Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 143
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3098
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Severity: Warning
Message: Attempt to read property "Count" on bool
Filename: helpers/my_audit_helper.php
Line Number: 3100
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3100
Function: _error_handler
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
We show how gadolinium (Gd)-based metallofullerene (GdN@C) molecules can be used to create single adatoms and nanoclusters on a graphene surface. An in situ heating holder within an aberration-corrected scanning transmission electron microscope is used to track the adhesion of endohedral metallofullerenes (MFs) to the surface of graphene, followed by Gd metal ejection and diffusion across the surface. Heating to 900 °C is used to promote adatom migration and metal nanocluster formation, enabling direct imaging of the assembly of nanoclusters of Gd. We show that hydrogen can be used to reduce the temperature of MF fragmentation and metal ejection, enabling Gd nanocluster formation on graphene surfaces at temperatures as low as 300 °C. The process of MF fragmentation and metal ejection is captured in situ and reveals that after metal release, the C cage opens further and fuses with the surface monolayer carbon glass on graphene, creating a highly stable carbon layer for further Gd adatom adhesion. Small voids and defects (∼1 nm) in the surface carbon glass act as trapping sites for Gd atoms, leading to atomic self-assembly of 2D monolayer Gd clusters. These results show that MFs can adhere to graphene surfaces at temperatures well above their bulk sublimation point, indicating that the surface bound MFs have strong adhesion to dangling bonds on graphene surfaces. The ability to create dispersed single Gd adatoms and Gd nanoclusters on graphene may have impact in spintronics and magnetism.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1021/acsnano.8b06057 | DOI Listing |
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