Concentration quenching effect of organic light‐emitting devices using DCM1‐doped tetraphenylgermole |
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Authors: | Young H Park Yongmin Kim Honglae Sohn Ki‐Seok An |
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Institution: | 1. Department of Applied Physics and the Institute of Nanosensors and Biotechnology, Dankook University, , Gyeonggi‐Do, 448‐701 Korea;2. Department of Chemistry, Chosun University, , Kwangju, 501‐759 Korea;3. Device Materials Research Center, Korea Research Institute of Chemical Technology, , Daejeon, 305‐343 Korea |
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Abstract: | We examine the concentration quenching of a 4‐(dicyanomethylene)2‐methyl‐6‐(p‐dimethylaminostyryl)‐4H‐pyran (DCM1)‐doped 1,1‐bis(2‐phenylethynyl)‐2,3,4,5‐tetraphenylgermole (HPAG)‐based light‐emitting diode. Originally, HPAG emits in the ~500‐nm (green) region, which can be converted to a red‐emission material by using DCM1 doping. As the DCM1 concentration increased from 1 to 10 wt%, the electroluminescence peak positions are red‐shifted from 604 to 644 nm, respectively. Increasing doping density not only shows the red‐shift but also shows decreasing luminance efficiency. Förster energy transfer between the HPAG host material and the DCM1 guest material is responsible for the strong red‐emission behavior. The calculated Förster radius (4.0 nm) for excellent Förster energy transfer characteristics with increasing doping concentration of DCM1 is consistent with experimental results. The maximum luminance efficiency was 6.64 cd/A at 11.0 mA/cm2. The HPAG germole compound shows excellent red‐emission host–guest system properties for red organic light‐emitting device applications. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | germole luminance efficiency OLED photoluminescence |
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