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Imran, M.; Ramade, J.; Di Stasio, F.; De Franco, M.; Buha, J.; Van Aert, S.; Goldoni, L.; Lauciello, S.; Prato, M.; Infante, I.; Bals, S.; Manna, L. |
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Title ![sorted by Title field, ascending order (up)](img/sort_asc.gif) |
Alloy CsCdxPb1–xBr3Perovskite Nanocrystals: The Role of Surface Passivation in Preserving Composition and Blue Emission |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
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Volume |
32 |
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Pages |
acs.chemmater.0c03825 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Various strategies have been proposed to engineer the band gap of metal halide perovskite nanocrystals (NCs) while preserving their structure and composition and thus ensuring spectral stability of the emission color. An aspect that has only been marginally investigated is how the type of surface passivation influences the structural/color stability of AMX3 perovskite NCs composed of two different M2+ cations. Here, we report the synthesis of blue-emitting Cs-oleate capped CsCdxPb1–xBr3 NCs, which exhibit a cubic perovskite phase containing Cd-rich domains of Ruddlesden–Popper phases (RP phases). The RP domains spontaneously transform into pure orthorhombic perovskite ones upon NC aging, and the emission color of the NCs shifts from blue to green over days. On the other hand, postsynthesis ligand exchange with various Cs-carboxylate or ammonium bromide salts, right after NC synthesis, provides monocrystalline NCs with cubic phase, highlighting the metastability of RP domains. When NCs are treated with Cs-carboxylates (including Cs-oleate), most of the Cd2+ ions are expelled from NCs upon aging, and the NCs phase evolves from cubic to orthorhombic and their emission color changes from blue to green. Instead, when NCs are coated with ammonium bromides, the loss of Cd2+ ions is suppressed and the NCs tend to retain their blue emission (both in colloidal dispersions and in electroluminescent devices), as well as their cubic phase, over time. The improved compositional and structural stability in the latter cases is ascribed to the saturation of surface vacancies, which may act as channels for the expulsion of Cd2+ ions from NCs. |
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Wos |
000603288800034 |
Publication Date |
2020-12-04 |
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ISSN |
0897-4756 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.6 |
Times cited |
44 |
Open Access |
OpenAccess |
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Notes |
European Commission; Fonds Wetenschappelijk Onderzoek, G.0267.18N ; H2020 European Research Council, 770887 815128 851794 ; We acknowledge funding from the FLAG-ERA JTC2019 project PeroGas. S.B., and S.V.A. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grants #815128REALNANO and #770887PICOMETRICS) and from the Research Foundation Flanders (FWO, Belgium) through project funding G.0267.18N. F.D.S. acknowledges the funding from ERC starting grant NANOLED (851794). The computational work was carried out on the Dutch National e-infrastructure with the support of the SURF Cooperative; sygma |
Approved |
Most recent IF: 8.6; 2020 IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:174004 |
Serial |
6659 |
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Author |
Imran, M.; Peng, L.; Pianetti, A.; Pinchetti, V.; Ramade, J.; Zito, J.; Di Stasio, F.; Buha, J.; Toso, S.; Song, J.; Infante, I.; Bals, S.; Brovelli, S.; Manna, L. |
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Title ![sorted by Title field, ascending order (up)](img/sort_asc.gif) |
Halide perovskite-lead chalcohalide nanocrystal heterostructures |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Journal Of The American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
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Volume |
143 |
Issue |
3 |
Pages |
1435-1446 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We report the synthesis of colloidal CsPbX3-Pb4S3Br2 (X = Cl, Br, I) nanocrystal heterostructures, providing an example of a sharp and atomically resolved epitaxial interface between a metal halide perovskite and a non-perovskite lattice. The CsPbBr3-Pb4S3Br2 nanocrystals are prepared by a two-step direct synthesis using preformed subnanometer CsPbBr3 clusters. Density functional theory calculations indicate the creation of a quasi-type II alignment at the heterointerface as well as the formation of localized trap states, promoting ultrafast separation of photogenerated excitons and carrier trapping, as confirmed by spectroscopic experiments. Postsynthesis reaction with either Cl- or I- ions delivers the corresponding CsPbCI3-Pb4S3Br2 and CsPbI3-Pb4S3Br2 heterostructures, thus enabling anion exchange only in the perovskite domain. An increased structural rigidity is conferred to the perovskite lattice when it is interfaced with the chalcohalide lattice. This is attested by the improved stability of the metastable gamma phase (or “black” phase) of CsPbI3 in the CsPbI3-Pb4S3Br2 heterostructure. |
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Wos |
000614064400024 |
Publication Date |
2021-01-15 |
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ISSN |
0002-7863 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.858 |
Times cited |
54 |
Open Access |
OpenAccess |
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Notes |
This work was performed on the Dutch national e-infrastructure with the support of SURF Cooperative. L.P. and J.S. are thankful for the support by the National Key R&D Program of China (2018YFC0910600) and the National Natural Science Foundation of China (61775145). F.D.S. and S.B. acknowledge support by the European Research Council via the ERC-StG “NANOLED” (851794) and the ERC-Cog “REALNANO” (815128). The authors acknowledge financial support from the European Commission under the Horizon 2020 Programme through Grant Agreement No. 731019 (EUSMI). S.B., A.P., and V.P. gratefully acknowledge the financial support from the Italian Ministry of University and Research (MIUR) through grant “Dipartimenti di Eccellenza2017 Materials For Energy”.; sygma |
Approved |
Most recent IF: 13.858 |
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Call Number |
UA @ admin @ c:irua:176584 |
Serial |
6726 |
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Author |
Toso, S.; Akkerman, Q.A.; Martin-Garcia, B.; Prato, M.; Zito, J.; Infante, I.; Dang, Z.; Moliterni, A.; Giannini, C.; Bladt, E.; Lobato, I.; Ramade, J.; Bals, S.; Buha, J.; Spirito, D.; Mugnaioli, E.; Gemmi, M.; Manna, L. |
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Title ![sorted by Title field, ascending order (up)](img/sort_asc.gif) |
Nanocrystals of lead chalcohalides : a series of kinetically trapped metastable nanostructures |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of The American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
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Volume |
142 |
Issue |
22 |
Pages |
10198-10211 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We report the colloidal synthesis of a series of surfactant-stabilized lead chalcohalide nanocrystals. Our work is mainly focused on Pb4S3Br2, a chalcohalide phase unknown to date that does not belong to the ambient-pressure PbS-PbBr2 phase diagram. The Pb4S3Br2 nanocrystals herein feature a remarkably narrow size distribution (with a size dispersion as low as 5%), a good size tunability (from 7 to similar to 30 nm), an indirect bandgap, photoconductivity (responsivity = 4 +/- 1 mA/W), and stability for months in air. A crystal structure is proposed for this new material by combining the information from 3D electron diffraction and electron tomography of a single nanocrystal, X-ray powder diffraction, and density functional theory calculations. Such a structure is closely related to that of the recently discovered high-pressure chalcohalide Pb4S3I2 phase, and indeed we were able to extend our synthesis scheme to Pb4S3I2 colloidal nanocrystals, whose structure matches the one that has been published for the bulk. Finally, we could also prepare nanocrystals of Pb3S2Cl2, which proved to be a structural analogue of the recently reported bulk Pb3Se2Br2 phase. It is remarkable that one high-pressure structure (for Pb4S3I2) and two metastable structures that had not yet been reported (for Pb4S3Br2 and Pb3S2Cl2) can be prepared on the nanoscale by wet-chemical approaches. This highlights the important role of colloidal chemistry in the discovery of new materials and motivates further exploration into metal chalcohalide nanocrystals. |
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Wos |
000538526500035 |
Publication Date |
2020-05-06 |
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ISSN |
0002-7863 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
15 |
Times cited |
32 |
Open Access |
OpenAccess |
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Notes |
; We would like to thank Dr. A. Toma for the access to the IIT clean room facilities' SEM/FIB and evaporators, the Smart Materials group (IIT) for the access to the ATR-FTIR equipment, S. Marras for the support during XRPD measurements, G. Pugliese for help with the TGA measurements, M. Campolucci for help with the experiments on NC growth kinetics, S. Lauciello for help with the SEM-EDX analyses, and D. Baranov and R. Brescia for the helpful discussions. We also acknowledge funding from the Programme for Research and Innovation Horizon 2020 (2014-2020) under the Marie Sklodowska-Curie Grant Agreement COMPASS No. 691185. I.I. acknowledges the Dutch NWO for financial support under the Vidi scheme (Grant No. 723.013.002). S.B. acknowledges support by means of the ERC Consolidator Grant No. 815128 REALNANO. E. M. and M.G acknowledge the Regione Toscana for funding the purchase of the Timepix detector through the FELIX project (Por CREO FESR 2014-2020 action). ; sygma |
Approved |
Most recent IF: 15; 2020 IF: 13.858 |
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Call Number |
UA @ admin @ c:irua:170218 |
Serial |
6566 |
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