Angle-resolved UV photoelectron spectra (UPS) of thin films of perylene-3,4,9,10-tetracarboxylic dianhydride on MoS₂

Abstract

Angle-resolved UV photoelectron spectra (ARUPS) were measured for thin ®lms of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) deposited on cleaved MoS 2 surfaces. The take-off angle ( ) dependence of the photoelectron intensity of the highest % band showed a sharp maximum at = 32±34 . A spectral feature of the binding energy at $8.9 eV, which is believed to originate from a % state, showed a remarkably different dependence from that of the % band. A quantitative analysis of the observed dependencies clearly indicates that (a) the feature at $8.9 eV originates from the oxygen 2p nonbonding states and (b) the molecules lie¯at on the substrate surface.

Angle-resolved ultraviolet photoelectron spectroscopy of In-[perylene-3,4,9,10-tetracarboxylic dianhydride] system

“…In general, when large -conjugated planner molecules, such as PTCDA and phthalocyanines lie flat on the substrate surface, the dependence of the photoelectron intensity from the single band, which spreads over the molecule, showed a value of max ϭ32°-36°with very sharp angular distribution due to the initial-state interference effects. 5,7,10 The broader angular distribution for the X band suggests that the molecular plane becomes tilted by the reaction after In deposition.…”

“…We have already reported that the dependence of the top -band intensity of PTCDA thin films grown on MoS 2 surfaces showed little film-thickness dependence for the film thickness of 1.4-42 Å and the molecules lie with molecular plane being parallel ͑molecular tilt angle of ␤ϭ0°͒ to the substrate surface. 7 The angular dependence of the band X intensity shows a maximum at max ϭ36°-40°with a broader angular distribution than the top band of the pristine PTCDA. In general, when large -conjugated planner molecules, such as PTCDA and phthalocyanines lie flat on the substrate surface, the dependence of the photoelectron intensity from the single band, which spreads over the molecule, showed a value of max ϭ32°-36°with very sharp angular distribution due to the initial-state interference effects.…”

“…7 The assignment for each band in the spectra was already made with the ab initio calculation ͑STO-6G͒ and the quantitative analysis of the photoelectron intensity. 7 Briefly, bands A(E B ϭ2.2 eV), B(4.0 eV), and D(5.7 eV) which show the intensity maximum at Х34°, 34°and 46°, respectively, originate mainly from states.…”

“…7 The assignment for each band in the spectra was already made with the ab initio calculation ͑STO-6G͒ and the quantitative analysis of the photoelectron intensity. 7 Briefly, bands A(E B ϭ2.2 eV), B(4.0 eV), and D(5.7 eV) which show the intensity maximum at Х34°, 34°and 46°, respectively, originate mainly from states. Among these, the band A which consists of single molecular orbital ͑MO͒, and the feature C(E B ϭ4.6 eV) which appears only at a larger value of originates from oxygen 2p nonbonding state (n Oʈ ) at CvO parts with O 2px and 2py atomic orbitals ͑AOs͒.…”

Chemical bonding of PTCDA on Ag surfaces and the formation of interface states

“…We note that several publications address the adsorption of PTCDA on Ag [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] or other surfaces [2,[19][20][21][22][23][24][25], and also similar molecules have been investigated as adsorbates [1,2,7,20,[26][27][28][29][30][31][32][33]. Here, we concentrate on the chemical bonding and on electronic interface states using several complementary high-resolution techniques.…”