%, and only dropped to 80% of initial value after 1-day storage in glove box at 85℃. The thermal instability was much improved as efficiency of control devices dropped to less than 50% of initial value.