Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract

Research on Properties of X-Ray Detection Film Based on Thallium Doped Cesium Iodide

As X-ray detection imaging has a wide range of applications in medicine, industry, public safety, etc., it is of great significance to study its imaging mechanism and improve its imaging performance. Based on the process of X-ray luminescence in the scintillator material, this paper established a simulation model using a microcrystalline column structure to investigate the relationship between the thickness of the detection film and the light conversion efficiency. With the help of the simulation tool MATLAB, the Monte Carlo method was used to simulate the light conversion process of X-ray in the film, and the results were obtained as follows. Under the condition of other parameters unchanged, the luminous efficiency reached the peak value with the increase of the film thickness, and then gradually decreased with the increase of film thickness. The reason why the conversion efficiency in the early stage increases with the increase of the film thickness is that the film is in a saturated state, and increasing the thickness can cause more X-ray particles to be converted. As the film thickness increases, more fluorescent photons are absorbed as they propagate in the film, resulting in a gradual decrease in conversion efficiency. Therefore, an appropriate film thickness can be selected based on the simulation results to obtain the ideal light conversion efficiency.

The effect of nanoparticulate PdO co-catalysts on the faradaic and light conversion efficiency of WO3 photoanodes for water oxidation

PdO nanoparticles grown on the surface of nanostructured WO3 photoanodes dramatically increase the faradaic efficiency of water oxidation from 52% to 92%, whilst also enhancing photocurrent generation and electron extraction rates.

Enhancing near‐infrared photocatalytic activity and upconversion luminescence of BiOCl: Yb3+-Er3+ nanosheets with polypyrrole in-situ modification

Photocatalytic behavior and upconversion (UC) luminescence of rare earth ion (RE) are two opposite photophysical process, but improving the ultimate light conversion efficiency, light absorption enhancement and suppression of excited...

Improving Light Use Efficiency in C4 Plants by Increasing Electron Transport Rate

C4 plants play a key role in world agriculture and strategies to manipulate and enhance C4 photosynthesis have the potential for major agricultural impacts. The C4 photosynthetic pathway is a biochemical CO2 concentrating mechanism that requires the coordinated functioning of mesophyll and bundle sheath cells of leaves. Chloroplast electron transport in C4 plants is shared between the two cell types; it provides resources for CO2 fixation therefore underpinning the efficiency of photosynthesis. Using the model monocot C4 species Setaria viridis (green foxtail millet) we demonstrated that the Cytochrome (Cyt) b6f complex regulates the electron transport capacity and thus the rate of CO2 assimilation at high light and saturating CO2. Overexpression of the Cyt b6f in both mesophyll and bundle sheath cells results in a higher electron throughput and allows better light conversion efficiency in both photosystems. Importantly, increased Cyt b6f abundance in leaves provides higher rates of C4 photosynthesis without marked changes in Rubisco or chlorophyll content. Our results demonstrate that increasing the rate of electron transport is a viable strategy for improving the light conversion efficiency in C4 crop species like maize and sorghum.

Modulation of the photoelectrochemical behavior of Au nanocluster–TiO2 electrode by doping

Optoelectronic properties of Au18(SR)14 are modulated by Ag doping, and its influence on photoelectrochemical performance is investigated. The best compromise for light conversion efficiency is made when a single Ag atom is incorporated.

Behaviour of Y203:Eu3+ Scintillator under Radiation used in Medical Applications

The Y2 O3:Eu3+ scintillator was studied for use in radiation detectors of medical imaging systems. Y2 O3 :Eu3+ was used in the form of laboratory prepared test screens. The x-ray luminescence efficiency of the screens was measured for tube voltages up 250 kVp. The intrinsic x-ray to light conversion efficiency (nc) and other optical parameters of the Y2 03:Eu3+ scintillator related to optical scattering, absorption, and reflection were determined. The light emission spectrum of Y2 03:Eu3+ was measured (λ=613 rim). The x-ray luminescence efficiency peaked at 180 mg/cm2 screen coating weight. The intrinsic x-ray to light conversion efficiency was found to be nc =0.095. Results indicated that Y2 03:Eu3+ is a medium to high overall performance material that could be used in medical imaging systems.