Dual emission in asymmetric giant PbS/CdS/CdS core/shell/shell quantum dots

Year: 2016

Authors: Zhao H., Sirigu G., Parisini A., Camellini A., Nicotra G., Rosei F., Morandi V., Zavelani-Rossi M., Vomiero A.

Autors Affiliation: CNR INO, SENSOR Lab, Via Branze 45, I-25123 Brescia, Italy; Inst Natl Rech Sci, 1650 Blvd Lionel Boulet, Varennes, PQ J3X 1S2, Canada; Politecn Milan, Dipartimento Fis, Piazza L da Vinci 32, I-20133 Milan, Italy; CNR IMM, Sez Bologna, Via Gobetti 101, I-40129 Bologna, Italy; CNR IMM, Sez Catania, Str VIII 5, I-95121 Catania, Italy; Univ Elect Sci & Technol China, Inst Fundamental & Frontier Sci, Chengdu 610054, Peoples R China; McGill Univ, Ctr Self Assembled Chem Struct, 801 Sherbrooke St West, Montreal, PQ H3A 0B8, Canada; Politecn Milan, IFN CNR, Dipartimento Energia, Via Ponzio 34-3, I-20133 Milan, Italy; Lulea Univ Technol, Dept Engn Sci & Math, S-97198 Lulea, Sweden.

Abstract: Semiconducting nanocrystals optically active in the infrared region of the electromagnetic spectrum enable exciting avenues in fundamental research and novel applications compatible with the infrared transparency windows of biosystems such as chemical and biological optical sensing, including nanoscale thermometry. In this context, quantum dots (QDs) with double color emission may represent ultra-accurate and self-calibrating nanosystems. We present the synthesis of giant core/shell/shell asymmetric QDs having a PbS/CdS zinc blende (Zb)/CdS wurtzite (Wz) structure with double color emission close to the near-infrared (NIR) region. We show that the double emission depends on the excitation condition and analyze the electron-hole distribution responsible for the independent and simultaneous radiative exciton recombination in the PbS core and in the CdS Wz shell, respectively. These results highlight the importance of the driving force leading to preferential crystal growth in asymmetric QDs, and provide a pathway for the rational control of the synthesis of double color emitting giant QDs, leading to the effective exploitation of visible/NIR transparency windows.

Journal/Review: NANOSCALE

Volume: 8 (7)      Pages from: 4217  to: 4226

More Information: F. R. acknowledges the FQRNT for funding through team projects and funding from MDEIE for an international collaboration grant in collaboration with the European Network WIROX. A. V. is thankful to the Kempe Foundation and the LTU Labbfond program for support for equipment, and to the European Union for partial salary support under contract no. 299490, MCIOF and for partial funding under contract no. 295216, IRSES. F. R. is grateful to NSERC for funding and partial salary support through an EWR Steacie Memorial Fellowship and the Alexander von Humboldt Foundation for a FW Bessel Award and Elsevier for a grant from Applied Surface Science. M. Z.-R. and G. S acknowledge financial support from Fondazione Cariplo through the project NANOCRYSLAS (grant no. 2012-0824); this work was performed in the context of the European COST Action MP1302 Nanospectroscopy.
KeyWords: Surface-related Emission; In-bulk Nanocrystals; Pbs Nanocrystals; Charge-transfer; Semiconductor Nanocrystals; Colloidal Nanocrystals; Auger Recombination; Suppressed Blinking; Infrared-emission; 2-color Quantum
DOI: 10.1039/c5nr08881j

ImpactFactor: 7.367
Citations: 47
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