Phosphine Oxide-Nd3+ Coordination Chains with Cumulated Output Enable Efficient LED-Pumping Optical Amplification.

Near-infrared luminescent rare-earth organic complexes have attracted intensive attention in the field of optical waveguide amplification. However, their optical gains were commonly less than 4 dB/cm due to limited doping concentrations. Herein, two one-dimensional (1D) Nd3+ coordination chains, namely, [Nd(TTA)3(DBTDPO)]n (Nd1) and [Nd(TTA)3(DPEPO)]n (Nd2), bridged by phosphine oxide ligands were developed for the neodymium-doped waveguide amplifier. Despite its P-P distance being similar to DBTDPO, the different P═O orientation of DPEPO renders markedly shorter intra- and interchain Nd-Nd distances for Nd2 in comparison to Nd1. Furthermore, the weaker intermolecular interactions alleviate the quenching effect for Nd2. Therefore, Nd2 can provide more locally concentrated and radiative Nd3+ ions, leading to a larger Nd3+-characteristic 1.06 µm emission intensity and duration than Nd1. Based on embedded and evanescent-field waveguide structures, Nd2 achieves state-of-the-art gain maxima of 5.7 and 4.9 dB/cm as well as outstanding gain stability. These results indicate that controllable coordination assembly of lanthanide ions in multidimension provides a flexible approach to combine local high-density outputs and effective suppression of quenching.

Interaction between hypertension and frailty and their impact on death risk in older adults: a follow-up study.

BACKGROUND: Hypertension and frailty often occur concurrently, exhibiting increasing prevalence in the older population. In this study, we analyzed the frailty status among older adults with hypertension and the impact of their interaction on death risk. METHOD: This prospective cohort survey study included data from older people in an urban community in Beijing collected between 2009 and 2020 using the cluster random sampling method. The participants were older adults who were ≥ 60 years old at the time of investigation and had lived at the place of investigation for > 1 year. The survey variables comprised those related to health and frailty status assessed during the 2009 baseline survey, along with death-related information as outcome variables in 2020. Additionally, a frailty index (FI) model was used to examine the frailty status among the older adults at baseline. The effects of hypertension prevalence on the age-related frailty changes as well as on mortality for varying degrees of frailty were further analyzed. Lastly, Cox regression and Kaplan-Meier curves were applied to evaluate the impact of the interaction between hypertension and frailty on death risk. RESULTS: Ultimately, 1197 older individuals aged between 60 and 101 years(average age at baseline: 74.8 ± 8.6 years) were included .Among them, 475 individuals were men (mean age:74.8 ± 8.8 years), and 722 were women (mean age:74.8 ± 8.4 years).Frailty was identified in 151 individuals, leading to a prevalence rate of 12.6%(151/1197),while hypertension was detected in 593 (prevalence rate:49.5% [593/1197]).A total of 443 deaths were recorded by 2020, resulting in a mortality rate of 37.0% (443/1197).Moreover, FI values and mortality rates were higher at any age in older adults with hypertension compared with those without hypertension. Survival time analysis showed that the median survival time of older adults with hypertension and frailty was the shortest (39.0[95%CI: 35.6-42.3] months)when compared with that of older adults without hypertension but with frailty (52.9 [95%CI: 46.6-59.3] months), those with hypertension but without frailty (102.7 [95%CI: 98.7-106.8] months), and those without hypertension and frailty (127.9 [95%CI: 113.5-134.7] months),with log-rank x2 = 999.686 and P < 0.001. Furthermore, Cox regression results demonstrated that older adults with hypertension and frailty had the highest death risk when compared with that of older adults without hypertension and frailty (HR = 1.792, P < 0.001), those without hypertension but with frailty (HR = 1.484, P < 0.001), and those with hypertension but without frailty (HR = 1.406, P = 0.005). CONCLUSION: Frailty is prevalent among older adults with hypertension; however, older adults with both hypertension and frailty have a relatively higher mortality risk. Therefore, screening and assessment of frailty in the older population with hypertension are crucial for its early identification, thereby enabling timely and appropriate interventions to prevent or delay the adverse effects of this concurrent condition.

Ligand-mediate exciton allocation enables efficient cluster-based white light-emitting diodes via single and heavy doping.

Despite potential in high-resolution and low-cost displays and lighting, multi-doping structures and low concentrations (<1%) limit repeatability and stability of single-emissive-layer white light-emitting devices. Herein, we report a singly doped white-emitting system of blue thermally activated delayed fluorescence host matrix (CzAcSF) doped by yellow Cu4I4 cluster ([tBCzDppy]2Cu4I4). CzAcSF:x% [tBCzDppy]2Cu4I4 films realize photo- and electro-luminescence colors from cool white to warm white at x = 20-40. The external quantum efficiency of 23.5% was achieved at x = 30, indicating the record-high efficiency among solution-processed analogs and the largest doping concentration among efficient white light-emitting devices. It shows that di(tert-butyl)carbazole moieties in [tBCzDppy]2Cu4I4 provide high-lying excited energy levels at~2.6 eV to mediate energy transfer from CzAcSF (2.9 eV) to coordinated Cu4I4 (2.2 eV). Our results demonstrate the antenna effect of ligands on optimizing charge and energy transfer in organic-cluster systems and superiority of white cluster light-emitting diodes in practical applications.

Delayed room temperature phosphorescence enabled by phosphines.

Organic ultralong room-temperature phosphorescence (RTP) usually emerges instantly and immediately decays after excitation removal. Here we report a new delayed RTP that is postponed by dozens of milliseconds after excitation removal and decays in two steps including an initial increase in intensity followed by subsequent decrease in intensity. The delayed RTP is achieved through introduction of phosphines into carbazole emitters. In contrast to the rapid energy transfer from single-molecular triplet states (T1) to stabilized triplet states (Tn*) of instant RTP systems, phosphine groups insert their intermediate states (TM) between carbazole-originated T1 and Tn* of carbazole-phosphine hybrids. In addition to markedly increasing emission lifetimes by ten folds, since TM → Tn* transition require >30 milliseconds, RTP is thereby postponed by dozens of milliseconds. The emission character of carbazole-phosphine hybrids can be used to reveal information through combining instant and delayed RTP, realizing multi-level time resolution for advanced information, biological and optoelectronic applications.

Allochroic cluster light-emitting diodes based on unique µ3-tetraphosphine Cu3X3 crowns with tunable excited states.

Multicomponent excited states endow copper iodide clusters with allochroic properties under diverse stimuli. However, crystal states are required, and cluster stimulus sensitivity hampers electroluminochromism. We developed PhQPCu3X3 (X = Cl, Br, and I) with the first µ3-bridging tetraphosphine ligand, whose Cu3X3 crowns were exposed to external stimulus. The increased proportion of Cu3X3 results in equal contributions of cluster- and ligand-centered components to excited states, the former of which is highly sensitive to grind, vapor, and, especially, electric stimuli, due to semi-exposed Cu3X3. Through vacuum evaporation and vapor fumigation of cluster-based emissive layers, the diodes' electroluminescence colors changed from yellow to white. Joule heat during device operation induced further color variation to orange, corresponding to Commission Internationale de l'Eclairage coordinates of PhQPCu3I3 changed from (0.44 ± 0.1, 0.34 ± 0.1) to (0.57 ± 0.1, 0.42 ± 0.1). These results demonstrate the superiority of luminescent clusters in accurate excited-state modulation, holding promise for wide applications.