Wang Zeyu, Rong Xiang, Wang Luyao, Wang Wei, Lin Hong, Li Xin
Pen-Tung Sah Institute of Micro-Nano Science and Technology , Xiamen University , Xiamen 361005 , China.
State Key Laboratory of New Ceramics & Fine Processing, School of Material Science and Engineering , Tsinghua University , Beijing 100084 , China.
ACS Appl Mater Interfaces. 2020 Feb 19;12(7):8342-8350. doi: 10.1021/acsami.9b22471. Epub 2020 Feb 10.
NiO has been widely used as an effective hole-transport material for inverted perovskite solar cells (PSCs), particularly flexible PSCs, owing to its low-temperature processing, low cost, and good electron-blocking ability. However, the band structure alignment between low-temperature-processed NiO and the perovskite layer is not satisfactory, resulting in reduced photovoltaic performance. Herein, we report a novel strategy to tune the NiO hole-transport layer for achieving high-performance flexible PSCs. Amino-functionalized graphene quantum dots (AGQDs) are employed in the NiO film as a dual-role additive. On the one hand, the added AGQDs can provide abundant N atoms at the modified NiO layer surface to enhance the crystallization of the perovskite film by a Lewis base-acid interaction. On the other hand, the AGQDs can optimize the band structure alignment between the NiO and perovskite layers, facilitating hole extraction at the NiO/perovskite interface. As a result, the inverted flexible PSCs exhibit a high efficiency of 18.10%, which is comparable to the values reported for the current state-of-the-art inverted flexible PSCs. In addition to good air stability, our best flexible devices have excellent mechanical stability, retaining 88% of their initial efficiency after continuously bending 1000 times. This new strategy highlights a promising way to enhance the performance of inverted flexible PSCs.
由于低温处理、低成本和良好的电子阻挡能力，氧化镍已被广泛用作倒置钙钛矿太阳能电池（PSC），特别是柔性PSC的有效空穴传输材料。然而，低温处理的氧化镍与钙钛矿层之间的能带结构匹配并不理想，导致光伏性能下降。在此，我们报告了一种调整氧化镍空穴传输层以实现高性能柔性PSC的新策略。氨基功能化的石墨烯量子点（AGQD）被用作氧化镍薄膜中的双功能添加剂。一方面，添加AGQD可以在改性氧化镍层表面提供丰富的氮原子，通过路易斯酸碱相互作用增强钙钛矿薄膜的结晶。另一方面，AGQD可以优化氧化镍和钙钛矿层之间的能带结构匹配，促进在氧化镍/钙钛矿界面的空穴提取。结果，倒置柔性PSC表现出18.10%的高效率，这与当前最先进的倒置柔性PSC报道的值相当。除了良好的空气稳定性外，我们最好的柔性器件还具有出色的机械稳定性，在连续弯曲1000次后仍保持其初始效率的88%。这种新策略突出了一种提高倒置柔性PSC性能的有前途的方法。
