Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

Citation

Kim JY, Adinolfi V, Sutherland BR, Voznyy O, Kwon SJ, et al. (2015) Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films. Nat Comms 6: 7772. Available: http://dx.doi.org/10.1038/ncomms8772.

Sponsors

This publication is based in part on work supported by Award KUS-11-009-21, made by King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. This work was supported by the Korean Government through the New and Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by MOTIE (No.20133030011320) and by KIST through Institutional Project (2E25411). This work was supported by IBS-R004-G2. J.Y.K. extends appreciation for an NSERC Banting postdoctoral fellowship. We thank E. Palmiano, L. Levina, R. Wolowiec and D. Kopilovic for their help during the course of the study.

Publisher

Springer Nature

Journal

Nature Communications

ISSN

2041-1723

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