Tandem organic light-emitting diode with a molybdenum tri-oxide thin film interconnector layer

A 10-nm-thick molybdenum tri-oxide（MoO3） thin film was used as the interconnector layer in tandem organic lightemitting devices（OLEDs）.The tandem OLEDs with two identical emissive units consisting of N,N-bis（naphthalen-1-yl）N,N-bis（phenyl）-benzidine（NPB） /tris（8-hydroxyquinoline） aluminum（Alq3） exhibited current efficiency-current density characteristics superior to the conventional single-unit devices.At 20 mA/cm2,the current efficiency of the tandem OLEDs using the interconnector layers of MoO3 thin film was about 4.0 cd/A,which is about twice that of the corresponding conventional single-unit device（1.8cd/A）.The tandem OLED showed a higher power efficiency than the conventional single-unit device for luminance over 1200cd/m2.The experimental results demonstrated that a MoO3 thin film with a proper thickness can be used as an effective interconnector layer in tandem OLEDs.Such an interconnector layer can be easily fabricated by simple thermal evaporation,greatly simplifying the device processing and fabrication processes required by previously reported interconnector layers.A possible explanation was proposed for the carrier generation of the MoO3 interconnector layer.

Numerical model of tandem organic light-emitting diodes based on a transition metal oxide interconnector layer

By utilizing a two-step process to express the charge generation and separation mechanism of the transition metal oxides （TMOs） interconnector layer, a numerical model was proposed for tandem organic light emitting diodes （OLEDs） with a TMOs thin film as the interconnector layer. This model is valid not only for an n-type TMOs interconnector layer, but also for a p-type TMOs interconnector layer. Based on this model, the influences of different carrier injection barriers at the interface of the electrode/organic layer on the charge generation ability of interconnector layers were studied. In addition, the distribution characteristics of carrier concentration, electric field intensity and potential in the device under different carrier injection barriers were studied. The results show that when keeping one carrier injection barrier as a constant while increasing another carrier injection barrier, carri- ers injected into the device were gradually decreased, the carrier generation ability of the interconnector layer was gradually reduced, the electric field intensity at the interface of the organic/electrode was gradually enhanced, and the electric field distribution became nearly linear： the voltage drops in two light units gradually became the same. Meanwhile, the carrier injection ability decreased as another carrier injection barrier increased. The simulation re- sults agree with the experimental data. The obtained results can provide us with a deep understanding of the work mechanism of TMOs-based tandem OLEDs.

SOFC连接体表面层状钙钛矿氧化物涂层研究进展

固体氧化物燃料电池(SOFC)是现阶段非常具有应用前景的绿色发电系统。连接体是电池堆的重要组件之一,其性能优劣直接影响电池堆的性能和使用寿命。铁素体不锈钢是应用非常广泛的连接体材料,然而其高温抗氧化能力不足以及Cr元素的挥发严重制约燃料电池的长期稳定。本文介绍了作为连接体表面涂层的层状钙钛矿纳米氧化物的晶体结构、制备方法、合成工艺和保护机理,以及存在的问题和解决方案。