Hybrid Device of Blue GaN Light-Emitting Diodes and Organic Light-Emitting Diodes with Color Tunability for Smart Lighting Sources.

A lighting device with a wide color-tunable range is still a challenge for lighting based on either organic light-emitting diodes (OLEDs) or inorganic LEDs. In this work, we first proposed a novel hybrid device of organic LEDs and inorganic blue GaN LEDs to achieve full white and other colors. Organic LEDs were stacked with green and red emissive layers and connected with blue GaN LEDs in parallel but in opposite polarity voltage. Under the alternate-current (AC) driving, the hybrid structure can be controlled independently by applying timing variable opposite voltages to emit the light from either blue LEDs or the stacked OLEDs for forming mixed colors. The hybrid device can generate white light, varying in a wide range by changing the amplitude and duty ratio (DR) of AC-driving signals, from cold white to standard white and to warm white (3668-11 833 K). When an AC voltage of (4.80 V, -2.45 V) was applied, the device has a high color gamut of 95.24% National Television System Committee (NTSC) and a high color rendering index (R a) of 92.4%. The novel hybrid device with the blue LED and OLED in opposite polarity exhibits potential applications in smart solid-state lighting, display, and light communication.

Charge Modulation Layer and Wide-Color Tunability in a QD-LED with Multiemission Layers.

Widely tunable color emission from a single pixel is a promising but challenging technology for quantum-dot light-emitting diodes (QD-LEDs). Even a QD-LED pixel with stacked multi-QD layers having different colors is likely to emit a monotonic color because the exciton recombination mostly occurs in 1 or 1.5 QD layers with better charge balance. In this study, an all-solution-processed QD-LED with electrically tunable color emission over a wide color range by introducing a charge modulation layer (CML) is developed. Specifically, the CML acted as a high and narrow energy barrier for electrons between two QD layers, and the electron drift is sensitively controlled via the field-dependent tunneling effect. Therefore, the charge distribution and balance in the two QD layers re-electrically tunable, which enhanced the color tunability. The color tuning range and quantum efficiency are effectively controlled depending on the CML material and thickness. In addition, the color change caused by the solvent effect in a QD-LED with dual QD layers is thoroughly investigated. The proposed method may advance the understanding of QD emission behavior with the use of CML and provide a practical approach for the actual application of color-tunable pixel technology.

All-solution-processed colour-tuneable tandem quantum-dot light-emitting diode driven by AC signal.

We demonstrate a novel structure for a quantum-dot light-emitting diode (QD-LED) with wide-range colour-tuneable pixels, fabricated via full solution processing. The proposed device has a symmetrical structure produced via stacking of an inverted-structure diode with a green QD emission layer (EML) and normal-structure diode with a red QD EML. It is an electron-only device; however, a charge generation layer in the middle of the device generates holes for the formation of excitons. Depending on the polarity of the applied voltage, either the bottom inverted unit or the top normal unit is operated, thereby emitting green or red light, respectively. The working mechanism of the device is investigated via analysis of the charge generation mechanism and carrier transport path. In addition, the colour tunability is verified using a simple alternating current (AC) driving scheme; the duty cycle modulation of the AC signal enables fine colour adjustment over a broad range, from pure green to pure red. Thus, our colour-tuneable QD-LED with vertically stacked independently operated sub-pixels can open a promising pathway towards cost-effective ultra-high-resolution displays.

[Polymorphism in codons 10 and 25 of the transforming growth factor-beta1 gene in Korean population and in patients with liver cirrhosis and hepatocellular carcinoma].

BACKGROUND/AIMS: The genetic polymorphism of transforming growth factor-beta1 (TGF-beta1) at codons 10 and 25 which influences the production of TGF-beta1 is related to fibrogenesis in the lung and liver. We evaluated the genetic polymorphism at codons 10 and 25 in controls and in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC). METHODS: Blood samples were collected from controls (n=35), patients with LC (n=64), and HCC (n=49). Genomic DNA was isolated and polymerase chain reaction (PCR) was done for a segment including codons 10 and 25. The results of direct sequencing for PCR products were compared between the controls and the patients. RESULTS: There was no genetic polymorphism at codon 25 and three types of genetic polymorphism at codon 10. The leucine homozygous genotype (CTG/CTG) at codon 10 was more common in patients with LC than the controls (p=0.01) and especially in patients with LC caused by HBV (p=0.004). The polymorphism at codons 10 in patients with HCC was similar to the controls. However, leucine homozygous genotype was more common in patients with HCC of uninodular morphology than those of massive morphology (p=0.007). CONCLUSIONS: The genetic polymorphism of TGF-beta1 at codon 10 might be associated with LC and morphology of HCC. The potential usefulness of TGF-beta1 genotyping needs further studies in large scale.