Improving operating lifetime of organic light-emittina diodes with perylene and derivatives as aggregating light-emitting-layer additives

Digest of Technical Papers - SID International Symposium

Volumn 38, Issue 1, 2007, Pages 1188-1192

  Jarikov, Viktor V ^a   Vargas, J Ramon ^a   Kondakov, Denis Y ^a   Young, Ralph H ^a   Klubek, Kevin P ^a   Liao, Liang Sheng ^a   Brown, Christopher T ^b  

^a EASTMAN KODAK COMPANY   (United States)

^b Plextronics Inc   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ADDITIVES; DERIVATIVES; LUMINANCE; POLYCYCLIC AROMATIC HYDROCARBONS;

EMISSION ZONE; HALF LIFE; LIGHT EMITTING LAYER ADDITIVES;

ORGANIC LIGHT EMITTING DIODES (OLED);

EID: 34547927213     PISSN: 0097966X     EISSN: None     Source Type: Conference Proceeding    
DOI: 10.1889/1.2785522     Document Type: Conference Paper

References (12)

1. H. Aziz, Z. D. Popovic, N.-X. Hu, A.-M. Hor, and G. Xu, Science 283, 1900 (1999);
2. H. Aziz and Z. D. Popovic, Chem. Mater. 16, 4522 (2004).
3. T. K. Hatwar, C. T. Brown, L. Cosimbescu, M. L. Ricks, J. P. Spindler, W. Begley, and J. R. Vargas, SPIE 5519, 1 (2004).
4. C. T. Brown and D. Y. Kondakov, J. SID 12, 323 (2004);
5. T. K. Hatwar, G. Rajeswaran, C. W. Tang, and J. S. Shi, U.S. Patent No. 6,475,648, 2001.
6. V. V. Jarikov, J. Appl. Phys. 100, 014901 (2006);
7. V. V. Jarikov, R. H. Young, J. R. Vargas, C. T. Brown, K. P. Klubek, and L.-S. Liao, J. Appl. Phys. 100, 094907 (2006).
8. x | 750 Å NPB |350 ÅTBADN (or 450 ÅAlq) + x% additive | 300 Å Alq | 2100 ÅMg:Ag 20:1. ITO is the anode and Mg:Ag is the cathode.
9. One factor limiting the useful PAH concentration is the need for balanced charge injection and transport in the LEL. Also, at sufficiently high concentrations (e.g., >30% perylene or DBP in TBADN), PAH additives undergo crystallization during device construction. This undesired event nearly completely shuts down the EL. The crystallization threshold concentrations are higher in Alq.
10. R. H. Young, C. W. Tang, and A. P. Marchetti, Appl. Phys. Lett. 80, 874 (2002);
11. Y. Luo, H. Aziz, G. Xu, and Z. D. Popovic, Chem. Mater. 000 (2007).
12. Note that perylene was studied in a 0.3-25% range because OLEDs with >30% perylene in a TBADN LEL show no EL as a result of crystallization of perylene. However, TBP, which was originally designed as an aggregation- resistant blue dopant, was explored in a 0.3-100% range because its ability to crystallize is strongly impaired by the four bulky t-Bu groups. Even neat TBP films are amorphous, pin-holefree, and morphologically stable. Also note that vol % is used to indicate concentration of perylene and TBP in the LEL. However, vol % and molarity differ, e.g., 1.1 M corresponds to ∼23 vol % of perylene and ∼50 vol % of TBP.