The effects of doping with alkali metals and formamidinium cations on CH₃NH₃(Rb)Pb(Cu)I₃(Cl,Br) perovskite photovoltaic cells were investigated. Lattice constants were slightly decreased and increased by K and Na doping, respectively. This indicated that Na atoms occupied interstitial sites in the perovskite crystal. The conversion efficiencies for most of the devices decreased after one year. However, the conversion efficiency for the CH₃NH₃(Na,Rb)Pb(Cu)I₃(Cl,Br) photovoltaic cell was unchanged after one year. The Na-doped perovskite provided the smallest carrier trap density, which suggested that lattice defects were suppressed by Na doping. First principles calculations supported these experimental results.

中文翻译：

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掺杂Na，K，Rb和甲ami阳离子对（CH3NH3）0.99Rb0.01Pb0.99Cu0.01I3-x（Cl，Br）x钙钛矿型光伏电池的影响

研究了碱金属和甲ami阳离子对CH ₃ NH ₃（Rb）Pb（Cu）I ₃（Cl，Br）钙钛矿型光伏电池的影响。钾和钠掺杂分别使晶格常数略有降低和增加。这表明Na原子占据了钙钛矿晶体中的间隙位置。一年后，大多数设备的转换效率都下降了。但是，CH ₃ NH ₃（Na，Rb）Pb（Cu）I ₃的转化效率一年后，（Cl，Br）光伏电池未发生变化。Na掺杂的钙钛矿提供最小的载流子陷阱密度，这表明Na掺杂抑制了晶格缺陷。第一性原理的计算支持了这些实验结果。