| 摘要: | 錫鈣鈦礦太陽能電池(Tin Perovskite solar cells, TPSC)由於其吸收層的毒性低、能隙小(Eg 1.41 eV)與吸收係數高等優點，且光伏表現佳而受重視。然而，錫鈣鈦礦(Tin Perovskite, T-Psk)層中的Sn2+容易與空氣中的水氣及氧氣反應氧化成Sn4+，且T-Psk膜的結晶速度快，不易形成緻密的膜，導致所組裝之元件的效率及長時間穩定性差。本研究探討於FA0.98EDA0.01SnI3前驅溶液中添加三種弱酸性離子性富勒烯衍生物C60-(RT2+)6(12X-) (X = Cl, Br, I) (簡稱6-X (X = Cl, Br, I))製備體異質介面的T-Psk膜(稱為6-X@FA0.98EDA0.01SnI3膜)，其中以6-Br@FA0.98EDA0.01SnI3膜作為吸收層所組裝之元件的光電轉換效率達10.09%比以FA0.98EDA0.01SnI3膜作為吸收層所組裝之元件的光電轉換效率(8.21%)高約20%。在未封裝的條件下，以6-Br@FA0.98EDA0.01SnI3膜作為吸收層的TPSC元件放置在手套箱中2520小時後光電轉換效率仍可維持原來效率的84%；而以FA0.98EDA0.01SnI3膜作為吸收層的TPSC元件之光電轉換效率僅剩原來效率的53%。添加6-Br可填補T-Psk膜的晶界，且有部份的Br-進入T-Psk膜的晶格中調整T-Psk層的前置軌域能階，減少載子傳遞至載子傳遞層所造成的能量損失，使所組裝之元件的Voc值由0.59 V增加至0.62 V。此外，添加6-Br也能延緩T-Psk膜的結晶速度，使所製備之T-Psk膜的顆粒大、平整、緻密且結晶度高。而添加6-Br可增加T-Psk前驅溶液的酸性，因此T-Psk前驅溶液中的Sn2+不易氧化成Sn4+，故6-Br@FA0.98EDA0.01SnI3膜的Sn2+/Sn4+比例比FA0.98EDA0.01SnI3膜高。;Tin Perovskite solar cells (TPSC) are the topic under extensive studies due to the absorber has low toxicity, small energy gap (Eg 1.41 eV) and high absorption coefficient as well as the cell has good photovoltaic performance. However, Sn2+ in the Tin Perovskite (T-Psk) easily reacts with moisture and oxygen in the air to be oxidized to Sn4+ easily as well as the crystallization rate of the T-Psk film is very fast thus it is difficult to form a dense and smooth T-Psk film, resulting in poor efficiency and long-term stability of the device. This study explores the effect of adding three weakly acidic ionic fullerene derivatives C60-(RT2+)6(12X-) (X = Cl, Br, I) (named 6-X (X = Cl, Br, I)) in T-Psk to prepare bulk-heterojunction film (named 6-X@FA0.98EDA0.01SnI3 film). The power conversion efficiency (PCE) of the cell based on 6-Br@FA0.98EDA0.01SnI3 film achieves the highest of 10.09% which is about 20% higher than the that (8.21%) of the device using FA0.98EDA0.01SnI3 film as the absorption layer. Without encapsulation, TPSC with 6-Br@FA0.98EDA0.01SnI3 as the absorber maintains 84% of the initial efficiency when it was placed in the glove box for 2520 hours. While the PCE of the TPSC with FA0.98EDA0.01SnI3 absorber lost 47% of the original efficiency. 6-Br can fill the grain boundaries of the T-Psk film, and some Br- ions can enter the lattice of the T-Psk film to adjust to energy level to reduce the energy loss caused by the transfer of carriers to the carrier transport layer. As a result the Voc of the device increased from 0.59 V to 0.62 V. In addition, the addition of 6-Br can also slow the crystallization of the T-Psk film, so that 6-Br@FA0.98EDA0.01SnI3 film has large grain size, flat, dense and high crystallinity. 6-Br can also increase the acidity of the T-Psk precursor solution to stabilize Sn2+. Therefore, the Sn2+/Sn4+ ratio of the 6-Br@FA0.98EDA0.01SnI3 film is higher than that of FA0.98EDA0.01SnI3 film. |
