Blue nonblinking (>98% “on” time) ZnCdSe/ZnS//ZnS quantum dots (QDs) with absolute fluorescence quantum yield (QY) of 92% (λ_peak = 472 nm) were synthesized via a low temperature nucleation and high temperature shell growth method. Such bright nonblinking ZnCdSe/ZnS//ZnS core/shell QDs exhibit not only good emission tunability in the blue-cyan range with corresponding wavelength from 450 to 495 nm but also high absolute photoluminescence (PL) QY and superior chemical and photochemical stability. Highly efficient blue quantum dot-based light-emitting diodes (QLEDs) have been demonstrated by using nonblinking ZnCdSe/ZnS//ZnS QDs as emissive layer, and the charge–injection balance within the QD active layer was improved by introducing a nonconductive layer of poly(methyl methacrylate) (PMMA) between the electron transport layer (ETL) and the QD layer, where the PMMA layer takes the role of coordinator to impede excessive electron flux. The best device exhibits outstanding features such as maximum luminance of 14,100 cd/m², current efficiency of 11.8 cd/A, and external quantum efficiency (EQE) of 16.2%. Importantly, the peak efficiency of the QLEDs with PMMA is achieved at ∼1,000 cd/m² and high EQE > 12% can be sustained in the range of 100 to 3,000 cd/m².

中文翻译：

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高效，平衡电荷注入过程的基于非闪烁量子点的蓝色发光二极管

蓝色非闪烁（> 98％“开启”时间）ZnCdSe / ZnS // ZnS量子点（QD），绝对荧光量子产率（QY）为92％（λ_峰值）通过低温成核和高温壳生长法合成了约472nm（约472nm）的碳纳米管。这种明亮的非闪烁ZnCdSe / ZnS // ZnS核/壳QD不仅在蓝绿色范围内具有从450到495 nm的相应波长的良好发射可调性，而且还具有很高的绝对光致发光（PL）QY和优异的化学和光化学稳定性。通过使用非闪烁的ZnCdSe / ZnS // ZnS量子点作为发光层，已经证明了高效的基于蓝色量子点的发光二极管（QLED），并且通过引入非导电层提高了QD有源层内的电荷注入平衡。电子传输层（ETL）和QD层之间的聚（甲基丙烯酸甲酯）（PMMA），其中PMMA层起着配位剂的作用，以阻止过多的电子通量。^{如图2所示}，电流效率为11.8 cd / A，外部量子效率（EQE）为16.2％。重要的是，具有PMMA的QLED的峰值效率达到约1,000 cd / m ^2，并且EQE> 12％的高EQE可以维持在100到3,000 cd / m ²的范围内。