Adsorption and thermal decomposition of 2-octylthieno[3,4-b]thiophene on Au(111).
J Colloid Interface Sci
; 384(1): 143-8, 2012 Oct 15.
Article
in En
| MEDLINE
| ID: mdl-22818203
ABSTRACT
The adsorption and thermal stability of 2-octylthieno[3,4-b]thiophene (OTTP) on the Au(111) surfaces have been studied using scanning tunneling microscopy (STM), temperature programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). UHV-STM studies revealed that the vapor-deposited OTTP on Au(111) generated disordered adlayers with monolayer thickness even at saturation coverage. XPS and TPD studies indicated that OTTP molecules on Au(111) are stable up to 450 K and further heating of the sample resulted in thermal decomposition to produce H(2) and H(2)S via C-S bond scission in the thieno-thiophene rings. Dehydrogenation continues to occur above 600 K and the molecules were ultimately transformed to carbon clusters at 900 K. Highly resolved air-STM images showed that OTTP adlayers on Au(111) prepared from solution are composed of a well-ordered and low-coverage phase where the molecules lie flat on the surface, which can be assigned as a (9×2â33)R5° structure. Finally, based on analysis of STM, TPD, and XPS results, we propose a thermal decomposition mechanism of OTTP on Au(111) as a function of annealing temperature.
Full text:
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Colloid Interface Sci
Year:
2012
Document type:
Article