Records |
Author |
Jain, N.; Hao, Y.; Parekh, U.; Kaltenegger, M.; Pedrazo-Tardajos, A.; Lazzaroni, R.; Resel, R.; Geerts, Y.H.; Bals, S.; Van Aert, S. |
Title ![sorted by Title field, ascending order (up)](img/sort_asc.gif) |
Exploring the effects of graphene and temperature in reducing electron beam damage: A TEM and electron diffraction-based quantitative study on Lead Phthalocyanine (PbPc) crystals |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Micron |
Abbreviated Journal |
|
Volume |
169 |
Issue |
|
Pages |
103444 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
High-resolution transmission electron microscopy (TEM) of organic crystals, such as Lead Phthalocyanine (PbPc), is very challenging since these materials are prone to electron beam damage leading to the breakdown of the crystal structure during investigation. Quantification of the damage is imperative to enable high-resolution imaging of PbPc crystals with minimum structural changes. In this work, we performed a detailed electron diffraction study to quantitatively measure degradation of PbPc crystals upon electron beam irradiation. Our study is based on the quantification of the fading intensity of the spots in the electron diffraction patterns. At various incident dose rates (e/Å2/s) and acceleration voltages, we experimentally extracted the decay rate (1/s), which directly correlates with the rate of beam damage. In this manner, a value for the critical dose (e/Å2) could be determined, which can be used as a measure to quantify beam damage. Using the same methodology, we explored the influence of cryogenic temperatures, graphene TEM substrates, and graphene encapsulation in prolonging the lifetime of the PbPc crystal structure during TEM investigation. The knowledge obtained by diffraction experiments is then translated to real space high-resolution TEM imaging of PbPc. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000965998800001 |
Publication Date |
2023-03-21 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0968-4328 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.4 |
Times cited |
1 |
Open Access |
OpenAccess |
Notes |
This work is supported by FWO and FNRS within the 2Dto3D network of the EOS (Excellence of Science) program (grant number 30489208) and ERC-CoGREALNANO-815128 (to Prof. Dr. Sara Bals). N.J. would like to thank Dr. Kunal S. Mali and Dr. Da Wang for useful and interesting discussions on sample preparation procedures. |
Approved |
Most recent IF: 2.4; 2023 IF: 1.98 |
Call Number |
EMAT @ emat @c:irua:196069 |
Serial |
7379 |
Permanent link to this record |
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Author |
Hao, Y.; Velpula, G.; Kaltenegger, M.; Bodlos, W.R.; Vibert, F.; Mali, K.S.; De Feyter, S.; Resel, R.; Geerts, Y.H.; Van Aert, S.; Beljonne, D.; Lazzaroni, R. |
Title ![sorted by Title field, ascending order (up)](img/sort_asc.gif) |
From 2D to 3D : bridging self-assembled monolayers to a substrate-induced polymorph in a molecular semiconductor |
Type |
A1 Journal article |
Year |
2022 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
34 |
Issue |
5 |
Pages |
2238-2248 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
In this study, a new bottom-up approach is proposed to predict the crystal structure of the substrate-induced polymorph (SIP) of an archetypal molecular semiconductor. In spite of intense efforts, the formation mechanism of SIPs is still not fully understood, and predicting their crystal structure is a very delicate task. Here, we selected lead phthalocyanine (PbPc) as a prototypical molecular material because it is a highly symmetrical yet nonplanar molecule and we demonstrate that the growth and crystal structure of the PbPc SIPs can be templated by the corresponding physisorbed self-assembled molecular networks (SAMNs). Starting from SAMNs of PbPc formed at the solution/graphite interface, the structural and energetic aspects of the assembly were studied by a combination of in situ scanning tunneling microscopy and multiscale computational chemistry approach. Then, the growth of a PbPc SIP on top of the physisorbed monolayer was modeled without prior experimental knowledge, from which the crystal structure of the SIP was predicted. The theoretical prediction of the SIP was verified by determining the crystal structure of PbPc thin films using X-ray diffraction techniques, revealing the formation of a new polymorph of PbPc on the graphite substrate. This study clearly illustrates the correlation between the SAMNs and SIPs, which are traditionally considered as two separate but conceptually connected research areas. This approach is applicable to molecular materials in general to predict the crystal structure of their SIPs. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000812125800001 |
Publication Date |
2022-02-17 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756; 1520-5002 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.6 |
Times cited |
|
Open Access |
Not_Open_Access |
Notes |
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Approved |
Most recent IF: 8.6 |
Call Number |
UA @ admin @ c:irua:189086 |
Serial |
7084 |
Permanent link to this record |