Contact potential difference measurements of doped organic molecular thin films

被引：8

作者：

Chan, C ^{[1
]}

Gao, WY ^{[1
]}

Kahn, A ^{[1
]}

机构：

[1] Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA

来源：

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A | 2004年 / 22卷 / 04期

关键词：

D O I：

10.1116/1.1688363

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

The possibility of nonequilibrium conditions in doped organic molecular thin films is investigated using a combination of ultraviolet photoemission spectroscopy (UPS) and contact potential difference measurements. Surface or interface photovoltage is of particular concern in materials with large band gap and appreciable band (or energy level) bending at interfaces. We investigate here zinc phthalocyanine (ZnPc) and N,N'-diphenyl-N,N-bis(1-naphthyl)-1,1'biphenyl-4,4" diamine (alpha-NPD) p-doped, with the acceptor molecule, tetrafluorotetracyanoquinodimethane (F-4-TCNQ). In both cases, we observe an upward movement of the vacuum level away from the metal interface with respect to the Fermi level, consistent with the formation of a depletion region. We show that photovoltage is not a significant factor in these doped films, under ultraviolet illumination during UPS. We suggest that the carrier recombination rate in organic films is sufficiently fast to exclude any photovoltage effects at room temperature. (C) 2004 American Vacuum Society.

引用

页码：1488 / 1492

页数：5

共 27 条

[11]

2-9

[12] Controlled p doping of the hole-transport molecular material N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine with tetrafluorotetracyanoquinodimethane [J].

Gao, WY ;

Kahn, A .

JOURNAL OF APPLIED PHYSICS, 2003, 94 (01) :359-366

[13] Electronic structure and current injection in zinc phthalocyanine doped with tetrafluorotetracyanoquinodimethane: Interface versus bulk effects [J].

Gao, WY ;

Kahn, A .

ORGANIC ELECTRONICS, 2002, 3 (02) :53-63

[14] Effect of electrical doping on molecular level alignment at organic-organic heterojunctions [J].

Gao, WY ;

Kahn, A .

APPLIED PHYSICS LETTERS, 2003, 82 (26) :4815-4817

[15] Controlled p-doping of zinc phthalocyanine by coevaporation with tetrafluorotetracyanoquinodimethane:: A direct and inverse photoemission study [J].

Gao, WY ;

Kahn, A .

APPLIED PHYSICS LETTERS, 2001, 79 (24) :4040-4042

[16] ROLE OF PHOTOCURRENT IN LOW-TEMPERATURE PHOTOEMISSION-STUDIES OF SCHOTTKY-BARRIER FORMATION [J].

HECHT, MH .

PHYSICAL REVIEW B, 1990, 41 (11) :7918-7921

[17]

Ishii H, 1999, ADV MATER, V11, P605, DOI 10.1002/(SICI)1521-4095(199906)11:8<605::AID-ADMA605>3.0.CO

[18]

2-Q

[19] Electronic structure and electrical properties of interfaces between metals and π-conjugated molecular films [J].

Kahn, A ;

Koch, N ;

Gao, WY .

JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 2003, 41 (21) :2529-2548

[20] Lack of thermodynamic equilibrium in conjugated organic molecular thin films [J].

Koch, N ;

Chan, C ;

Kahn, A ;

Schwartz, J .

PHYSICAL REVIEW B, 2003, 67 (19)

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