摘要
近十年来,制备近紫外有机发光二极管成为有机电子学领域的研究热点之一.但是当器件的电致发光波长延伸到400 nm以下后,对器件中各功能层的材料选择提出了更高要求.本实验中,以宽带隙小分子材料BCPO(bis-4-(N-carbazolyl)phenyl)phenylphosphine oxide)为发光层,基于BCPO的发射光谱确定了电子传输材料和空穴传输材料,制备了电致发光峰位波长在384 nm附近的近紫外有机发光二极管.在最佳的器件结构下,器件的最大外量子效率达到2.98%,最大辐射功率达到38.2 mW/cm^(2).电致发光谱中波长在400 nm以下的近紫外光占比为57%.结果表明器件在恒压模式下展示了良好的稳定性,此外,对影响器件稳定性的多个关键因素给予了深入的分析.
To date,in the traditional method of obtaining near-ultraviolet(NUV)light,mercury atoms,which can create a highly toxic heavy metal contaminant,have been used.Therefore,it is an important issue to obtain NUV light by using new environmentally friendly devices.In the last decade,the fabrication of near ultraviolet organic light-emitting diodes(NUV-OLEDs)has become a research hotspot in the field of organic electronics.However,when the electroluminescence wavelength is extended to shorter than 400 nm,higher requirements are put forward for the materials used for each functional layer in these devices.In this work,a wide bandgap small molecule material of BCPO is used as the luminescent layer.The electron-transporting and hole-transporting materials are determined based on the overlaps between absorption spectra of these materials and emission spectrum of BCPO.And NUV-OLEDs with electroluminescent peak wavelength at 384 nm are prepared.By using the optimal device structure,the maximum external quantum efficiency of the device reaches 2.98%,and the maximum radiance of the device reaches 38.2 mW/cm^(2).In the electroluminescence spectrum,NUV light with wavelengths below 400 nm accounts for 57%of the light emission.In addition,the device demonstrates good stability when biased at two different constant voltage modes.The multiple key factors which affect the stability of the device are analyzed in detail.Firstly,it is found that the high glass transition temperature(Tg)of hole-transporting material is very important for the long-time stability of this device.The poor device stability is closely related to the low Tg temperature of hole-transporting material.Secondly,due to the widespread use of PEDOT:PSS as hole injection material in OLEDs,the electron leakage from the hole-transpor layer into the PEDOT:PSS layer may cause significant damage to the conducting polymer.When bombarded with low energy electrons,bond breakage occurs on the surface of PEDOT:PSS,followed by the release of oxygen and sulfur,resulting in changes
作者
任兴
于宏宇
张勇
Ren Xing;Yu Hong-Yu;Zhang Yong(Chongqing Key Laboratory of Micro&Nano Structure Optoelectronics,School of Physical Science and Technology,Southwest University,Chongqing 400715,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第4期263-271,共9页
Acta Physica Sinica
关键词
有机发光二极管
近紫外光
辐射功率
外量子效率
organic light-emitting diode
near ultraviolet light
radiances
external quantum efficiency
