Ligand Exchange of Colloidal ZnO Nanocrystals from the High Temperature and Nonaqueous Approach

Colloidal zinc oxide(ZnO) nanocrystals generated from the high temperature and nonaqueous approache are attractive for use in solution-processed electrical and optoelectronic devices. However, the asprepared colloidal ZnO nanocrystals by this approach are generally capped by ligands with long alkyl-chains,which is disadvantage for solution-processed devices due to hindering charge transport. Here we demonstrate an effective ligand exchange process for the colloidal ZnO nanocrystals from the high temperature and nonaqueous approach by using n-butylamine. The ligand exchange process was carefully characterized. The thin films based on colloidal ZnO nanocrystals after ligand exchange exhibited dramatically enhanced UV photoconductivity.

双层膦氧化物分子修饰制备高效的大面积纯蓝光钙钛矿量子点发光二极管

蓝光卤素钙钛矿发光二极管(LED)由于其高色纯度和全色钙钛矿LED发展需求目前受到越来越多的关注.通过钝化卤素钙钛矿中的缺陷来提高LED性能是主要研究方向,然而,用于有效钝化混合卤素蓝光钙钛矿并获得性能优异、光谱稳定的纯蓝光LED方法还很有限.本文开发了一种使用含有膦氧基团的双层有机分子对混合卤素蓝光钙钛矿量子点进行固相修饰,不仅有效提高了量子点薄膜的发光性能,而且有效改善了LED的电荷平衡,显著提高了器件性能,获得了最大外量子效率为4.87%的纯蓝光LED(469 nm).作者发现双层膦氧分子与量子点之间可以发生强相互作用,从而有效钝化量子点,并有助于获得大面积单层钙钛矿量子点薄膜.其中,发光面积为64 mm2,波长为469 nm的LED最大外量子效率为3.91%.本文所述策略有助于推动性能优异的大面积钙钛矿量子点光电器件开发.

Highly spectra-stable pure blue perovskite light-emitting diodes based on copper and potassium co-doped quantum dots

Halide perovskite light emitting diodes(LEDs)have gained great progress in recent years.However,mixed-halide perovskites for blue LEDs usually suffer from electroluminescence(EL)spectra shift at a high applied voltage or current density,limiting their efficiency.In this work,we report a strategy of using single-layer perovskite quantum dots(QDs)film to tackle the electroluminescence spectra shift in pure-blue perovskite LEDs and improve the LED efficiency by co-doping copper and potassium in the mixed-halide perovskite QDs.As a result,we obtained pure-blue halide perovskite QD-LEDs with stable EL spectra centred at 469 nm even at a current density of 1,617 mA·cm^(−2).The optimal device presents a maximum external quantum efficiency(EQE)of 2.0%.The average maximum EQE and luminance of the LEDs are 1.49%and 393 cd·m^(−2),increasing 62%and 66%compared with the control LEDs.Our study provides an effective strategy for achieving spectra-stable and highly efficient pure-blue perovskite LEDs.

MAGED4B Promotes Glioma Progression via Inactivation of the TNF-α-induced Apoptotic Pathway by Down-regulating TRIM27 Expression

MAGED4B belongs to the melanoma-associated antigen family;originally found in melanoma,it is expressed in various types of cancer,and is especially enriched in glioblastoma.However,the functional role and molecular mechanisms of MAGED4B in glioma are still unclear.In this study,we found that the MAGED4B level was higher in glioma tissue than that in non-cancer tissue,and the level was positively correlated with glioma grade,tumor diameter,Ki-67 level,and patient age.The patients with higher levels had a worse prognosis than those with lower MAGED4B levels.In glioma cells,MAGED4B overexpression promoted proliferation,invasion,and migration,as well as decreasing apoptosis and the chemosensitivity to cisplatin and temozolomide.On the contrary,MAGED4B knockdown in glioma cells inhibited proliferation,invasion,and migration,as well as increasing apoptosis and the chemosensitivity to cisplatin and temozolomide.MAGED4B knockdown also inhibited the growth of gliomas implanted into the rat brain.The interaction between MAGED4B and tripartite motif-containing 27(TRIM27)in glioma cells was detected by co-immunoprecipitation assay,which showed that MAGED4B was co-localized with TRIM27.In addition,MAGED4B overexpression down-regulated the TRIM27 protein level,and this was blocked by carbobenzoxyl-L-leucyl-L-leucyl-L-leucine(MG132),an inhibitor of the proteasome.On the contrary,MAGED4B knockdown up-regulated the TRIM27 level.Furthermore,MAGED4B overexpression increased TRIM27 ubiquitination in the presence of MG132.Accordingly,MAGED4B down-regulated the protein levels of genes downstream of ubiquitin-specific protease 7(USP7)involved in the tumor necrosis factor-alpha(TNF-α)-induced apoptotic pathway.These findings indicate that MAGED4B promotes glioma growth via a TRIM27/USP7/receptor-interacting serine/threonine-protein kinase 1(RIP1)-dependent TNF-α-induced apoptotic pathway,which suggests that MAGED4B is a potential target for glioma diagnosis and treatment.

Ultrastable and highly efficient CsPbBr_(3) composites achieved by dual-matrix encapsulation for display devices

Perovskite nanocrystals(NCs)with high stabilities and excellent optical perfor-mances are crucial for display applications.However,to date,perovskite emitters with both high photoluminescence(PL)quantum yield(PLQY)and high stabili-ties under harsh synergistic humidity–heat–light aging conditions have not been reported.The promising high-temperature solid-state sintering with single oxide matrices cannot ensure high PLQY and synergistic aging stabilities of perovskites.Herein,both the PLQY and overall(thermal,moisture,and photo)stabilities of all-inorganic perovskite(CsPbBr_(3))NCs are improved by dual-matrix encapsula-tion,which is accomplished by in situ crystallization of CsPbBr_(3)@Cs_(4)PbBr_(6)nanocomposites in silica molecular sieve(MS)templates via advanced solid-state synthesis a using precisely controlled molar ratio of precursor components and cooling rates.The Cs_(4)PbBr_(6)matrix effectively passivates the surfaces of CsPbBr_(3)NCs,and the MS matrix insulates CsPbBr_(3)@Cs_(4)PbBr_(6)from the external environ-ment.The resulting CsPbBr_(3)@Cs_(4)PbBr_(6)/MS composites exhibit the highest PLQY(>90%)among those of the solid-state perovskite NCs and significant stabilities against water,heat,and blue light irradiation,maintaining more than 80%of their initial PL intensities after being aged for 1000 h under synergistic high-humidity(85%),high-temperature(85C),and strong blue light irradiation(350 mW cm2)conditions.To the best of our knowledge,these CsPbBr_(3)@Cs_(4)PbBr_(6)/MS composites represent the most stable perovskite emitters under synergistic humidity–heat–light aging conditions.The liquid crystal display backlight module fabricated using these stable composites demonstrates a wide color gamut of 131%of the National Television Standards Committee standard.We speculate that this dual-matrix encapsulation can be used for industrial mass production.

Highly-efficient thermoelectric-driven light-emitting diodes based on colloidal quantum dots

Driven by sub-bandgap electric work and Peltier heat,thermoelectric-driven light-emitting diodes(TED-LEDs)not only offer much enhanced power-conversion-efficiency but also eliminate the waste heat generated during the operation of LEDs.However,costeffective and high-efficiency TED-LEDs are not readily accessible for the epitaxially grown III-V LEDs due to the high chip cost and efficiency droop at low-medium brightness(current densities).Here we show that electroluminescence of colloidal quantum dots(QDs)LEDs(QLEDs)circumvents the deficiencies faced by conventional LEDs.The optimal red-emitting device fabricated by cost-effective solution processing technics exhibits external-and internal-power-conversion-efficiency of 21.5%and 93.5%at 100 cd/m^(2),suited for high-efficiency solid-state lighting and high-resolution display.At this brightness,the electric driving voltage(V)of 1.89 V is lower than the photon voltage(Vp=hv/q=1.96 V,q being the elemental charge).With typical Vp=1.96 V,electroluminescence can be detected with the driving voltage as low as 1.0-1.2 V.Luminance of the thermoelectric-driven QLEDs(TED-QLEDs)remains ideally diffusion-dominated with the driving voltage lower than~1.5 V,and further improvement on charge transport is expected to extend the linear ideality to all practical driving voltages.

Preliminary analysis of cellular sociology of co-cultured glioma initiating cells and macrophages in vitro

Objective: Real-time monitoring of cytokine secretion at the single immunocyte level,based on the concept of immune cells, sociology has been recently reported. However,the relationships between glioma-initiating cells(GICs) and host immune cells and their mutual interactions in the tumor microenvironment have not been directly observed and remain unclear. Methods: The dual fluorescence tracing technique was applied to label the co-cultured GICs and host macrophages(M?), and the interactions between the two types of cells were observed using a live cell imaging system. Fusion cells in the co-culture system were monocloned and proliferated in vitro and their social interactions were observed and recorded. Results: Using real-time dynamic observation of target cells, 6 types of intercellular conjunction microtubes were found to function in the transfer of intercellular information between GICs and M?; GICs and host M? can fuse into hybrid cells after several rounds of mutual interactions, and then these fusion cells fused with each other; Fusion cells generated offspring cells through symmetrical and asymmetrical division or underwent apoptosis. A "cell in cell" phenomenon was observed in the fusion cells, which was often followed by cell release, namely entosis. Conclusions: Preliminary studies revealed the patterns of cell conjunction via microtubes between GICs and host M? and the processes of cell fusion, division, and entosis. The results revealed malignant transformation of host M?, induced by GICs, suggesting complex social relationships among tumor-immune cells in gliomas.

Efficient and bright broadband electroluminescence based on environmentfriendly metal halide nanoclusters

Broadband electroluminescence based on environment-friendly emitters is promising for healthy lighting yet remains an unprecedented challenge to progress.The copper halide-based emitters are competitive candidates for broadband emission,but their high-performance electroluminescence shows inadequate broad emission bandwidth of less than 90 nm.Here,we demonstrate efficient ultra-broadband electroluminescence from a copper halide(CuI)nanocluster single emitter prepared by a one-step solution synthesis-deposition process,through dedicated design of ligands and subtle selection of solvents.The CuI nanocluster exhibits high rigidity in the excitation state as well as dual-emissive modes of phosphorescence and temperature-activated delayed fluorescence,enabling the uniform cluster-composed film to show excellent stability and high photoluminescent efficiency.In consequence,ultra-broadband light-emitting diodes(LEDs)present nearly identical performance in an inert or air atmosphere without encapsulation and outstanding high-temperature operation performance,reaching an emission full width at half maximum(FWHM)of~120 nm,a peak external quantum efficiency of 13%,a record maximum luminance of~50,000 cd m^(−2),and an operating half-lifetime of 137 h at 100 cd m^(−2).The results highlight the potential of copper halide nanoclusters for next-generation healthy lighting.