The Division of Chemical Physics and NanoLund, Lund University, Box 124, 22100Lund, Sweden.
Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio43210, United States.
J Phys Chem Lett. 2023 Feb 2;14(4):1066-1072. doi: 10.1021/acs.jpclett.2c03389. Epub 2023 Jan 25.
Over the past two decades, intensive research efforts have been devoted to suppressions of Auger recombination in metal-chalcogenide and perovskite nanocrystals (PNCs) for the application of photovoltaics and light emitting devices (LEDs). Here, we have explored dodecahedron cesium lead bromide perovskite nanocrystals (DNCs), which show slower Auger recombination time compared to hexahedron nanocrystals (HNCs). We investigate many-body interactions that are manifested under high excitation flux density in both NCs using ultrafast spectroscopic pump-probe measurements. We demonstrate that the Auger recombination rate due to multiexciton recombinations are lower in DNCs than in HNCs. At low and intermediate excitation density, the majority of carriers recombine through biexcitonic recombination. However, at high excitation density (>10 cm) a higher number of many-body Auger process dominates over biexcitonic recombination. Compared to HNCs, high PLQY and slower Auger recombinations in DNCs are likely to be significant for the fabrication of highly efficient perovskite-based photonics and LEDs.
在过去的二十年中，人们投入了大量的研究精力来抑制金属-硫属化物和钙钛矿纳米晶体（PNCs）中的俄歇复合，以应用于光伏和发光器件（LEDs）。在这里，我们研究了十二面体铯铅溴钙钛矿纳米晶体（DNCs），与六面体纳米晶体（HNCs）相比，它显示出较慢的俄歇复合时间。我们使用超快光谱泵浦探针测量研究了在高激发通量密度下两种 NCs 中表现出的多体相互作用。我们证明，由于多激子复合，DNCs 中的俄歇复合速率低于 HNCs。在低激发密度和中等激发密度下，大多数载流子通过双激子复合进行复合。然而，在高激发密度（>10 cm）下，更多的多体俄歇过程主导双激子复合。与 HNCs 相比，DNCs 中较高的 PLQY 和较慢的俄歇复合可能对制造高效的基于钙钛矿的光子学和 LEDs 具有重要意义。
