Publications by authors named "Cao Weiran"

The electroluminescence performance of heavy-metal-free blue quantum dot (QD) light-emitting diodes (QLEDs) is much lower than that of state-of-the-art cadmium-based counterparts. Ecofriendly ZnSeTe QDs are an ideal alternative to cadmium-based blue QDs, but face issues with colour impurity and inferior stability caused by the aggregated tellurium (Te) that dominates compositional inhomogeneity. Here we developed an isoelectronic control strategy using congeneric sulfur coordinated with triphenyl phosphite (TPP-S) to construct homogeneous ZnSeTeS QDs with pure-blue emissions and near-unity photoluminescence quantum yield.

View Article and Find Full Text PDF

In order to solve the problems of inefficient allocation of teaching resources and inaccurate recommendation of learning paths in higher education, this paper proposes a smart education optimization model (SEOM) by combining the improved random forest algorithm (RFA) based on adaptive enhancement mechanism and the Graph Neural Network (GNN) algorithm. The public data and information such as the national higher education intelligent education platform are collected, and SEOM is trained and verified. The results show that SEOM has high accuracy and generalization ability in three different teaching scenes: online mixed teaching, personalized teaching and project-based teaching.

View Article and Find Full Text PDF

Brain-inspired electronics with synaptic functions hold significant promise for advancing artificial intelligent applications. In this study, we demonstrate the synaptic feature of quantum-dot light-emitting diodes (QLEDs), which can convert electrical pulses into synapse-like light signals (the brightness gradually increases as the electrical pulses are prolonged). These features are analogous to learning and forgetting in biological synapses.

View Article and Find Full Text PDF

Intrinsic or acquired resistance to chemical drugs severely limits their therapeutic efficacy in cancer treatment. Various intracellular antioxidant molecules, particularly glutathione (GSH), play a crucial role in maintaining intracellular redox homeostasis by mitigating the overproduced reactive oxygen species (ROS) due to rapid cell proliferation. Notably, these antioxidants also eliminate chemical-drug-induced ROS, eventually diminishing their cytotoxicity and rendering them less effective.

View Article and Find Full Text PDF

FOLFOX regimen, composed of folinic acid, 5-fluorouracil (5-FU) and oxaliplatin (OXP), has been used as clinical standard therapeutic regimen in treatments of colorectal cancer (CRC) and esophageal squamous cell carcinoma (ESCC). To further improve its therapeutic outcomes, FOLFOX was combined with anti-PD-1 antibody to form an advanced chemo-immune combination strategy, which has been proven more efficient in controlling cancer progression and prolonging patients' survival in various clinical trials. However, bad tumor accumulation, relative high toxicity, numerous treatment cycles with high fees and low compliance as well as drug resistance seriously limit the prognosis of FOLFOX regimen.

View Article and Find Full Text PDF

The aging phenomenon is commonly observed in quantum-dot light emitting diodes (QLEDs), involving complex chemical or physical processes. Resolving the underlying mechanism of these aging issues is crucial to deliver reliable electroluminescent devices in future display applications. Here, we report a reversible positive aging phenomenon that the device brightness and efficiency significantly improve after device operation, but recover to initial states after long-time storage or mild heat treatment, which can be termed as warming-up effects.

View Article and Find Full Text PDF

The operational stability of the blue quantum dot light-emitting diode (QLED) has been one of the most important obstacles to initialize its industrialization. In this work, we demonstrate a machine learning assisted methodology to illustrate the operational stability of blue QLEDs by analyzing the measurements of over 200 samples (824 QLED devices) including current density-voltage-luminance (J-V-L), impedance spectra (IS), and operational lifetime (T95@1000 cd/m). The methodology is able to predict the operational lifetime of the QLED with a Pearson correlation coefficient of 0.

View Article and Find Full Text PDF
Article Synopsis
  • * The existing blue quantum dots achieve high efficiency but suffer from significant surface-bulk coupling, limiting their operational lifespan due to localized charges affecting performance.
  • * A novel approach using blue quantum dots with a modified core-shell structure helps reduce this coupling, allowing for a range of emission colors and improved operational lifetimes of 75 to 227 hours, surpassing previous benchmarks.
View Article and Find Full Text PDF

Blue quantum dot (QD) light emitting diode (QLED) developments are far lagging behind the red and green ones as it becomes difficult to balance charge injection and photo stability than the latter. Here, we introduced a combination of a low band energy shell with better surfactants, which largely meet both abovementioned requirements. Our simulation pinpoints that it is the exposed Se on the QD surface, which causes non-radiative relaxations.

View Article and Find Full Text PDF
Article Synopsis
  • Colloidal quantum dot (QD) emitters have potential for next-gen displays, but current manufacturing methods lack precision and uniformity for large-scale applications.
  • * Researchers introduced a selective electrophoretic deposition (SEPD) technique combined with photolithography, allowing for high-resolution, cost-effective QD patterning beyond 1,000 pixels-per-inch.
  • * This method enables precise control over QD thickness and properties, improving efficiency and demonstrating its practical use for creating full-color QD displays and QLEDs suitable for commercial production.
View Article and Find Full Text PDF

The tissue-specific targeted delivery and efficient cellular uptake of siRNAs are the main obstacles to their clinical application. Antibody-siRNA-conjugates (ARCs) can deliver siRNA by exploiting the targeting property of antibodies like antibody-drug conjugates (ADCs). However, the effective conjugation of antibodies and siRNAs and the release of siRNAs specifically at target sites have posed challenges to the development of ARCs.

View Article and Find Full Text PDF

As the development of artificial intelligence (AI) technology, the deep-learning (DL)-based Virtual Reality (VR) technology, and DL technology are applied in human-computer interaction (HCI), and their impacts on modern film and TV works production and audience psychology are analyzed. In film and TV production, audiences have a higher demand for the verisimilitude and immersion of the works, especially in film production. Based on this, a 2D image recognition system for human body motions and a 3D recognition system for human body motions based on the convolutional neural network (CNN) algorithm of DL are proposed, and an analysis framework is established.

View Article and Find Full Text PDF
Article Synopsis
  • - The inefficiency and rapid deterioration of ink-jet printed quantum dot light emitting diodes (QLEDs) limit their use in next-gen displays, mainly due to unresolved issues with trap states on the quantum dot surface.
  • - A new approach involving dual ionic passivation significantly improved the performance of ink-jet printed QLEDs, achieving an external quantum efficiency of over 16% and a lifespan exceeding 1.7 million hours.
  • - The innovative liquid phase exchange of ligands meets the needs of ink-jet printing, paving the way for mass production and broader industrial applications of QLED technology.
View Article and Find Full Text PDF

The operating lifetime of blue quantum-dot light-emitting diodes (QLED) is currently a short slab for this emerging display technology. To pinpoint the origin of device degradation, here we apply multiple techniques to monitor the electric-field distribution and space-charge accumulation across the multilayered structure before and after lifetime tests. Evident by charge-modulated electro-absorption and capacitance-voltage characteristics, the excited electrons in blue quantum dots (QD) are prone to cross the type II junction between the QD emission layer and the electron-transporting layer (ETL) due to the offset of conduction band minimum, leading to space-charge accumulation and operating-voltage rise in the ETL.

View Article and Find Full Text PDF

For the state-of-the-art quantum dot light-emitting diodes, while the ZnO nanoparticle layers can provide effective electron injections into quantum dots layers, the hole transporting materials usually cannot guarantee sufficient hole injection owing to the deep valence band of quantum dots. Developing proper hole transporting materials to match energy levels with quantum dots remains a great challenge to further improve the device efficiency and operation lifetime. Here we demonstrate high-performance quantum dot light-emitting diodes with much extended operation lifetime using quantum dots with tailored energy band structures that are favorable for hole injections.

View Article and Find Full Text PDF

A solution-processed molybdenum oxide (MoO ) as the hole injection layer (HIL) by doctor-blade coating was developed to improve the efficiency and lifetime of red-emitting quantum-dot light-emitting diodes (QD-LEDs). It has been demonstrated that by adding isopropyl alcohol into the MoO precursor during the doctor-blade coating process, the morphology, composition, and the surface electronic structure of the MoO HIL could be tailored. A high-quality MoO film with optimized charge injection was obtained, based on which all-solution-processed highly efficient red-emitting QD-LEDs were realized by using a low-cost doctor-blade coating technique under ambient conditions.

View Article and Find Full Text PDF

We report full-color quantum-dot-based light-emitting diodes (QLEDs) with high efficiency and long-lifetime by employing high quantum-yield core/shell QDs with thick shells. The increased shell thickness improves the confinement of excitons in the QD cores, and helps to suppress Auger recombination and Förster resonant energy transfer among QDs. Along with optimizing the QD emitting layer thickness and hole transport materials, we achieved significant improvements in device performance as a result of increasing the QD shell thickness to above 5 nm.

View Article and Find Full Text PDF

To improve the performance of inverted polymer solar cells based on a ternary blend of polymerthieno [3,4-b] thiophene/benzodithiophene (PTB7), [6,6]-phenyl C-butyric acid methyl ester (PCBM) and indene-C60-bisadduct (ICBA), a two-layer structure of zinc oxide (ZnO) and Al-doped zinc oxide (AZO) nanoperticles is used to improve electron extraction. Comparing to ZnO, AZO has lower work function and thus provides larger built-in potential across the organic heterojunction, resulting in more efficient photo-current extraction and larger open circuit voltages. Optimum devices with ZnO/AZO nanoparticles show enhancement of both short circuit current and open circuit voltage, leading to a power conversion efficiency (PCE) of 8.

View Article and Find Full Text PDF

Colloidal nanoplatelets (NPLs) have recently been introduced as semiconductor emissive materials for the fabrication of quantum dot light-emitting diodes (QLED) on account of their ultra-narrow photoluminescence (PL) linewidth. In this paper, we report a multilayer all solution-processed green QLED based on colloidal CdSe/CdS core/shell NPLs with a narrow PL full-width-at-half-maximum (FWHM) of 12 nm. Our characterization results reveal that this kind of NPL containing QLED exhibit a low operating voltage of 2.

View Article and Find Full Text PDF

A highly efficient inverted polymer solar cell (PSC) has been successfully demonstrated by using a ZnO nanoparticle (NP) and poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) bilayer structure as an effective electron collecting layer. This ZnO/PFN bilayer structure is designed to combine the advantages of both ZnO and PFN, based on the performance comparison of ZnO-only, PFN-only, and ZnO/PFN bilayer devices in our work. ZnO NPs can serve as an efficient electron transport and buffer layer for reduced series resistance, while the PFN interlayer can improve the energy level alignment of devices through the formation of an interfacial dipole.

View Article and Find Full Text PDF

We report high-efficiency blue-violet quantum-dot-based light-emitting diodes (QD-LEDs) by using high quantum yield ZnCdS/ZnS graded core-shell QDs with proper surface ligands. Replacing the oleic acid ligands on the as-synthesized QDs with shorter 1-octanethiol ligands is found to cause a 2-fold increase in the electron mobility within the QD film. Such a ligand exchange also results in an even greater increase in hole injection into the QD layer, thus improving the overall charge balance in the LEDs and yielding a 70% increase in quantum efficiency.

View Article and Find Full Text PDF

We report the development of efficient small molecular organic photovoltaic devices incorporating tetracene anode interfacial layers. Planar heterojunction devices employing the tetracene anode interfacial layer achieved an EQE enhancement of 150% in the spectral region corresponding to ZnPc absorption. We demonstrate that this enhancement is due to the combined effect of the tetracene layer providing exciton-blocking at the anode/donor interface and potentially an increase in the exciton diffusion length in the ZnPc layer due to increased crystallinity and more preferred molecular stacking orientation.

View Article and Find Full Text PDF

Advances in colloidal inorganic nanocrystal synthesis and processing have led to the demonstration of organic-inorganic hybrid photovoltaic (PV) cells using low-cost solution processes from blends of conjugated polymer and colloidal nanocrystals. However, the performance of such hybrid PV cells has been limited due to the lack of control at the complex interfaces between the organic and inorganic hybrid active materials. Here we show that the efficiency of hybrid PV devices can be significantly enhanced by engineering the polymer-nanocrystal interface with proper chemical treatment.

View Article and Find Full Text PDF

A series of chemically bonded Bismuth oxyiodide (BiOI)-graphene (GR) nanocomposites have been synthesized by a facile one-step hydrothermal method. Both the reduction in graphene oxide (GO) and the formation of BiOI nanocrystals were achieved simultaneously during the hydrothermal reaction. The prepared materials were characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectra, high-resolution transmission electron micrographs (HRTEM), UV-vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy.

View Article and Find Full Text PDF

The light extraction efficiency in organic light-emitting devices (OLEDs) is enhanced by up to 2.6 times when a close-packed, hemispherical transparent polymer microlens array (MLA) is molded on the light-emitting surface of a top-emitting device. The microlens array helps to extract the waveguided optical emission in the organic layers and the transparent top electrode, and can be manufactured in large area with low cost.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session610m76kaclkqj1r36su2aid8t7im4m0l): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once