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dc.contributor.authorRaissi, Mahfoudh
dc.contributor.authorSajjad, Muhammad Tariq
dc.contributor.authorPellegrin, Yann
dc.contributor.authorRoland, Thomas Jean
dc.contributor.authorJobic, Stephane
dc.contributor.authorBoujtita, Mohammed
dc.contributor.authorRuseckas, Arvydas
dc.contributor.authorSamuel, Ifor D. W.
dc.contributor.authorOdobel, Fabrice
dc.identifier.citationRaissi , M , Sajjad , M T , Pellegrin , Y , Roland , T J , Jobic , S , Boujtita , M , Ruseckas , A , Samuel , I D W & Odobel , F 2017 , ' Size dependence of efficiency of PbS quantum dots in NiO-based dye sensitised solar cells and mechanistic charge transfer investigation ' , Nanoscale , vol. 9 , no. 40 , pp. 15566-15575 .
dc.identifier.otherBibtex: urn:530e16d882c3b6e5cd2522f028cd4cd8
dc.identifier.otherORCID: /0000-0001-9114-3522/work/37255569
dc.descriptionANR is gratefully acknowledged for the financial support of these researches through the QuePhelec project (n° ANR-13-BS10-0011-01). Région des Pays de la Loire and Nantes University for the project LUMOMAT are also acknowledged. We acknowledge support from the European Research Council (grant number 321305) and the EPSRC (grant number EP/L017008/1). IDWS is a Royal Society Wolfson Research Merit award holder. The research data supporting this publication can be accessed at
dc.description.abstractQuantum dots (QDs) are very attractive materials for solar cells due to their high absorption coefficients, size dependence and easy tunability of their optical and electronic properties due to quantum confinement. Particularly interesting are the PbS QDs owing to their broad spectral absorption until the long wavelengths, their easy processability and low cost. Here, we used control of the PbS QDs size to understand charge transfer processes at the interfaces of NiO semiconductor and explain the optimal QDs size in photovoltaic devices. Towards this goal, we have synthesized a series of PbS QDs with different diameters (2.8 A until 4A) and investigated charge transfer dynamics by time resolved spectroscopy and their ability to act as sensitizers in nanocrystalline NiO based solar cells using the cobalt tris(4,4'-diterbutyl-2,2'-bipyridine) complex as redox mediator. We found that PbS QDs with average diameter of 3.0 nm are optimal size in terms of efficient charge transfers and light harvesting efficiency for photovoltaic performances. Our study showed that an hole injection from PbS QDs to NiO valence band (VB) is an efficient process even with low injection driving force (0.3 eV) and occurs in 6-10 ns. Furthermore we found that the direct electrolyte reduction (photoinduced electron transfer to the cobalt redox mediator) also occurs in parallel to the hole injection with rate constant of similar magnitude (10-20 ns). In spite of its large driving force, the rate constant of the oxidative quenching of PbS by Co(III) diminishes more steeply than hole injection on NiO when the diameter of PbS increases. This is understood as the consequence of increasing the trap states that limit electron shift. We believe that our detailed findings will advance the future design of QD sensitized photocathodes.
dc.subjectQC Physicsen
dc.subjectTK Electrical engineering. Electronics Nuclear engineeringen
dc.subjectSDG 7 - Affordable and Clean Energyen
dc.titleSize dependence of efficiency of PbS quantum dots in NiO-based dye sensitised solar cells and mechanistic charge transfer investigationen
dc.typeJournal articleen
dc.contributor.sponsorEuropean Research Councilen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.contributor.institutionUniversity of St Andrews. Condensed Matter Physicsen
dc.description.statusPeer revieweden

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