RESUMEN
Light-emitting diodes (LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiencies (EQEs) of more than 25% with narrowband emission1,2, but these LEDs have limited operating lifetimes. We posit that poor long-range ordering in perovskite QD films-variations in dot size, surface ligand density and dot-to-dot stacking-inhibits carrier injection, resulting in inferior operating stability because of the large bias required to produce emission in these LEDs. Here we report a chemical treatment to improve the long-range order of perovskite QD films: the diffraction intensity from the repeating QD units increases three-fold compared with that of controls. We achieve this using a synergistic dual-ligand approach: an iodide-rich agent (aniline hydroiodide) for anion exchange and a chemically reactive agent (bromotrimethylsilane) that produces a strong acid that in situ dissolves smaller QDs to regulate size and more effectively removes less conductive ligands to enable compact, uniform and defect-free films. These films exhibit high conductivity (4 × 10-4 S m-1), which is 2.5-fold higher than that of the control, and represents the highest conductivity recorded so far among perovskite QDs. The high conductivity ensures efficient charge transportation, enabling red perovskite QD-LEDs that generate a luminance of 1,000 cd m-2 at a record-low voltage of 2.8 V. The EQE at this luminance is more than 20%. Furthermore, the stability of the operating device is 100 times better than previous red perovskite LEDs at EQEs of more than 20%.
RESUMEN
Alloying lanthanide ions (Yb3+) into perovskite quantum dots (Yb3+:CsPb(Cl1-xBrx)3) is an effective method to achieve efficient near-infrared (NIR) luminescence (>950 nm). Increasing the Yb3+ alloying ratio in the perovskite matrix enhances the luminescence intensity of Yb3+ emission at 990 nm. However, high Yb3+ alloying (>15%) results in vacancy-induced inferior material stability. In this work, we developed a polarity-mediated antisolvent manipulation strategy to resolve the incompatibility between a high Yb3+ alloying ratio and inferior stability of Yb3+:CsPb(Cl1-xBrx)3. Precise control of solution polarity enables increased uniformity of the perovskite matrix with fewer trap densities. Employing this strategy, we obtain Yb3+:CsPb(Cl1-xBrx)3 with the highest Yb3+ alloying ratio of 30.2% and a 2-fold higher electroluminescence intensity at 990 nm. We lever the engineered Yb3+:CsPb(Cl1-xBrx)3 to fabricate NIR-LEDs, achieving a peak external quantum efficiency (EQE) of 8.5% at 990 nm: this represents the highest among perovskite NIR-LEDs with an emission wavelength above 950 nm.
RESUMEN
We conducted this study aimed to explore the effect of operating room nursing intervention on wound infection in patients undergoing ovarian cysts surgery. A computer system was used to search PubMed, Web of Science, EMBASE, Cochrane Library, Wanfang, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure databases, from database inception to October 2023, for randomised controlled trials (RCTs) on the application of operating room nursing intervention to ovarian cyst surgery. Literature that met the requirements was independently screened by two researchers, and data were extracted and assessed for literature quality. RevMan 5.4 software was applied for data analysis. Fifteen RCTs involving 1187 patients were finally included. The analyses revealed that, compared with routine nursing, the implementation of operating room nursing intervention had a significant advantage in reducing the incidence of wound infections (1.17% vs. 5.44%, odds ratio [OR]: 0.30, 95% confidence interval [CI]: 0.15-0.58, p = 0.0004) and postoperative complications (6.34% vs. 25.17%, OR: 0.20, 95%CI: 0.13-0.29, p < 0.00001), as well as being able to shorten the operative time (standardised mean difference [SMD]: -3.93, 95%CI: -5.67 to -2.20, p < 0.00001), hospital length of stay (SMD: -2.54, 95%CI: -3.19 to -1.89, p < 0.00001) and gastrointestinal recovery time (SMD: -1.61, 95%CI: -2.24 to -0.98, p < 0.00001) in patients undergoing ovarian cysts surgery. This study confirmed by meta-analysis that the operating room nursing intervention can significantly reduce the incidence of wound infection and complications, shorten the operative time, gastrointestinal recovery time, and hospital length of stay after ovarian cyst surgery.