Issue 9, 2014

Tailoring of the PbS/metal interface in colloidal quantum dot solar cells for improvements of performance and air stability

Abstract

Despite the outstanding advantages of a simple structure and cost-effectiveness of solution-based fabrication, Schottky junction quantum dot solar cells (QDSCs) often demonstrate low open-circuit voltage and power conversion efficiency (PCE) due to insufficient band bending at the QD/metal Schottky junction. Generally, this undesirable result stems from the presence of many defects at the QD/metal interface and the consequent Fermi-level pinning effect. Here, we show how the simple oxidation of PbS QDs at the PbS/metal interface can greatly improve the open-circuit voltage, fill factor, and PCE of Schottky junction QDSCs. On the basis of systematic analysis results using current–voltage characterization, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and light-soaking tests, we reveal that this enhancement originates from reduced interface states at the PbS/metal Schottky junction. Moreover, a significant enhancement of stability of the device is confirmed by the maintenance of >55% of its initial PCE even after 500 hours exposure in air without additional passivation.

Graphical abstract: Tailoring of the PbS/metal interface in colloidal quantum dot solar cells for improvements of performance and air stability

Supplementary files

Article information

Article type
Paper
Submitted
13 Feb 2014
Accepted
16 Jun 2014
First published
18 Jun 2014

Energy Environ. Sci., 2014,7, 3052-3060

Tailoring of the PbS/metal interface in colloidal quantum dot solar cells for improvements of performance and air stability

M. Choi, J. Oh, J. Yoo, J. Choi, D. M. Sim and Y. S. Jung, Energy Environ. Sci., 2014, 7, 3052 DOI: 10.1039/C4EE00502C

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