Quantum efficiencies of organic-inorganic hybrid lead halide perovskite light-emitting devices (LEDs) have increased significantly, but poor device operational stability still impedes their further development and application. All-inorganic perovskites show better stability than the hybrid counterparts, but the performance of their respective films used in LEDs is limited by the large perovskite grain sizes, which lowers the radiative recombination probability and results in grain boundary related trap states. We realize smooth and pinhole-free, small-grained inorganic perovskite films with improved photoluminescence quantum yield by introducing trifluoroacetate anions to effectively passivate surface defects and control the crystal growth. As a result, efficient green LEDs based on inorganic perovskite films achieve a high current efficiency of 32.0 cd A−1 corresponding to an external quantum efficiency of 10.5%. More importantly, our all-inorganic perovskite LEDs demonstrate a record operational lifetime, with a half-lifetime of over 250 h at an initial luminance of 100 cd m−2.

Shell is of great significance to the enhancement in the photoluminescence quantum yield (PLQY) and stability of core–shell-type quantum dots (QDs). InP/ZnS core–shell QDs without intrinsic toxicity have shown huge potential as a replacement for the widely used cadmium-containing QDs; however, it is still challenging to control the growth of InP-based core–shell QDs due to the lattice mismatch between the InP core and ZnS shell. Here, we report on the synthesis of ∼15-nm-size InP/ZnSe/ZnS QDs with a thick ZnS outer shell by a layer-by-layer shell growth strategy. The ZnS shell was prepared by a circularly gradient temperature rise and long reaction procedure in each step, which not only ensures relatively low precursor concentration preventing the anisotropic growth of QDs but also allows the low-reactivity source to be decomposed sufficiently to achieve layer-by-layer growth of a thick ZnS shell. The resulting QDs show the highest PLQY of 73%, narrow emission line width of up to 40 nm, wide spectrum tunability, and excellent stability. Furthermore, the thick ZnS shell also effectively suppresses nonradiative Förster resonant energy transfer and Auger recombination within QDs. As a result, these enable our quantum dot light-emitting diodes (QLEDs) to achieve a record external quantum efficiency of 6.6% in heavy-metal-free red QLEDs.

The unstable nature of perovskites has severely limited their practical applications. Here, we report on ultrastable CsPbBr3 nanocrystals (NCs) with a thick (∼25 nm) polymer coating prepared via an effective postsynthetic strategy. The thick poly­(maleic anhydride-alt-1-octadecene) (PMAO) with long hydrophobic alkyl chains bounded with the surface ligands of perovskite NCs acts as a protection layer to effectively prevent perovskite degradation from the external environment. The photoluminescence (PL) for the thick PMAO-coated CsPbBr3 NCs maintains more than 90% of its initial emission intensity under continuous ultraviolet illumination of 144 h, whereas that of the pristine NCs is decreased to ∼6%. After exposure in air for 40 days, only a very little PL degradation appears for the thick polymer-coated NCs as compared to the dramatic decrease in the PL emission for the pristine NCs. Upon immersion into water for 24 h, the perovskite NCs maintain 60% of its initial PL intensity, whereas the PL emission for the pristine NCs is completely quenched within only a few minutes. Moreover, there is no any side effect on the luminescent properties of perovskite NCs by the transparent polymer coating and the PL quantum yields are obviously improved due to the surface defect passivation of NCs. The resulting thick PMAO-coated CsPbBr3 NCs are combined with a commercially available red-emitting phosphor on a blue InGaN chip to fabricate a high-performance warm white light-emitting diode with a high power efficiency of 56.6 lm/W.

The poor understanding of HONO sources in the daytime highlights the importance of the heterogeneous photochemical reaction of NO2 with aerosol or soil surfaces. The conversion of NO2 to HONO on humic acid (HA) under simulated sunlight was investigated using a flow tube reactor at ambient pressure. The uptake coefficient (γ) of NO2 linearly increased with irradiation intensity and HA mass in the range of 0-2.0 μg/cm(2), while it decreased with the NO2 concentration. The HONO yield was found to be independent of irradiation intensity, HA mass, and NO2 concentration. The temperature (278-308 K) had little influence on both γ and HONO yield. Additionally, γ increased continuously with relative humidity (RH, 7-70%), and a maximum HONO yield was observed at 40% RH. The heterogeneous photochemical reaction of NO2 with HA was explained by the Langmuir-Hinshelwood mechanism.

A novel series of tertiary amines as retinoid-related orphan receptor gamma-t (RORγt) inverse agonists was discovered through agonist/inverse agonist conversion. The level of RORγt inhibition can be enhanced by modulating the conformational disruption of H12 in RORγt LBD. Linker exploration and rational design led to the discovery of more potent indole-based RORγt inverse agonists.KEYWORDS: RORγt, agonists, inverse agonists, Th17 cell differentiation, cocrystal structure, structure-based design R etinoid-related orphan receptor gamma-t (RORγt) is a member of the nuclear receptor superfamily. RORγt is a key regulator of the development and functions of T-helper 17 (Th17) cells which are implicated in the pathology of a variety of human inflammatory and autoimmune disorders. 1,2 The RORγt inhibitors have potential utility in controlling the activity of Th17 cells and can be developed as therapeutic agents for treatment of Th17-related autoimmune diseases. A few small molecule inhibitors of RORγt have been reported in the literature. 3−10 In this paper, we report the discovery of tertiary amines and indoles as potent RORγt inverse agonists using structure-and knowledge-based compound design.A high-throughput screen (HTS) of the GSK in-house compound collection using a RORγ fluorescence resonance energy transfer (FRET) assay 11 resulted in identification of thiazole amide 1 as a RORγt inverse agonist with IC 50 of 1.0 μM. The binding of 1 to the RORγt ligand binding domain (LBD) was confirmed with a thermal shift of 7.1°C in a thermal shift assay. 11 SAR exploration on the left-hand side (LHS) of 1 led to the identification of tertiary amine 2 as a potent RORγt agonist with a EC 50 of 0.02 μM in dual FRET assay (Scheme 1). 12 Dual FRET assay, using the same technology as the FRET assay but without adding a surrogate agonist, only relies on the basal level of RORγt activity and is able to measure both agonists and inverse agonists. Peptide profiling study using dual FRET assay showed that coactivator peptide (e.g., steroid receptor coactivator 1 (SRC1)) was recruited upon binding of 2 to RORγt LBD whereas corepressor peptide (e.g., nuclear receptor corepressor 2 (NCOR2)) was not. 12 Given the structure similarity of 1 and 2, we assume that they adopt a similar binding mode within RORγt LBD despite their difference as agonist and inverse agonist. To understand the binding mode of the chemical series, an in-silico docking study for 2 based on a reported RORγt crystal structure 13 was conducted.A RORγt LBD crystal structure (PDB accession code: 3KYT) was selected and processed for the docking study. A total of 40 poses with the best scores were obtained and visually inspected after docking with Surflex-Dock v2.3 14−16 in Sybyl 8.1, 17 among which the top 10 poses were found to be representative and thus further ranked using MM/GBSA 18−20 affinity scores based on the VSGB2.0 solvent model. 21,22 As a