Liu Albert, Nagamine Gabriel, Bonato Luiz G, Almeida Diogo B, Zagonel Luiz F, Nogueira Ana F, Padilha Lazaro A, Cundiff Steven T
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States.
Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Campinas, Sao Paulo 13083-970, Brazil.
ACS Nano. 2021 Apr 27;15(4):6499-6506. doi: 10.1021/acsnano.0c09244. Epub 2021 Mar 26.
Perovskite nanoplatelets possess extremely narrow absorption and emission line widths, which are crucial characteristics for many optical applications. However, their underlying intrinsic and extrinsic line-broadening mechanisms are poorly understood. Here, we apply multidimensional coherent spectroscopy to determine the homogeneous line broadening of colloidal perovskite nanoplatelet ensembles. We demonstrate a dependence of not only their intrinsic line widths but also of various broadening mechanisms on platelet geometry. We find that decreasing nanoplatelet thickness by a single monolayer results in a 2-fold reduction of the inhomogeneous line width and a 3-fold reduction of the intrinsic homogeneous line width to the sub-millielectronvolts regime. In addition, our measurements suggest homogeneously broadened exciton resonances in two-layer (but not necessarily three-layer) nanoplatelets at room-temperature.
钙钛矿纳米片具有极窄的吸收和发射线宽，这是许多光学应用的关键特性。然而，其潜在的内在和外在线宽展宽机制却鲜为人知。在此，我们应用多维相干光谱来确定胶体钙钛矿纳米片集合体的均匀线宽展宽。我们证明，不仅它们的本征线宽，而且各种展宽机制都依赖于纳米片的几何形状。我们发现，将纳米片厚度减少一个单层会导致非均匀线宽降低两倍，本征均匀线宽降低三倍，达到亚毫电子伏特范围。此外，我们的测量表明，在室温下，两层（但不一定是三层）纳米片中的激子共振是均匀展宽的。
