As eries of rigid nonconjugated polyimide (PI)based thermally activated delayed fluorescence (TADF) polymers were reported for the first time,b ased on a" TADF-Linker-Host" strategy.A mong of which,t he TADF unit contains at ypical TADF luminous core structure,t he "Host" unit exhibits effective conjugation length that endows polyimide with high triplet energy,a nd the "Linker" unit has an aliphatic ring structure to improve solubility and inhibits intramolecular charge transfer effect. All the TADF polymers exhibit high thermal stability (T g > 308.7 8 8C) and refractive index (1.76-1.79). Remarkably,highly-efficient polymer lightemitting diodes (PLEDs) based on the polymers are successfully realized, leading to am aximal external quantum efficiency of 21.0 %a long with lowe fficiency roll-off.S uch outstanding efficiency is amongst the state-of-the-art performance of nonconjugated PLEDs,confirming the effectiveness of structural design strategy,p roviding helpful and valuable guidance on the development of highly-efficient fluorescent polymer materials and PLEDs.

physics, and engineering. One of the key points lies in the development of flexible substrate materials and efficient packaging technology. The components of organic light-emitting devices (OLEDs) or organic photovoltaics (OPV), including the cathode materials and photoelectric conversion layer, are reactive; thus, thin films should encapsulate both the top and bottom surfaces of the devices to realize the desired property. [2-4] Barrier-coated plastic lids, ultrathin glasses, and vacuumdeposited thin films have been developed as thin-film encapsulation (TFE) approaches. [5] However, there are many issues with the current manufacturing methods for encapsulation films. The laser lift-off (LLO) process is widely used for flexible electronics manufacturing, requires evaporating each functional layer onto a substrate, then peeling the devices off the substrate using a laser; the product yield is high, but the productivity is low. In contrast, roll-to-roll (R2R) processing, which involves directly assembling the devices on a formed substrate, is more suitable for large-scale industrial production. [6,7] There are demanding performance requirements for the encapsulation film, such as light transmittance, flexibility, gas impermeability, and heat resistance. The encapsulation film in the direction of light transmission should be highly transparent. [8,9] The other functional layers in electronic devices can be fabricated with nanoscale thickness; thus, the flexibility of the completed devices mainly depends on the properties of the encapsulation materials. Encapsulation materials have gradually developed from rigid glass plates to flexible thin films in recent years. [6,10] The degree of gas permeability is the most important property of TFE materials because flexible electronics use reactive metals and organic matters in devices. It is generally required that the water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) should be on the order of 10 −3-10 −6 g m −2 day −1 to provide flexible electronics to have a sufficient service life. [11,12] Furthermore, OLEDs, for example, use thin-film transistors (TFTs) to control brightness and grayscale. A flat/smooth surface (roughness average R a < 1 nm) is beneficial for the fabrication of its nanostructures, and as the manufacturing temperature of TFTs is very high, A good packing of flexible electronics is one of the most critical points to ensure its lifetime. However, efficient and straightforward packaging technology is still very challenging. In this work, a new strategy for preparing encapsulation film is reported by "enameling" a fusible glass layer on a polymer membrane. Careful consideration has been given to the materials properties and manufacturing process, and the obtained glass-coated polymer can combine the advantageous properties of polymers and inorganic materials unconventionally. The encapsulation films show exceptional overall properties, including transparency (<5% optical deterioration), flexibility (radius of curvature: 1.5 mm), and low ...

An efficient chemo/regio/stereoselective synthesis of novel and functionalized spiro-oxindole/pyrrolizine/ pyrrolidine scaffolds has been achieved. The in situ generated azomethine ylide from isatin & L-proline/ phenyl alanine underwent 1,3-dipolar cycloaddition with a-aroylidineketene dithioacetals under simple reaction conditions affording spiro-oxindole derivatives. This protocol exhibits an interesting double bond selectivity of a-aroylidineketene dithioacetals. Furthermore, utilizing this spiro-oxindoles scaffold, biologically important benzimidazole and pyrimidine based poly heterocycles were also synthesized.

A synthesis of γ,δ‐unsaturated β‐ketothiolester depend on the properties of solvent and their relative humidity. γ,δ‐unsaturated β‐ketothiolester shows solvent dependent emission due to excited state intramolecular proton transfer (ESIPT). Increasing solvent polarity makes larger Stokes’ shifts ranging from 4072 to 6459 cm−1. γ,δ‐unsaturated β‐ketothiolester exhibit red‐shifted emission (591 nm) in the solid state than the solution. In THF‐H2O mixture, solvent polarity parameter (Δf) increases by increasing H2O ratio (0‐90%) where aggregation‐induced emission enhancement (AIEE) of γ,δ‐unsaturated β‐ketothiolester enhanced by increasing Δf. The Intermolecular interaction by polar protic solvent with γ,δ‐unsaturated β‐ketothiolester is the response for decrease in emission above 60% H2O in THF‐H2O mixture. Picric acid detection of γ,δ‐unsaturated β‐ketothiolester enhanced by AIEE with a detection limit of 2 μM. Emission quenching mechanism was identified using NMR technique. Selective detection of picric acid is high when with compared to other nitroaromatic compounds and act as a inexpensive test strip detector for picric acid.