High Efficiency and Stable Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence Emitter

High efficiency, stable organic light-emitting diodes （OLEDs） based on 2-pheyl-4＇-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide （TXO-PhCz） with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer （EML） show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency （EQE） of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time （LTSO） of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris（2-phenylpyridinato）iridium（ Ⅲ） （Ir（ppy）a）. These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz.

Highly Efficient and Stable Hybrid White Organic Light Emitting Diodes with Controllable Exciton Behavior by a Mixed Bipolar Interlayer

Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.

Constructing robust all-inorganic contacts enable stable perovskite solar cells with efficiencies over 20%

Developing photovoltaic(PV)cells for harvesting renewable and clean solar energy is a promising strategy to meet the growing energy demand.Perovskite solar cells(PSCs),as a new player in the photovoltaic field,exhibit rapid development with an original power conversion efficiency(PCE)of 3.81%in 2009,a promising PCE of over 20%in 2014 and a record PCE of 22.1%in

Screening Chinese soybean genotypes for Agrobacterium-mediated genetic transformation suitability

The Agrobacterium-mediated transformation system is the most commonly used method in soybean transformation.Screening of soybean genotypes favorable for Agrobacterium-infection and tissue regeneration is the most important step to establish an efficient genetic transformation system.In this study,twenty soybean genotypes that originated from different soybean production regions in China were screened for transient infection,regeneration capacity,and stable transgenic efficiency.Three genotypes,Yuechun 04-5,Yuechun 03-3,and Tianlong 1,showed comparable stable transgenic efficiencies with that of the previously reported American genotypes Williams 82 and Jack in our experimental system.For the Tianlong 1,the average stable transformation efficiency is 4.59%,higher than that of control genotypes(Jack and Williams 82),which is enough for further genomic research and genetic engineering.While polymerase chain reaction(PCR),LibertyLink strips,and β-glucuronidase(GUS) staining assays were used to detect the insertion and expression of the transgene,leaves painted with 135 mg/L Basta could efficiently identify the transformants.

Numerical and Performance Analysis of one row Transonic Rotor with Sweep and Lean angle

In this study,aerodynamic behaviors of swept and leaned blades were investigated.Axial and tangential blade curvatures impacts on compressor's operating parameters were analyzed separately.A commercial CFD program which solves the Reynolds-averaged Navier-Stokes equations was used to find out the mentioned impact and the complicated flow field of transonic compressor-rotors.The CFD method that was used for solving flow field's equation was validated by experimental data of NASA Rotor 67.The results showed that the compressor with curved rotors had higher efficiency,rotor pressure ratio and stable operating range compared to the compressor with un-curved rotors.Using curved rotors mostly had higher impact on the overall stable operating range compared to the other operating parameters.Operating range involves choking point and stall point that were changed separately by using of bended blade.For finding the detailed impact of sweep and lean angle on transonic blades,various forms of lean and sweep angles were exerted to basic rotor.It was found that sweep angles increased overall operating range up to 30%,efficiency up to 2%and pressure ratio up to 1%.Leaning the blades increased the safe operating range,the pressure ratio and efficiency by 14%,4%and 2%respectively.