Affiliation:
1. School of Advanced Materials and Nanotechnology Xidian University Xi'an 710126 P. R. China
2. Institut National de la Recherche Scientifique Centre Énergie Matériaux Télécommunications 1650 Boulevard Lionel‐Boulet Varennes Québec J3X 1P7 Canada
3. CINBIO Universidade de Vigo Vigo 36310 Spain
4. Department of Engineering Faculty of Agriculture Dalhousie University Truro NS B2N 5E3 Canada
Abstract
AbstractSemiconductor core/shell quantum dots (QDs) are considered promising building blocks to fabricate photoelectrochemical (PEC) cells for the direct conversion of solar energy into hydrogen (H2). However, the lattice mismatch between core and shell in such QDs results in undesirable defects and severe carrier recombination, limiting photo‐induced carrier separation/transfer and solar‐to‐fuel conversion efficiency. Here, an interface engineering approach is explored to minimize the core‐shell lattice mismatch in CdS/CdSexS1‐x (x = 0.09–1) core/shell QDs (g‐CSG). As a proof‐of‐concept, PEC cells based on g‐CSG QDs yield a remarkable photocurrent density of 13.1 mA cm−2 under AM 1.5 G one‐sun illumination (100 mW cm−2), which is ≈54.1% and ≈33.7% higher compared to that in CdS/CdSe0.5S0.5 (g‐CSA) and CdS/CdSe QDs (g‐CS), respectively. Theoretical calculations and carrier dynamics confirm more efficient carrier separation and charge transfer rate in g‐CSG QDs with respect to g‐CSA and g‐CS QDs. These results are attributed to the minimization of the core‐shell lattice mismatch by the cascade gradient shell in g‐CSG QDs, which modifies carrier confinement potential and reduces interfacial defects. This work provides fundamental insights into the interface engineering of core/shell QDs and may open up new avenues to boost the performance of PEC cells for H2 evolution and other QDs‐based optoelectronic devices.
Funder
Canada Foundation for Innovation
Canada Research Chairs
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry
Cited by
2 articles.
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