TY - JOUR
T1 - Organic-organic interfaces and unoccupied electronic states of thin films of perylene and naphthalene derivatives
AU - Kamounah, Fadhil S.
AU - Komolov, A.S
AU - Juul Møller, Preben
AU - Aliaev, Y. G.
AU - Lazneva, E. F.
AU - Akhremtchik, S.
AU - Mortensen, John
AU - Schaumburg, Kjeld
PY - 2005
Y1 - 2005
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 (EF) 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 π( band located 5–7.5 eV above EF for all the four films under study and the higher located σ*1 and σ*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 σ*1 and σ*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.
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 (EF) 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 π( band located 5–7.5 eV above EF for all the four films under study and the higher located σ*1 and σ*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 σ*1 and σ*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.
KW - Surface electronic phenomena
KW - Electron–solid interaction
KW - Electronic band structure
KW - Organic–organic semiconductor interfaces
KW - Perylene and naphthalene derivatives
KW - Surface electronic phenomena
KW - Electron–solid interaction
KW - Electronic band structure
KW - Organic–organic semiconductor interfaces
KW - Perylene and naphthalene derivatives
U2 - 10.1016/j.molstruc.2005.01.047
DO - 10.1016/j.molstruc.2005.01.047
M3 - Journal article
VL - 744-747
SP - 145
EP - 149
JO - Computational and Theoretical Chemistry
JF - Computational and Theoretical Chemistry
SN - 2210-271X
M1 - 19
ER -