Wetting-Layer-Assisted Synthesis of Inverted CdSe/PbSe Quantum Dots and their Photophysical and Photo-Electrical Properties

Vladimir Sayevich; Whi Dong Kim; Zachary L. Robinson; Oleg V. Kozlov; Clément Livache; Namyoung Ahn; Heeyoung Jung; Victor I. Klimov

arXiv · 2412.17939

Wetting-Layer-Assisted Synthesis of Inverted CdSe/PbSe Quantum Dots and their Photophysical and Photo-Electrical Properties

Vladimir Sayevich·Whi Dong Kim·Zachary L. Robinson·Oleg V. Kozlov·Clément Livache·Namyoung Ahn·Heeyoung Jung·Victor I. Klimov

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Abstract

Heterostructured quantum dots (QDs) based on narrow-gap PbSe and wide-gap CdSe have been studied with an eye on their prospective applications in near-infrared (NIR) light sources, photodetectors, and solar cells. The most common structural motif is a spherical QD comprising a PbSe core enclosed into a CdSe shell. However, the potential barrier created by the CdSe shell complicates extraction of band-edge charge carriers from the QD. Therefore, conventional PbSe/CdSe QDs are not suitable for applications in practical photoconversion devices. Here we report inverted CdSe/PbSe core/shell QDs that overcome this drawback. In these structures, both photocarriers (electron and hole) exhibit a significant degree of shell localization and are therefore free to move within the QD solid and be extracted into an external circuit. To create such QDs, we employ a novel synthetic method in which a thin, atomically controlled wetting layer is used to homogenize the surface of the CdSe core and thus promote directionally uniform growth of the PbSe shell. Unlike noninverted QDs, inverted core/shell structures exhibit highly efficient photocarrier transport, making them excellent candidates for applications in practical photoconversion including photovoltaics, photodetection, and photochemistry.

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Vladimir Sayevich, Whi Dong Kim, Zachary L. Robinson, Oleg V. Kozlov, Clément Livache, Namyoung Ahn, Heeyoung Jung, Victor I. Klimov. 2024-12-23. Wetting-Layer-Assisted Synthesis of Inverted CdSe/PbSe Quantum Dots and their Photophysical and Photo-Electrical Properties. https://arxiv.org/abs/2412.17939

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