The distribution of lithium between erythrocytes and plasma: in vitro studies on the transport of lithium in human erythrocytes

Distribution ratiors of intracellular lithium (Lii) and extracellular Li (Lie) were determined in vitro after incubation of Li-free or Li-loaded red cells in media containing varying Li-concentrations (37 degrees C, pH 7.4). The distribution ratios Lii/Lie obtained in vitro after 24 h of incubation corresponded to those found in vivo. The results indicate that Li can be extruded from red cells against an electrochemical gradient. This Li extrusion is inhibited by replacing extracellular Na+ with K+ or choline+, but is not affected by ouabain or by glucose depletion.     

Improved Performance and Stability of All‐Inorganic Perovskite Light‐Emitting Diodes by Antisolvent Vapor Treatment

All‐inorganic perovskite light‐emitting diodes (LEDs) reveal efficient luminescence with high color purity, but their modest brightness and poor stability are still critical drawbacks. Here, the luminescent efficiency and the stability of perovskite LEDs (PeLEDs) are boosted by antisolvent vapor treatment of CsPbBr₃ embedded in a dielectric polymer matrix of polyethylene oxide (PEO). A unique method is developed to obtain high quality CsPbBr₃ emitting layers with low defects by controlling their grain sizes. CsPbBr₃ in PEO matrix is post‐treated with antisolvent of chloroform (CF), leading to microcrystals with a size of ≈5 µm along the in‐plane direction with active emitting composite of 90%. A device based on CF post‐treatment (CsPbBr₃‐PEO‐CF) film displays a brightness of up to 51890 cd m^?2 with an external quantum efficiency of 4.76%. CsPbBr₃‐PEO‐CF PeLED still maintains 82% of its initial efficiency after 80 h continuous operation in ambient air, which indicates relatively good device stability. This work highlights that film quality is not only key to promoting fluorescence in CsPbBr₃, but also to achieving higher performance PeLEDs.     

Unraveling the Role of Substrates on Interface Energetics and Morphology of PCDTBT:PC70BM Bulk Heterojunction

In the pursuit of developing highly efficient polymer solar cells, it is indispensable to experimentally determine the molecular electronic and geometrical structures of distributed donor/acceptor bulk heterojunctions for understanding the processes inside the cell. In this article, substrate effect on interface energetics and film morphology of the poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)]:[6,6]‐phenyl‐C₇₀ butyric acid methyl ester (PCDTBT:PC₇₀BM) blends with various blending ratios on various conductive substrates is clarified based on the characterization of photoelectron spectroscopy and atomic force microscope, where the PCDTBT:PC₇₀BM blend film serves as an important model system due to efficient charge generation and transport with low recombination. The energetics of the PCDTBT:PC₇₀BM blend film is demonstrated to be highly dependent on the substrate work function, showing the transition from vacuum level alignment to Fermi level pinning with the variation of PC₇₀BM ratio in the blend film. The resulting morphology is in good agreement with the observed formation of a PCDTBT‐rich layer at the top of the PCDTBT:PC₇₀BM blend film irrespective of the variation of the PC₇₀BM blending ratio and annealing temperature. The results show the possibility of tuning the interfacial electronic structures by utilizing the substrate effects and potential applications on performance enhancement in polymer solar cells.     

Intrinsic Surface Dipoles Control the Energy Levels of Conjugated Polymers

Conjugated polymers are an important class of materials for organic electronics applications. There, the relative alignment of the electronic energy levels at ubiquitous organic/(in)organic interfaces is known to crucially impact device performance. On the prototypical example of poly(3‐hexylthiophene) and a fluorinated derivative, the energies of the ionization and affinity levels of π‐conjugated polymers are revealed to critically depend on the orientation of the polymer backbones with respect to such interfaces. Based on extensive first‐principles calculations, an intuitive electrostatic model is developed that quantitatively traces these observations back to intrinsic intramolecular surface dipoles arising from the π‐electron system and intramolecular polar bonds. The results shed new light on the working principles of organic electronic devices and suggest novel strategies for materials design.     

Orientation-dependent ionization energies and interface dipoles in ordered molecular assemblies

Although an isolated individual molecule clearly has only one ionization potential, multiple values are found for molecules in ordered assemblies. Photoelectron spectroscopy of archetypical pi-conjugated organic compounds on metal substrates combined with first-principles calculations and electrostatic modelling reveal the existence of a surface dipole built into molecular layers. Conceptually different from the surface dipole at metal surfaces, its origin lies in details of the molecular electronic structure and its magnitude depends on the orientation of molecules relative to the surface of an ordered assembly. Suitable pre-patterning of substrates to induce specific molecular orientations in subsequently grown films thus permits adjusting the ionization potential of one molecular species over up to 0.6 eV via control over monolayer morphology. In addition to providing in-depth understanding of this phenomenon, our study offers design guidelines for improved organic-organic heterojunctions, hole- or electron-blocking layers and reduced barriers for charge-carrier injection in organic electronic devices.