论文标题
从茎 - 蜂物中测量的原骨薄铅卤化物钙钛矿（CSPBBR3）纳米片中的带隙
Bandgap in orthorhombic thin lead halide perovskite (CsPbBr3) nanosheets measured from STEM-EELS
论文作者
论文摘要
无机铅卤化物钙钛矿由于其带隙可调性，高光致发光量子产率和狭窄的发射线宽度，因此是光电应用的有前途的候选。特别是，它们提供了改变带隙的可能性，这是纳米级晶体的卤化物组成和尺寸/形状的函数。在这里，我们提出了经过像差校正的扫描透射显微镜（STEM）研究CSPBBR3的扩展纳米片，直接证明了它们的正交晶体结构及其用CS-BR平面的横向终止。来自单个纳米片的带隙通过单色电子能量损失光谱（EEL）测量。我们发现，从低于10 nm的厚度开始，带隙的增加，与在量子点中观察到的3D限制相比，纳米片中1D限制的效果较小，如密度功能理论计算和集合测量中的光学光谱数据所预测的那样。
Inorganic lead halide perovskites are promising candidates for optoelectronic applications, due to their bandgap tunability, high photoluminescence quantum yield, and narrow emission line widths. In particular, they offer the possibility to vary the bandgap as a function of the halide composition and dimension/shape of the crystals at the nanoscale. Here we present an aberration-corrected scanning transmission microscopy (STEM) study of extended nanosheets of CsPbBr3 directly demonstrating their orthorhombic crystal structure and their lateral termination with Cs-Br planes. The bandgaps from individual nanosheets are measured by monochromated electron energy loss spectroscopy (EELS). We find an increase of the bandgap starting at thicknesses below 10 nm, confirming the less dramatic effect of 1D confinement in nanosheets compared to the 3D confinement observed in quantum dots, as predicted by density functional theory calculations and optical spectroscopy data from ensemble measurements.
