Pentacene-Based Thin-Film Transistors With a Solution-Process Hafnium Oxide Insulator

Abstract—Pentacene-based organic thin-film transistors with solution-process hafnium oxide (HfOx) as gate insulating layer have been demonstrated. The solution-process HfOx could not only exhibit a high-permittivity (κ = 11) dielectric constant but also has good dielectric strength. Moreover, the root-mean-square surface roughness and surface energy (γs) on the surface of the HfOx layer were 1.304 nm and 34.24 mJ/cm2, respectively. The smooth, as well as hydrophobic, surface of HfOx could facilitate the direct deposition of the pentacene film without an additional polymer treatment layer, leading to a high field-effect mobility of 3.8 cm2/(V · s). Index Terms—Hafnium oxide, high permittivity, organic thinfilm transistor (OTFT), solution process, surface energy

Enhancing Color Purity and Stable Efficiency of White Organic Light Diodes by Using Hole-Blocking Layer

The organic light-emitting diodes with triple hole-blocking layer (THBL) formation sandwich structure which generate white emission were fabricated. The 5,6,11,12-tetraphenylnapthacene (Rubrene), (4,4′-N,N′-dicarbazole)biphenyl (CBP), and 4,4′-bis(2,2′diphenylvinil)-1,1′-biphenyl (DPVBi) were used as emitting materials in the device. The function of CBP layer is not only an emitting layer but also a hole-blocking layer (HBL), and the Rubrene was doped into the CBP. The optimal configuration structure was indium tin oxide (ITO)/Molybdenum trioxide (MoO3) (5 nm)/[4,4-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB) (35 nm)/CBP (HBL1) (5 nm)/DPVBi (I) (10 nm)/CBP (HBL2) : Rubrene (4 : 1) (3 nm)/DPVBi (II) (30 nm)/CBP (HBL3) (2 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen) (10 nm)/Lithium fluoride (LiF)/aluminum (Al). The result showed that the device with Rubrene doped in CBP (HBL2) exhibited a stable white emission with the color coordinates of (0.322, 0.368), and the coordinate with the slight shift of ±Δx,y = (0.001, 0.011) for applied voltage of 8–12 V was observed

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

The Investigation of High Quality PEDOT:PSS Film by Multilayer-Processing and Acid Treatment

In this study, we have investigated the performance of multilayer films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) treated with one of the perfluorinated carboxylic acids, named trifluoroacetic acid (TFA). According to the increased density of the PEDOT chain under unit area conditions, the sheet resistance (Rsq) has improved from 300 to 65 Ω/sq through additional processing of PEDOT:PSS from single layer to multilayer. After the further treatment with TFA, however, the Rsq of the multilayer PEDOT:PSS was enhanced to 45 Ω/sq, leading to the decline of film thickness from 400 to 270 nm. Both conductivity and work function based on X-ray photoelectron spectroscopy results have built a breakthrough by double-processing because of the higher density of conductive PEDOT chains and the increase of 0.4 eV alternatives to typical indium tin oxide substrate, respectively. This improvement is contributed to the development of more effective transparent electrodes

Enhancing Color Purity and Stable Efficiency of White Organic Light Diodes by Using Hole-Blocking Layer

The organic light-emitting diodes with triple hole-blocking layer (THBL) formation sandwich structure which generate white emission were fabricated. The 5,6,11,12-tetraphenylnapthacene (Rubrene), (4,4 -N,N -dicarbazole)biphenyl (CBP), and 4,4 -bis(2,2 diphenylvinil)-1,1 -biphenyl (DPVBi) were used as emitting materials in the device. The function of CBP layer is not only an emitting layer but also a hole-blocking layer (HBL), and the Rubrene was doped into the CBP. The optimal configuration structure was indium tin oxide (ITO)/Molybdenum trioxide (MoO 3 ) (5 nm)/[4,4-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB) (35 nm)/CBP (HBL1) (5 nm)/DPVBi (I) (10 nm)/CBP (HBL2) : Rubrene (4 : 1) (3 nm)/DPVBi (II) (30 nm)/CBP (HBL3) (2 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen) (10 nm)/Lithium fluoride (LiF)/aluminum (Al). The result showed that the device with Rubrene doped in CBP (HBL2) exhibited a stable white emission with the color coordinates of (0.322, 0.368), and the coordinate with the slight shift of ±Δ , = (0.001, 0.011) for applied voltage of 8-12 V was observed

The Effects of Dilute Sulfuric Acid on Sheet Resistance and Transmittance in Poly(3,4-thylenedioxythiophene): Poly(styrenesulfonate) Films

The conductivity of poly(3,4-thylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) films by adding various molar concentrations of sulfuric acid (H2SO4) was improved and studied in this paper. The sheet resistance of the doped PEDOT: PSS film was enhanced with increasing the ratio of H2SO4, but it drops after the maximum sheet resistance. The reason for this phenomenon is resulting from the fact that the H2SO4 preferentially react with the sorbitol which is so-called the pinacol rearrangement. The nonconductive anions of some PSS− were substituted by the conductive anions of hydrogen sulfate (HSO4-) when the residual H2SO4 reacted with PSS. In addition to the substitution reaction, PEDOT chains were increasingly aggregated with increasing the ratio of H2SO4. After doped H2SO4, the sheet resistance of H2SO4-doped PEDOT: PSS film is improved nearly 36%; the surface roughness is reduced from 1.268 nm to 0.822 nm and the transmittance is up to 91.9% in the visible wavelength range from 400 to 700 nm