Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Science. 2019 Aug 2;365(6452):473-478. doi: 10.1126/science.aax3294.
We show that converting the surfaces of lead halide perovskite to water-insoluble lead (II) oxysalt through reaction with sulfate or phosphate ions can effectively stabilize the perovskite surface and bulk material. These capping lead oxysalt thin layers enhance the water resistance of the perovskite films by forming strong chemical bonds. The wide-bandgap lead oxysalt layers also reduce the defect density on the perovskite surfaces by passivating undercoordinated surface lead centers, which are defect-nucleating sites. Formation of the lead oxysalt layer increases the carrier recombination lifetime and boosts the efficiency of the solar cells to 21.1%. Encapsulated devices stabilized by the lead oxysalt layers maintain 96.8% of their initial efficiency after operation at maximum power point under simulated air mass (AM) 1.5 G irradiation for 1200 hours at 65°C.
我们表明，通过与硫酸盐或磷酸盐离子反应将卤化铅钙钛矿的表面转化为不溶于水的铅（II） 氧化物盐，可以有效地稳定钙钛矿的表面和体材料。这些覆盖的铅氧盐薄层通过形成强化学键来提高钙钛矿薄膜的耐水性。宽带隙铅氧盐层还通过钝化配位不足的表面铅中心（缺陷成核位点）来降低钙钛矿表面的缺陷密度。铅氧盐层的形成增加了载流子复合寿命，并将太阳能电池的效率提高到 21.1%。用铅氧盐层稳定的封装器件在 65°C 下，在模拟空气质量 (AM) 1.5 G 辐照下以最大功率点运行 1200 小时后，仍保持初始效率的 96.8%。
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