Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to the...Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to theircommercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fastdegradation of OLEDs. In particular, we focus on the origin of the dark spots by 'rebuilding' cathodes, which confirms thatthe growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from thesearch for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation andmoisture resistance, in addition to electrical insulation.展开更多
A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electr...A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices （OLEDs）, a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide （ITO） anode etched by a conventional strong etchant of aqua regia.展开更多
A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found t...A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.展开更多
The Ce （x nm）/Au （15 nm） stacked layers were used as semitransparent cathodes in the top-emission organic light emitting devices （TOLEDs） fabricated on a p-type silicon anodes and substrate,where x varies from 4...The Ce （x nm）/Au （15 nm） stacked layers were used as semitransparent cathodes in the top-emission organic light emitting devices （TOLEDs） fabricated on a p-type silicon anodes and substrate,where x varies from 4 to 16.The consequence of the Ce layer thickness on transmittance and the device performance were studied when the organic layers NPB （60 nm）/ALQ （60 nm） were kept unchanged,where NPB was N,N＇-bis-（1-naphthl）-diphenyl-1,1＇-biphenyl-4,4＇-diamine,and AlQ is tris-（8-hydroxyquinoline） aluminum.The cathode of Ce （11 nm）/Au （15 nm） has a transparency of 46%,and the TOLED with it achieves the highest luminescence efficiencies：a current efficiency of 0.91 cd/A at 13.7 V and a peak power efficiency of 0.28 lm/W at 9 V.The turn-on voltage is 3.0 V.The Ce/Au cathode is both chemically and electrically stable.展开更多
文摘Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to theircommercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fastdegradation of OLEDs. In particular, we focus on the origin of the dark spots by 'rebuilding' cathodes, which confirms thatthe growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from thesearch for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation andmoisture resistance, in addition to electrical insulation.
基金supported by the National Natural Science Foundation of China(Grant Nos.61307036 and 61307037)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Chinathe University Science Research Project of Jiangsu Province,China(Grant No.12KJB510028)
文摘A controllable etching process for indium zinc oxide （IZO） films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices （OLEDs）, a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide （ITO） anode etched by a conventional strong etchant of aqua regia.
文摘A systematic study has been conducted on microcavity organic light emitting diodes(OLEDs)based on green,red and blue phosphorescent emitters to elucidate the microcavity effects for different color emitters.We found that the luminance output is determined by the reflectivity of the semitransparent electrode and the photopic response of the green,red and blue emitters.While the luminance enhancements of blue and red phosphorescent microcavity devices are small,a current efficiency as high as 224 cd A21 is obtained in the green phosphorescent microcavity OLEDs.
文摘The Ce （x nm）/Au （15 nm） stacked layers were used as semitransparent cathodes in the top-emission organic light emitting devices （TOLEDs） fabricated on a p-type silicon anodes and substrate,where x varies from 4 to 16.The consequence of the Ce layer thickness on transmittance and the device performance were studied when the organic layers NPB （60 nm）/ALQ （60 nm） were kept unchanged,where NPB was N,N＇-bis-（1-naphthl）-diphenyl-1,1＇-biphenyl-4,4＇-diamine,and AlQ is tris-（8-hydroxyquinoline） aluminum.The cathode of Ce （11 nm）/Au （15 nm） has a transparency of 46%,and the TOLED with it achieves the highest luminescence efficiencies：a current efficiency of 0.91 cd/A at 13.7 V and a peak power efficiency of 0.28 lm/W at 9 V.The turn-on voltage is 3.0 V.The Ce/Au cathode is both chemically and electrically stable.
