Cadmium-free quantum dots based violet light-emitting diodes: High-efficiency and brightness via optimization of organic hole transport layers

2015 ◽  
Vol 25 ◽  
pp. 178-183 ◽  
Author(s):  
Qingli Lin ◽  
Huaibin Shen ◽  
Hongzhe Wang ◽  
Aqiang Wang ◽  
Jinzhong Niu ◽  
...  
Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 344 ◽  
Author(s):  
Neng Liu ◽  
Sijiong Mei ◽  
Dongwei Sun ◽  
Wuxing Shi ◽  
Jiahuan Feng ◽  
...  

High efficiency blue fluorescent organic light-emitting diodes (OLEDs), based on 1,3-bis(carbazol-9-yl)benzene (mCP) doped with 4,4’-bis(9-ethyl-3-carbazovinylene)-1,1’-biphenyl (BCzVBi), were fabricated using four different hole transport layers (HTLs) and two different electron transport layers (ETLs). Fixing the electron transport material TPBi, four hole transport materials, including 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N’-Di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4’-diamine(NPB), 4,4’-Bis(N-carbazolyl)-1,1,-biphenyl (CBP) and molybdenum trioxide (MoO3), were selected to be HTLs, and the blue OLED with TAPC HTL exhibited a maximum luminance of 2955 cd/m2 and current efficiency (CE) of 5.75 cd/A at 50 mA/cm2, which are 68% and 62% higher, respectively, than those of the minimum values found in the device with MoO3 HTL. Fixing the hole transport material TAPC, the replacement of TPBi ETL with Bphen ETL can further improve the performance of the device, in which the maximum luminance can reach 3640 cd/m2 at 50 mA/cm2, which is 23% higher than that of the TPBi device. Furthermore, the lifetime of the device is also optimized by the change of ETL. These results indicate that the carrier mobility of transport materials and energy level alignment of different functional layers play important roles in the performance of the blue OLEDs. The findings suggest that selecting well-matched electron and hole transport materials is essential and beneficial for the device engineering of high-efficiency blue OLEDs.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wei-Chih Chao ◽  
Tzu-Hsuan Chiang ◽  
Yi-Chun Liu ◽  
Zhi-Xuan Huang ◽  
Chia-Chun Liao ◽  
...  

AbstractThe industrialization of quantum dot light-emitting diodes (QLEDs) requires the use of less hazardous cadmium-free quantum dots, among which ZnSe-based blue and InP-based green and red quantum dots have received considerable attention. In comparison, the development of InP-based green QLEDs is lagging behind. Here, we prepare green InP/ZnSe/ZnS quantum dots with a diameter of 8.6 nm. We then modify the InP quantum dot emitting layer by passivation with various alkyl diamines and zinc halides, which decreases electron mobility and enhances hole transport. This, together with optimizing the electron transport layer, leads to green 545 nm InP QLEDs with a maximum quantum efficiency (EQE) of 16.3% and a current efficiency 57.5 cd/A. EQE approaches the theoretical limit of InP quantum dots, with an emission quantum yield of 86%.


2020 ◽  
Vol 28 (5) ◽  
pp. 6134 ◽  
Author(s):  
Fei Chen ◽  
Li-Jin Wang ◽  
Xu Li ◽  
Zhen-Bo Deng ◽  
Feng Teng ◽  
...  

2020 ◽  
Vol 28 (5) ◽  
pp. 401-409 ◽  
Author(s):  
Tatsuya Ryowa ◽  
Takeshi Ishida ◽  
Yusuke Sakakibara ◽  
Keisuke Kitano ◽  
Masaya Ueda ◽  
...  

2019 ◽  
Vol 6 (10) ◽  
pp. 2009-2015 ◽  
Author(s):  
Zhiwen Yang ◽  
Qianqian Wu ◽  
Gongli Lin ◽  
Xiaochuan Zhou ◽  
Weijie Wu ◽  
...  

An all-solution processed inverted green quantum dot-based light-emitting diode with concurrent high efficiency and long lifetime is obtained by precisely controlled double shell growth of quantum dots.


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