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Perovskite superlattices with efficient carrier dynamics
Nature ( IF 50.5 ) Pub Date : 2022-08-10 , DOI: 10.1038/s41586-022-04961-1
Yusheng Lei 1, 2 , Yuheng Li 1 , Chengchangfeng Lu 3 , Qizhang Yan 1 , Yilei Wu 2 , Finn Babbe 4 , Huaxin Gong 2 , Song Zhang 2 , Jiayun Zhou 5 , Ruotao Wang 1 , Ruiqi Zhang 1 , Yimu Chen 1 , Hsinhan Tsai 6 , Yue Gu 5 , Hongjie Hu 1 , Yu-Hwa Lo 3 , Wanyi Nie 6 , Taeyoon Lee 7, 8 , Jian Luo 1, 5 , Kesong Yang 1 , Kyung-In Jang 9 , Sheng Xu 1, 5, 6, 10
Affiliation  

Compared with their three-dimensional (3D) counterparts, low-dimensional metal halide perovskites (2D and quasi-2D; B2An−1MnX3n+1, such as B = R-NH3+, A = HC(NH2)2+, Cs+; M = Pb2+, Sn2+; X = Cl, Br, I) with periodic inorganic–organic structures have shown promising stability and hysteresis-free electrical performance1,2,3,4,5,6. However, their unique multiple-quantum-well structure limits the device efficiencies because of the grain boundaries and randomly oriented quantum wells in polycrystals7. In single crystals, the carrier transport through the thickness direction is hindered by the layered insulating organic spacers8. Furthermore, the strong quantum confinement from the organic spacers limits the generation and transport of free carriers9,10. Also, lead-free metal halide perovskites have been developed but their device performance is limited by their low crystallinity and structural instability11. Here we report a low-dimensional metal halide perovskite BA2MAn−1SnnI3n+1 (BA, butylammonium; MA, methylammonium; n = 1, 3, 5) superlattice by chemical epitaxy. The inorganic slabs are aligned vertical to the substrate and interconnected in a criss-cross 2D network parallel to the substrate, leading to efficient carrier transport in three dimensions. A lattice-mismatched substrate compresses the organic spacers, which weakens the quantum confinement. The performance of a superlattice solar cell has been certified under the quasi-steady state, showing a stable 12.36% photoelectric conversion efficiency. Moreover, an intraband exciton relaxation process may have yielded an unusually high open-circuit voltage (VOC).



中文翻译:

具有有效载流子动力学的钙钛矿超晶格

与它们的三维(3D)对应物相比,低维金属卤化物钙钛矿(2D和准2D;B 2 A n -1 M n X 3 n +1,例如B = R-NH 3 +,A =具有周期性无机-有机结构的HC(NH 2 ) 2 + , Cs + ; M = Pb 2+ , Sn 2+ ; X = Cl - , Br - , I - ) 具有良好的稳定性和无滞后的电气性能1, 2,3,4,5,6. 然而,由于多晶7中的晶界和随机取向的量子阱,它们独特的多量子阱结构限制了器件的效率。在单晶中,载流子沿厚度方向的传输受到层状绝缘有机间隔物8的阻碍。此外,有机间隔物的强量子限制限制了自由载流子9,10的产生和传输。此外,已开发出无铅金属卤化物钙钛矿,但其器件性能受到其低结晶度和结构不稳定性11的限制。在这里,我们报告了一种低维金属卤化物钙钛矿 BA 2 MA n -1 Sn nI 3 n +1 (BA, 丁基铵; MA, 甲基铵; n  = 1, 3, 5) 通过化学外延形成超晶格。无机板垂直于基板排列,并在平行于基板的纵横交错的二维网络中相互连接,从而在三个维度上实现高效的载流子传输。晶格不匹配的衬底压缩了有机间隔物,从而削弱了量子限制。超晶格太阳能电池在准稳态下的性能得到了验证,显示出稳定的12.36%的光电转换效率。此外,带内激子弛豫过程可能会产生异常高的开路电压 ( V OC )。

更新日期:2022-08-11
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