The power conversion efficiency of perovskite solar cells (PSCs) has ascended from 3.8% to 22.1% in recent years. ZnO has been well‐documented as an excellent electron‐transport material. However, the poor chemical compatibility between ZnO and organo‐metal halide perovskite makes it highly challenging to obtain highly efficient and stable PSCs using ZnO as the electron‐transport layer. It is demonstrated in this work that the surface passivation of ZnO by a thin layer of MgO and protonated ethanolamine (EA) readily makes ZnO as a very promising electron‐transporting material for creating hysteresis‐free, efficient, and stable PSCs. Systematic studies in this work reveal several important roles of the modification: (i) MgO inhibits the interfacial charge recombination, and thus enhances cell performance and stability; (ii) the protonated EA promotes the effective electron transport from perovskite to ZnO, further fully eliminating PSCs hysteresis; (iii) the modification makes ZnO compatible with perovskite, nicely resolving the instability of ZnO/perovskite interface. With all these findings, PSCs with the best efficiency up to 21.1% and no hysteresis are successfully fabricated. PSCs stable in air for more than 300 h are achieved when graphene is used to further encapsulate the cells.

中文翻译：

---

ZnO作为电子传输层的高效，无磁滞且稳定的钙钛矿太阳能电池：表面钝化的影响

近年来，钙钛矿太阳能电池（PSC）的功率转换效率从3.8％上升到22.1％。ZnO已被证明是一种出色的电子传输材料。但是，ZnO和有机金属卤化物钙钛矿之间的化学相容性差，因此使用ZnO作为电子传输层来获得高效，稳定的PSC极具挑战性。这项工作表明，MgO和质子化乙醇胺（EA）的薄层对ZnO的表面钝化，很容易使ZnO成为非常有希望的电子传输材料，以产生无滞后，高效且稳定的PSC。这项工作的系统研究揭示了修饰的几个重要作用：（i）MgO抑制界面电荷的重组，从而增强细胞的性能和稳定性；（ii）质子化的EA促进了电子从钙钛矿到ZnO的有效传输，从而进一步完全消除了PSC的滞后现象；（iii）改性使ZnO与钙钛矿相容，很好地解决了ZnO /钙钛矿界面的不稳定性。基于所有这些发现，成功制造了效率最高可达21.1％且无滞后的PSC。当使用石墨烯进一步封装细胞时，可获得在空气中稳定超过300小时的PSC。