Ray Aniruddha, Martín-García Beatriz, Moliterni Anna, Casati Nicola, Boopathi Karunakara Moorthy, Spirito Davide, Goldoni Luca, Prato Mirko, Giacobbe Carlotta, Giannini Cinzia, Di Stasio Francesco, Krahne Roman, Manna Liberato, Abdelhady Ahmed L
Istituto Italiano di Tecnologia, Via Morego 30, Genoa, 16163, Italy.
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31, Genoa, 16146, Italy.
Adv Mater. 2022 Feb;34(7):e2106160. doi: 10.1002/adma.202106160. Epub 2022 Jan 10.
The solvent acidolysis crystallization technique is utilized to grow mixed dimethylammonium/methylammonium lead tribromide (DMA/MAPbBr ) crystals reaching the highest dimethylammonium incorporation of 44% while maintaining the 3D cubic perovskite phase. These mixed perovskite crystals show suppression of the orthorhombic phase and a lower tetragonal-to-cubic phase-transition temperature compared to MAPbBr . A distinct behavior is observed in the temperature-dependent photoluminescence properties of MAPbBr and mixed DMA/MAPbBr crystals due to the different organic cation dynamics governing the phase transition(s). Furthermore, lateral photodetectors based on these crystals show that, at room temperature, the mixed crystals possess higher detectivity compared to MAPbBr crystals caused by structural compression and reduced surface trap density. Remarkably, the mixed-crystal devices exhibit large enhancement in their detectivity below the phase-transition temperature (at 200 K), while for the MAPbBr devices only insignificant changes are observed. The high detectivity of the mixed crystals makes them attractive for visible-light communication and for space applications. The results highlight the importance of the synthetic technique for compositional engineering of halide perovskites that governs their structural and optoelectronic properties.
采用溶剂酸解结晶技术生长混合二甲基铵/甲基铵三溴化铅（DMA/MAPbBr₃）晶体，在保持三维立方钙钛矿相的同时，二甲基铵掺入量最高可达44%。与MAPbBr₃相比，这些混合钙钛矿晶体显示出正交相的抑制以及较低的四方相到立方相的转变温度。由于控制相变的有机阳离子动力学不同，在MAPbBr₃和混合DMA/MAPbBr₃晶体的温度依赖光致发光特性中观察到明显不同的行为。此外，基于这些晶体的横向光电探测器表明，在室温下，由于结构压缩和表面陷阱密度降低，混合晶体比MAPbBr₃晶体具有更高的探测率。值得注意的是，混合晶体器件在低于相变温度（200K）时探测率大幅提高，而对于MAPbBr₃器件，仅观察到微不足道的变化。混合晶体的高探测率使其在可见光通信和空间应用中具有吸引力。这些结果突出了合成技术对卤化物钙钛矿成分工程的重要性，该技术决定了它们的结构和光电性能。
