Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone

ZnTeSe quantum dots(QDs),recognized as promising eco-friendly blue electroluminescent emitters,remain under-explored in light-emitting diode(LED)applications.Here,to elucidate the operation and degradation mechanisms of ZnTeSe blue QD-LEDs,stacked ZnTeSe QD layers with discernable luminescence are designed by varying Te doping concentrations,and the recombination zones(RZs)of the blue QD-LEDs are investigated.The RZs are identified near the hole-transport layer(HTL),confirmed by angular-dependent electroluminescence measurements and optical simulations.In addition,in order to investigate carrier dynamics in the process of recombination,the transient electroluminescence(tr-EL)signals of the dichromatic QD-LEDs are analyzed.As a result,it is inferred that the RZ initially formed near the electron-transport layer(ETL)due to the high injection barriers of electrons.However,due to the fast electron mobility,the RZ shifts toward the HTL as the operating current increases.After the device lifetime tests,the RZ remains stationary while the photoluminescence(PL)corresponding to the RZ undergoes a substantial decrease,indicating that the degradation is accelerated by the concentrated RZ.Thus this study contributes to a deeper understanding of the operational mechanisms of ZnTeSe blue QD-LEDs.

A bioactive compliant vascular graft modulates macrophage polarization and maintains patency with robust vascular remodeling

Conventional synthetic vascular grafts are associated with significant failure rates due to their mismatched mechanical properties with the native vessel and poor regenerative potential.Though different tissue engineering approaches have been used to improve the biocompatibility of synthetic vascular grafts,it is still crucial to develop a new generation of synthetic grafts that can match the dynamics of native vessel and direct the host response to achieve robust vascular regeneration.The size of pores within implanted biomaterials has shown significant effects on macrophage polarization,which has been further confirmed as necessary for efficient vascular formation and remodeling.Here,we developed biodegradable,autoclavable synthetic vascular grafts from a new polyurethane elastomer and tailored the grafts’interconnected pore sizes to promote macrophage populations with a pro-regenerative phenotype and improve vascular regeneration and patency rate.The synthetic vascular grafts showed similar mechanical properties to native blood vessels,encouraged macrophage populations with varying M2 to M1 phenotypic expression,and maintained patency and vascular regeneration in a one-month rat carotid interposition model and in a four-month rat aortic interposition model.This innovative bioactive synthetic vascular graft holds promise to treat clinical vascular diseases.

Hybridisation of perovskite nanocrystals with organic molecules for highly efficient liquid scintillators

Compared with solid scintillators,liquid scintillators have limited capability in dosimetry and radiography due to their relatively low light yields.Here,we report a new generation of highly efficient and low-cost liquid scintillators constructed by surface hybridisation of colloidal metal halide perovskite CsPbA_(3)(A:Cl,Br,I)nanocrystals(NCs)with organic molecules(2,5-diphenyloxazole).The hybrid liquid scintillators,compared to state-of-the-art CsI and Gd_(2)O_(2)S,demonstrate markedly highly competitive radioluminescence quantum yields under X-ray irradiation typically employed in diagnosis and treatment.Experimental and theoretical analyses suggest that the enhanced quantum yield is associated with X-ray photon-induced charge transfer from the organic molecules to the NCs.High-resolution X-ray imaging is demonstrated using a hybrid CsPbBr_(3) NC-based liquid scintillator.The novel X-ray scintillation mechanism in our hybrid scintillators could be extended to enhance the quantum yield of various types of scintillators,enabling low-dose radiation detection in various fields,including fundamental science and imaging.