title: Adsorption and thermal decomposition of 2-octylthieno[3,4-b]thiophene on Au(111).
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 (9×2√33)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.
authors: Institute of Fusion Science, Department of Chemistry Education, Chonbuk National University, Jeonbuk 560-756, Republic of Korea. joonbumpark@jbnu.ac.kr
authors: Joon B
authors: JB
authors: Park
authors: Kyukwan
authors: K
authors: Zong
authors: Il Chul
authors: IC
authors: Jeon
authors: Jae Ryang
authors: JR
authors: Hahn
authors: Dario
authors: D
authors: Stacchiola
authors: David
authors: D
authors: Starr
authors: Kathrin
authors: K
authors: Müller
authors: Jaegeun
authors: J
authors: Noh