TY - JOUR

T1 - Organic-organic interfaces and unoccupied electronic states of thin films of perylene and naphthalene derivatives

AU - Komolov, AS

AU - Moller, PJ

AU - Aliaev, YG

AU - Lazneva, EF

AU - Akhremtchik, S

AU - Kamounah, FS

AU - Mortensen, J

AU - Schaumburg, K

PY - 2005/6/3

Y1 - 2005/6/3

N2 - Thin films of N,N'-Bis(benzyl)-3,4,9,10-perylenetetracarboxylic diimide (BPTCDI, Fig. 1b) and N,N'-Bis(benzyl)-1,4,5,8-naphthalenetetracarboxylic diimide (BNTCDI, Fig. 1d) were thermally deposited in UHV on 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA, Fig. 1a) and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA, Fig. 1c) film surfaces, respectively, in order to form organic-organic interfaces so that molecules constituting the interfacing layers differ by the substituent group. The surface potential and the density of unoccupied electron states (DOUS) located 5-25 eV above the Fermi level (E-F) were measured during the film deposition using an incident beam of low-energy electrons according to the total current electron spectroscopy (TCS) method. Analysis of the TCS data allowed us to assign the pi( band located 5-7.5 eV above E-F for all the four films under study and the higher located sigma*(1) and sigma*(2) bands and the splitting within them. In order to perform the analysis the molecules were hypothetically divided into benzene-like, conjugated and non-conjugated fragments that may individually contribute to the peaks in the DOUS bands. It was shown that a non-conjugated fragment would serve for decreasing of the energy corresponding to the sigma*(1) and sigma*(2) bands and the sub-bands within them while an addition of a benzene-like fragment would do the opposite. The BPTCDI/PTCDA and BNTCDI/NTCDA interfaces were found non-reacted and a 4.1 +/- 0.1 eV work function value for both BPTCDI and BNTCDI films was determined, which is about 0.25 eV lower than the work functions of the PTCDA and the NTCDA films. (c) 2005 Elsevier B.V. All rights reserved.

AB - Thin films of N,N'-Bis(benzyl)-3,4,9,10-perylenetetracarboxylic diimide (BPTCDI, Fig. 1b) and N,N'-Bis(benzyl)-1,4,5,8-naphthalenetetracarboxylic diimide (BNTCDI, Fig. 1d) were thermally deposited in UHV on 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA, Fig. 1a) and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA, Fig. 1c) film surfaces, respectively, in order to form organic-organic interfaces so that molecules constituting the interfacing layers differ by the substituent group. The surface potential and the density of unoccupied electron states (DOUS) located 5-25 eV above the Fermi level (E-F) were measured during the film deposition using an incident beam of low-energy electrons according to the total current electron spectroscopy (TCS) method. Analysis of the TCS data allowed us to assign the pi( band located 5-7.5 eV above E-F for all the four films under study and the higher located sigma*(1) and sigma*(2) bands and the splitting within them. In order to perform the analysis the molecules were hypothetically divided into benzene-like, conjugated and non-conjugated fragments that may individually contribute to the peaks in the DOUS bands. It was shown that a non-conjugated fragment would serve for decreasing of the energy corresponding to the sigma*(1) and sigma*(2) bands and the sub-bands within them while an addition of a benzene-like fragment would do the opposite. The BPTCDI/PTCDA and BNTCDI/NTCDA interfaces were found non-reacted and a 4.1 +/- 0.1 eV work function value for both BPTCDI and BNTCDI films was determined, which is about 0.25 eV lower than the work functions of the PTCDA and the NTCDA films. (c) 2005 Elsevier B.V. All rights reserved.

KW - surface electronic phenomena

KW - electron-solid interaction

KW - electronic band structure

KW - organic-organic semiconductor interfaces

KW - perylene and naphthalene derivatives

KW - TARGET-CURRENT-SPECTROSCOPY

KW - CU-PHTHALOCYANINE FILMS

KW - BAND-STRUCTURE

KW - SEMICONDUCTOR

KW - SURFACES

KW - PHOTOEMISSION

KW - HYDROCARBONS

KW - DIFFRACTION

KW - MOLECULES

KW - GRAPHITE

U2 - 10.1016/j.molstruc.2005.01.047

DO - 10.1016/j.molstruc.2005.01.047

M3 - статья

VL - 744

SP - 145

EP - 149

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

SN - 0022-2860

Y2 - 5 September 2004 through 10 September 2004

ER -