In the fabrication of polymeric electroluminescent devices with indium-tin oxide (ITO) as anode, indium contamination of the polymers can greatly degrade the device performance. In the present study, we have used x-ray photoelectron spectroscopy to measure indium incorporation in poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate), referred to as PEDOT:PSS, which were spincast on bare ITO and encapsulated ITO. We found that the deposition of a self-assembled monolayer of alkylsiloxanes on ITO prior to spincasting PEDOT:PSS was effective and practical in blocking the reactions between ITO and PEDOT:PSS.

A series of robust, bulky and strongly emissive platinum(II) complexes supported by tetradentate O^N^C^N ligands with tert-butyl groups (1–4), a bridging tertiary amine (5) or a biphenyl group with a spiro linkage (6) at the periphery of the [O^N^C^N] ligand scaffold have been prepared. Their photophysical properties were examined by absorption and emission spectroscopy, density functional theory calculations, and ultra-fast time-resolved emission measurements. These complexes display emission quantum yields of up to 95%, with emission maxima λ_max in the range of 522 to 570 nm, and have a good thermal stability of up to T_d > 423 °C. Notably, the k_q values of 4–6 are in the range of 8.5 × 10⁶ to 2.0 × 10⁷ mol⁻¹ dm³ s⁻¹, smaller than those (∼10⁸ to 10⁹ mol⁻¹ dm³ s⁻¹) of other reported Pt(II) complexes. The bulky groups at the periphery of the [O^N^C^N] ligand disfavour intermolecular interactions and hence excimer formation in solutions. These complexes are good light-emitting materials (dopants) for OLEDs, since the triplet–triplet annihilation (TTA) and concentration quenching effect arising from intermolecular interactions can be minimized even at a high dopant concentration. The efficiency of the devices fabricated with 4–6 increased with dopant concentration up to a high level of 10% with no extra emitting component or significant shift in the CIE observed. The maximum power efficiency (PE) values achieved for the 5 (yellow-emitting) and 6 (green-emitting) based devices were 118 and 126 lm W⁻¹, respectively. These PE values are the highest among the reported Pt(II)-OLEDs and comparable to those of the best reported Ir(III)-OLEDs without the out-coupling technique. Complex 7 is structurally analogous to, but less bulky than 3–6 and is prone to giving excimer emission in the solid state. A high PE of up to 55.5 lm W⁻¹ and external quantum efficiency of up to 25.1% have been realized in the white OLEDs fabricated with 7 as a single emitting material. These values are comparable with those of the best reported WOLEDs based on a single emitting material.

Objectives: This in vitro study investigated the effects of silver diamine fluoride (SDF) on dentine carious lesion with cariogenic biofilm. Study Design: Thirty human dentine blocks were inoculated with Streptococcus mutans and Lactobacillus acidophilus dual-species biofilm to create carious lesion. They were equally divided into test and control group to receive topical application of SDF and water. After incubation anaerobically using micro-well plate at 37oC for 7 days, the biofilms were evaluated for kinetics, morphology and viability by colony forming units (CFU), scanning electron microscopy (SEM), and confocal microscopy (CLSM), respectively. The carious lesion underwent crystal characteristics analysis, evaluation of the changes in chemical structure and density of collagen fibrils using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and immune-labeling. Results: The log CFU of S. mutans and L. acidophilus in the test group was significantly lower than control group. SEM and CLSM showed confluent biofilm in control group, but not in test group. XRD showed the loss of crystallinity of dentine due to the dissolution of hydroxyapatite crystal structure in test group was less than control group. FTIR showed that log [Amide I: HPO42-] for test vs. control group was 0.31±0.10 vs. 0.57±0.13 (p<0.05). The gold-labeling density in test vs. control group was 8.54±2.44/µm2 vs. 12.91±4.24/µm2 (p=0.04). Conclusions: SDF had antimicrobial activity against the cariogenic biofilms and reduced demineralization of dentine.