Interfacial Molecular Doping of Metal Halide Perovskites for Highly Efficient Solar Cells
Interfacial Molecular Doping of Metal Halide Perovskites for Highly Efficient Solar Cells
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DOI：
10.1002/adma.202001581
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发表时间：
2020-06-25
影响因子：
29.4
通讯作者：
Huang, Jinsong
中科院分区：
文献类型：
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作者：
Jiang, Qi;Ni, Zhenyi;Huang, Jinsong
在异质结太阳能电池中调整半导体掺杂在提高多种无机太阳能电池性能方面取得了巨大成功，而在钙钛矿太阳能电池中，由于钙钛矿掺杂难以可控，因此具有挑战性。在这里，一个4,4 ',4 ''-（吡嗪-2,3,5,6-四基）四基斯（N，N-双（4-甲氧基苯基）苯胺）（PT-TPA）的小分子可以有效地p-掺杂FA(x)MA(1-)(x)PbI(3)(FA: HC(NH2)(2)；报道了MA: CH3NH3)钙钛矿薄膜。PT-TPA分子间电荷转移特性形成稳定的共振结构，接受来自钙钛矿的电子。掺杂效应使钙钛矿暗电导率和载流子浓度提高了4737倍。计算表明，钙钛矿中八面体笼的前两层电子被转移到PT-TPA上。将PT-TPA应用于钙钛矿太阳能电池后，钙钛矿中掺杂诱导的能带弯曲有效地促进了空穴向空穴传输层的提取，并将电子向阴极侧排出，从而减少了阴极侧的电荷复合。优化后的器件光电压从1.12 V提高到1.17 V，光电流扫描效率为23.4%，稳定效率为22.9%。研究结果表明，分子掺杂是控制钙钛矿太阳能电池界面电荷重组的有效途径，与广泛应用的缺陷钝化技术是互补的。
Tailoring the doping of semiconductors in heterojunction solar cells shows tremendous success in enhancing the performance of many types of inorganic solar cells, while it is found challenging in perovskite solar cells because of the difficulty in doping perovskites in a controllable way. Here, a small molecule of 4,4 ',4 '',4 '''-(pyrazine-2,3,5,6-tetrayl) tetrakis (N,N-bis(4-methoxyphenyl) aniline) (PT-TPA) which can effectively p-dope the surface of FA(x)MA(1-)(x)PbI(3)(FA: HC(NH2)(2); MA: CH3NH3) perovskite films is reported. The intermolecular charge transfer property of PT-TPA forms a stabilized resonance structure to accept electrons from perovskites. The doping effect increases perovskite dark conductivity and carrier concentration by up to 4737 times. Computation shows that electrons in the first two layers of octahedral cages in perovskites are transferred to PT-TPA. After applying PT-TPA into perovskite solar cells, the doping-induced band bending in perovskite effectively facilitates hole extraction to hole transport layer and expels electrons toward cathode side, which reduces the charge recombination there. The optimized devices demonstrate an increased photovoltage from 1.12 to 1.17 V and an efficiency of 23.4% from photocurrent scanning with a stabilized efficiency of 22.9%. The findings demonstrate that molecular doping is an effective route to control the interfacial charge recombination in perovskite solar cells which is in complimentary to broadly applied defect passivation techniques.