Janker Lisa, Tong Yu, Polavarapu Lakshminarayana, Feldmann Jochen, Urban Alexander S, Krenner Hubert J
Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies , Universität Augsburg , Universitätsstr. 1 , 86179 Augsburg , Germany.
Nanosystems Initiative Munich (NIM) , Schellingstr. 4 , 80339 Munich , Germany.
Nano Lett. 2019 Dec 11;19(12):8701-8707. doi: 10.1021/acs.nanolett.9b03396. Epub 2019 Nov 5.
For optoelectronic devices, high transport mobilities of electrons and holes are desirable, which, moreover, should be close to identical. Acousto-optoelectric spectroscopy is employed to probe the spatiotemporal dynamics of both electrons and holes inside CsPbI nanowires. These dynamics are induced without the need for electrical contacts simply by the piezoelectric field of a surface acoustic wave. Its radio frequency of = 324 MHz natively avoids spurious contributions from ion migration typically occurring in these materials. The observed dynamic modulation of the photoluminescence is faithfully reproduced by solving the drift and diffusion currents of electrons and holes induced by the surface acoustic wave. These calculations confirm that the mobilities of electrons and holes are equal and quantify them to be μ = μ = 3 ± 1 cm V s. Additionally, carrier loss due to surface recombination is shown to be largely suppressed in CsPbI nanowires. Both findings mark significant advantages over traditional compound semiconductors, in particular, GaAs, for applications in future optoelectronic and photovoltaic devices. The demonstrated sublifetime modulation of the optical emission may find direct application in switchable perovskite light-emitting devices employing mature surface acoustic wave technology.
对于光电器件而言，电子和空穴具有高迁移率是理想的，而且两者的迁移率应接近相同。采用声光电光光谱法来探测CsPbI纳米线内部电子和空穴的时空动力学。这些动力学是由表面声波的压电场诱导产生的，无需电接触。其324 MHz的射频天然地避免了这些材料中通常出现的离子迁移带来的虚假影响。通过求解表面声波诱导的电子和空穴的漂移电流和扩散电流，能如实地再现所观察到的光致发光的动态调制。这些计算证实电子和空穴的迁移率相等，并将其量化为μ = μ = 3 ± 1 cm² V⁻¹ s⁻¹。此外，在CsPbI纳米线中，表面复合导致的载流子损失被证明在很大程度上受到抑制。这两个发现标志着相对于传统化合物半导体，特别是GaAs，在未来光电器件和光伏器件应用中具有显著优势。所展示的光发射亚寿命调制可能会在采用成熟表面声波技术的可切换钙钛矿发光器件中找到直接应用。
