Light Emitting Diodes Based on Polyaniline

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Printed in the Republic of Korea

* ^†^‡

†

‡, NKIC (2000. 8. 23 )

Light Emitting Diodes Based on Polyaniline

Eun Ok Kim*, Soo Beom Park, Seok Heo^†, and Sung Joo Lee^‡ Department of Chemistry, The University of Suwon, Kyunggi 445-742, Korea

†Samhwa Electric Co. LTD., Chongju, Chungbuk 361-270 Korea

‡Lab. Solution NKIC, Seodaemun-gu, Seoul 120-100, Korea (Received August 23, 2000)

. !"# $%& '() FT-IR, UV-Vis, GPC, TG-DTA& * ( +,)-.. ITO /01 .23 LEB-PANI/NMP 45%& 6789):, Al ;# <=

>?) @AB CD.EFGH IJ): I-V *( EL 6KLM# NO)-.. UV-Vis 6KLM1P Q RSO LEB TUE >VW π→π*E XYXEZ + [\] E ^ _`): PL

EL ^ >)a b# NO)-.. ITO/LEB/Al cd LED1P JZ ef 5 VEg.. hiDf @

!" RS cd1Pj CD)a b# NO)-..

ABSTRACT. Various oxidation states of Polyaniline(PANI) were chemically synthesized, and characterized by FT-IR, UV-Vis, GPC, TG-DTA. Single layer light emitting diodes(LED) were prepared by spin coating of LEB-PANI solutions which have various oxidation states onto an ITO substrate and subsequent vacuum deposition of aluminum top electrode and then current-voltage characteristics, EL spectrum was investigated.

It was found that π→π∗ transition were shifted to longer wavelength and molecular exciton transition were decreased in the UV-Vis spectra and the intensity of EL and PL were increased as the contents of fully reduced form LEB increased. The turn-on voltage of ITO/LEB/Al structured LED was 5 V. It was found that the white light was emitted only from the phase with reduced repeat unit.

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# Ôg..

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£ VH Source Measurement Unit(KEITHLEY 236)

& à)-..

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!" É'qf .Þ ¥..

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´k Õ Å ýýñ _`) 40+ EÅ1a o ¯ ya þ# p¤: .. E qf 40+1 Õ b# V %p q# ¼

\Í 0t 90+ Z¼ q# <\.. UV-Vis, FT-IR+D& '(Õ !"# NO)-..

Fig. 11 UV-Vis spectrum# p¤g.. E 

&r EB£ LEB# V g..^7-9 LEB

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s3 (LEB£ EB TU)H ¯ \Ð à3 UV-Vis 6KLM# Fig. 21 p¤g: πüπ* E

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j 1497 cm⁻¹ S : C=C <Z Äj Fig. 1. UV-Vis spectra of emeraldine base. (−−−) and leu-

coemeraldine base(---).

Fig. 2. UV-Vis spectra of PANI for the contents of LEB in NMP solution.

Fig. 3. Correlation diagram for the contents of LEB and λmax

of molecular exciton(A) ratio π→π*(B).

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Äa pp À.. 1304 cm⁻¹Äa -C-NH-j

w)& Éx À.. E '(Õ \áa LEB& V g..

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Fig. 5. FT-IR spectrum of leucoemeraldine base.

Fig. 6. PL spectra of PANI for the contents of LEB in NMP solution.

Fig. 7. Correlation diagram for PL intensity vs. the contents of LEB.

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>?Õ z{ E ùfi%& Õ..

Al;1 Þ;# ITO ;1 2;# ):

Fig. 8. I-V characteristics of the ITO/LEB/Al structured LED.

Fig. 9. EL spectrum of the ITO/PANI/Al structured LED at the applied voltage 5.4 V.

Fig. 10. Correlation diagram for EL intensity vs. the contents of LEB.

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) Fig. 91 p¤g:. LEB TU1 Â EL

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~ hiD# p¤g: λmax EZf LEB TU

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_`) πüπ* E XYX%& EZ):, +[\]

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Light Emitting Diodes Based on Polyaniline  

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Light Emitting Diodes Based on Polyaniline

Light Emitting Diodes Based on Polyaniline