Zanetta Andrea, Larini Valentina, Toniolo Francesco, Vishal Badri, Elmestekawy Karim A, Du Jiaxing, Scardina Alice, Faini Fabiola, Pica Giovanni, Pirota Valentina, Pitaro Matteo, Marras Sergio, Ding Changzeng, Yildirim Bumin K, Babics Maxime, Ugur Esma, Aydin Erkan, Ma Chang-Qi, Doria Filippo, Loi Maria Antonietta, De Bastiani Michele, Herz Laura M, Portale Giuseppe, De Wolf Stefaan, Islam M Saiful, Grancini Giulia
Università Degli Studi Di Pavia - Pavia (Italy), Department of Chemistry & INSTM, Via T. Taramelli 14, Pavia, Italy.
Department of Materials, University of Oxford, Oxford, UK.
Nat Commun. 2024 Oct 21;15(1):9069. doi: 10.1038/s41467-024-53339-6.
Controlling crystal growth alignment in low-dimensional perovskites (LDPs) for solar cells has been a persistent challenge, especially for low-n LDPs (n < 3, n is the number of octahedral sheets) with wide band gaps (>1.7 eV) impeding charge flow. Here we overcome such transport limits by inducing vertical crystal growth through the addition of chlorine to the precursor solution. In contrast to 3D halide perovskites (APbX), we find that Cl substitutes I in the equatorial position of the unit cell, inducing a vertical strain in the perovskite octahedra, and is critical for initiating vertical growth. Atomistic modelling demonstrates the thermodynamic stability and miscibility of Cl/I structures indicating the preferential arrangement for Cl-incorporation at I-sites. Vertical alignment persists at the solar cell level, giving rise to a record 9.4% power conversion efficiency with a 1.4 V open circuit voltage, the highest reported for a 2 eV wide band gap device. This study demonstrates an atomic-level understanding of crystal tunability in low-n LDPs and unlocks new device possibilities for smart solar facades and indoor energy generation.
控制用于太阳能电池的低维钙钛矿（LDPs）中的晶体生长取向一直是一项长期挑战，特别是对于宽带隙（>1.7 eV）阻碍电荷流动的低n值LDPs（n < 3，n为八面体层数）而言。在此，我们通过向前驱体溶液中添加氯来诱导垂直晶体生长，从而克服了此类传输限制。与三维卤化物钙钛矿（APbX）不同，我们发现Cl在晶胞的赤道位置取代I，在钙钛矿八面体中诱导垂直应变，并且对于启动垂直生长至关重要。原子模型表明Cl/I结构的热力学稳定性和混溶性，表明Cl在I位点掺入的优先排列。垂直取向在太阳能电池层面得以保持，产生了创纪录的9.4%的功率转换效率以及1.4 V的开路电压，这是2 eV宽带隙器件所报道的最高值。这项研究展示了对低n值LDPs中晶体可调性的原子级理解，并为智能太阳能外墙和室内能量产生开启了新的器件可能性。
