Robust, Narrow-Band Nanorods LEDs with Luminous Efficacy > 200 lm/W: Next-Generation of Efficient Solid-State Lighting.

Energy-efficient white light-emitting diodes (LEDs) are in high demand across the society. Despite the significant advancements in the modern lighting industry based on solid-state electronics and inorganic phosphor, solid-state lighting (SSL) continues to pursue improved efficiency, saturated color performance, and longer lifetime. Here in this article, robust, narrow emission band nanorods (NRs) are disclosed with tailored wavelengths, aiming to enhance the color rendering index (CRI) and luminous efficacy (LE). The fabricated lighting device consists of NRs of configuration CdSe/ZnxCd1-xS/ZnS, which can independently tune CRI R1-R9 values and maximize the luminous efficacy. For general lighting, NRs with quantum yield (QY) up to 96% and 99% are developed, resulting in ultra-efficient LEDs reaching a record high luminous efficacy of 214 lm W-1 (certified by the National Accreditation Service). Furthermore, NRs are deployed onto mid-power (0.3 W@ 50 mA) LEDs, showing significantly enhanced long-term stability (T95 = 400 h @ 50 mA). With these astonishing properties, the proposed NRs can pave the way for efficient lighting with desired optical spectrum.

Ultralow Roll-Off Quantum Dot Light-Emitting Diodes Using Engineered Carrier Injection Layer.

Quantum dot (QD) light-emitting diodes (QLEDs) have attracted extensive attention due to their high color purity, solution-processability, and high brightness. Due to extensive efforts, the external quantum efficiency (EQE) of QLEDs has approached the theoretical limit. However, because of the efficiency roll-off, the high EQE can only be achieved at relatively low luminance, hindering their application in high-brightness devices such as near-to-eye displays and lighting applications. Here, this article reports an ultralow roll-off QLED that is achieved by simultaneously blocking electron leakage and enhancing the hole injection, thereby shifting the recombination zone back to the emitting QDs layer. These devices maintain EQE over 20.6% up to 1000 mA cm-2 current density, dropping only by ≈5% from the peak EQE of 21.6%, which is the highest value ever reported for the bottom-emitting red QLEDs. Furthermore, the maximum luminance of the optimal device reaches 320 000 cd m-2 , 2.7 times higher than the control device (Lmax : 128 000 cd m-2 ). A passive matrix (PM) QLED display panel with high brightness based on the optimized device structure is also demonstrated. The proposed approach advances the potential of QLEDs to operate efficiently in high-brightness scenarios.

Dual-energy spectral detector computed tomography differential diagnosis of adrenal adenoma and pheochromocytoma: Changes in the energy level curve, a phenomenon caused by lipid components?

Background and objectives: Pheochromocytoma and adrenal adenoma are common space-occupying lesions of the adrenal gland, and incorrect surgery may lead to adrenal crisis. We used a new method, dual-energy spectral detector computed tomography (SDCT), to differentiate between the two. Materials and methods: We analysed the imaging images of patients with SDCT scans and pathologically confirmed adrenal adenomas (n=70) and pheochromocytomas (n=15). The 40, 70, and 100 KeV virtual monoenergetic images (VMIs) were reconstructed based on the SCDT arterial phase, and the correlation between the arterial/venous phase iodine concentration (AP-IC/VP-IC), the effective atomic number (Z-effect), the slope of the Hounsfield unit attenuation plot (VMI slope) and the pathological results was tested. The Shapiro-Wilk test was used to determine whether the above data conformed to a normal distribution. For parameters with P greater than 0.05, Student's t test was used, and the Mann-Whitney test was used for the remaining parameters. A ROC curve was drawn based on the results. Results: Student's t test showed that the 40 KeV VMI and the VMI slope were both statistically significant (P<0.01). The Mann-Whitney U test showed that ID-A was statistically significant (P=0.004). ROC curve analysis showed that 40 keV VMI (AUC=0.818), AP-IC (AUC=0.736), difference (AUC=0.817) and VMI-Slope (0.817) could be used to differentiate adrenal adenoma from pheochromocytoma. Conclusion: The effect of lipid components on SDCT parameters can be used to differentiate adrenal adenoma from pheochromocytoma.

Improved photoelectric performance of all-inorganic perovskite through different additives for green light-emitting diodes.

The exceptional optical and electronic properties of all-inorganic cesium lead bromide (CsPbBr3) perovskite make it an ideal new optoelectronic material, but low surface coverage limits its performance. The morphological characteristics of thin films have a great influence on the performance of perovskite light emitting diodes, especially at low coverage, and an inhomogeneous surface will lead to current leakage. To tackle this problem, the widespread adoption of composite layers including polymers poly(ethylene oxide) (PEO) and organic insulating poly(vinylpyrrolidone) (PVP) and all-inorganic perovskites is an effective way to increase the surface coverage and uniformity of perovskite films and improve the performance of perovskite light emitting devices. In our work, the perovskite thin films are investigated by using PEO and PVP dual additives, and the optimized CsPbBr3-PEO-PVP LED with maximum luminance, current efficiency, and external quantum efficiency of 2353 cd m-2 (at 7.2 V), 2.14 cd A-1 (at 6.5 V) and 0.85% (at 6.5 V) was obtained. This work indicates that the method of using additives is not only the key to enhancing the quality of perovskite thin film, but also the key to achieving a higher performance perovskite LED.