Iodine chemistry determines the defect tolerance of lead-halide perovskites†,Energy & Environmental Science

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Iodine chemistry determines the defect tolerance of lead-halide perovskites†
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2018-02-09 00:00:00 , DOI: 10.1039/c8ee00124c
Daniele Meggiolaro _{1,

2,

3,

4,

5} , Silvia G. Motti _{4,

6,

7,

8,

9} , Edoardo Mosconi _{1,

2,

3,

4,

5} , Alex J. Barker _{4,

6,

7,

8} , James Ball _{4,

6,

7,

8} , Carlo Andrea Riccardo Perini _{4,

6,

7,

8} , Felix Deschler _{10,

11,

12,

13} , Annamaria Petrozza _{4,

6,

7,

8} , Filippo De Angelis _{1,

2,

3,

4,

5}

Affiliation

Metal-halide perovskites are outstanding materials for photovoltaics. Their long carrier lifetimes and diffusion lengths favor efficient charge collection, leading to efficiencies competing with established photovoltaics. These observations suggest an apparently low density of traps in the prototype methylammonium lead iodide (MAPbI₃) contrary to the expected high defect density of a low-temperature, solution-processed material. Combining first-principles calculations and spectroscopic measurements we identify less abundant iodine defects as the source of photochemically active deep electron and hole traps in MAPbI₃. The peculiar iodine redox chemistry leads, however, to kinetic deactivation of filled electron traps, leaving only short-living hole traps as potentially harmful defects. Under mild oxidizing conditions the amphoteric hole traps can be converted into kinetically inactive electron traps, providing a rationale for the defect tolerance of metal-halide perovskites. Bromine and chlorine doping of MAPbI₃ also inactivate hole traps, possibly explaining the superior optoelectronic properties of mixed-halide perovskites.

中文翻译：

碘化学决定了卤化钙钛矿的缺陷耐受性†

金属卤化物钙钛矿是用于光伏的杰出材料。它们的较长的载流子寿命和扩散长度有利于有效的电荷收集，从而提高了与现有光伏电池竞争的效率。这些观察结果表明，在原型甲基铵碘化铅（MAPbI ₃）中陷阱的表观密度很低，这与低温固溶处理材料的预期高缺陷密度相反。结合第一性原理计算和光谱测量，我们确定了碘丰度较差的碘是MAPbI _3中具有光化学活性的深电子和空穴陷阱的来源。然而，独特的碘氧化还原化学作用导致填充电子陷阱的动力学失活，仅留下短寿命的空穴陷阱作为潜在的有害缺陷。在温和的氧化条件下，两性空穴陷阱可以转化为动力学上不活泼的电子陷阱，从而为金属卤化物钙钛矿的缺陷耐受性提供了理论依据。MAPbI _3的溴和氯掺杂也使空穴阱失活，这可能解释了混合卤化物钙钛矿的优异光电性能。

更新日期：2018-02-09

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