Liu Yang, Sun Hao, Liao Feiyi, Li Gaocai, Zhao Chen, Cui Can, Mei Jun, Zhao Yiying
Institute of Materials, China Academy of Engineering Physics, Jiangyou, Sichuan 621908, China.
Chengdu Development Center of Science and Technology, China Academy of Engineering Physics, Chengdu, Sichuan 610000, China.
ACS Omega. 2021 Dec 7;6(50):34485-34493. doi: 10.1021/acsomega.1c04685. eCollection 2021 Dec 21.
Interfacial defects at the electron transport layer (ETL) and perovskite (PVK) interface are critical to the power conversion efficiency (PCE) and stabilities of the perovskite solar cells (PSCs) via significantly affecting the quality of both interface contacts and PVK layers. Here, we demonstrate a simple ionic bond passivation method, employing NaS solution treatment of the surface of titanium dioxide (TiO) layers, to effectively passivate the traps at the TiO/Cs(MAFA)Pb(BrI) PVK interface and enhance the performance of PSCs. X-ray photoelectron spectroscopy and other characterizations show that the NaS treatment introduced S ions at the TiO/PVK interface, where S ions effectively bridged the TiO ETL and the PVK layer via forming chemical bonds with Ti atoms and with uncoordinated Pb atoms and resulted in the reduced defect density and improved the crystallinity of PVK layers. In addition, the S ions can effectively enlarge the grain size of the PVK layers. The average PCE of solar cells is improved from 15.77 to 19.06% via employing the NaS-treated TiO layers. This work demonstrates a simple and facile interface passivation method using ionic bond passivation to afford high-performance PSCs. The bridging effect of S ions may inspire the further exploration of the ionic bond passivation and sulfur-based passivation materials.
电子传输层（ETL）与钙钛矿（PVK）界面处的界面缺陷对钙钛矿太阳能电池（PSC）的功率转换效率（PCE）和稳定性至关重要，因为它会显著影响界面接触和PVK层的质量。在此，我们展示了一种简单的离子键钝化方法，即采用硫化钠（NaS）溶液处理二氧化钛（TiO）层表面，以有效钝化TiO/Cs(MAFA)Pb(BrI) PVK界面处的陷阱并提高PSC的性能。X射线光电子能谱和其他表征表明，NaS处理在TiO/PVK界面引入了S离子，其中S离子通过与Ti原子以及未配位的Pb原子形成化学键，有效地连接了TiO ETL和PVK层，从而降低了缺陷密度并提高了PVK层的结晶度。此外，S离子可以有效增大PVK层的晶粒尺寸。通过使用经NaS处理的TiO层，太阳能电池的平均PCE从15.77%提高到了19.06%。这项工作展示了一种使用离子键钝化来制备高性能PSC的简单易行的界面钝化方法。S离子的桥接效应可能会激发对离子键钝化和硫基钝化材料的进一步探索。
