Chemical Bath Deposited Antimony Oxide Thin Films for Efficient Perovskite Solar Cells.

The metal oxide electron transport layers (ETLs) of n-i-p perovskite solar cells (PSCs) are dominated by TiO2 and SnO2, while the efficacy of the other metal oxide ETLs still lags far behind. Herein, an emerging, economical, and environmentally friendly metal oxide, antimony oxide (Sb2Ox, x = 2.17), prepared by chemical bath deposition is reported as an alternative ETL for PSCs. The deposited Sb2Ox film is amorphous and very thin (∼10 nm) but conformal on rough fluorine-doped tin oxide substrates, showing matched energy levels, efficient electron extraction, and then reduced nonradiative recombination in PSCs. The champion PSC based on the Sb2Ox ETL delivers an impressive power conversion efficiency of 24.7% under one sun illumination, which represents the state-of-the-art performance of all metal oxide ETL-based PSCs. Additionally, the Sb2Ox-based devices show improved operational and thermal stability compared to their SnO2-based counterparts. Armed with these findings, we believe this work offers an optional ETL for perovskites-based optoelectronic devices.

NLRP3 expression and its predictive role in preserved ejection fraction among non-valvular atrial fibrillation patients.

INTRODUCTION: To investigate the expression and predictive value of NOD-like receptor thermoprotein domain-related protein 3 (NLRP3) in patients with nonvalvular atrial fibrillation (NVAF) with ejection fraction preserved heart failure (HFpEF). METHODS: A retrospective analysis of 121 patients diagnosed with NVAF. According to the occurrence of HFpEF, 81 patients was assigned in the NVAF group and 40 patients in the NVAF/HFpEF group. The levels of NLRP3, B natriuretic peptide (BNP), and interleukin-1ß were determined using enzyme-linked immunosorbent assay (ELISA). Independent predictors for HFpEF in NVAF was determined using logistic regression. The receiver operating characteristic curve (ROC) was used to evaluate the predictive value of each factor. RESULTS: Expression levels of NLRP3, BNP, and IL-1ß in the NVAF/HFpEF group, as well as the H2FPEF score was significantly higher than those in the NVAF group. Pearson analysis showed that NLRP3, BNP, and IL-1ß expression levels in NVAF patients and H2FPEF score was positively correlated (r=0.409, r=0.244, r=0.299, p < 0.001). Multivariate logistic regression analysis showed that NLRP3, BNP, or H2FPEF score can be used as independent factor for predicting the occurrence of HFpEF in NVAF. ROC curves showed that the area under the curve (AUC) of NLRP3, BNP, and H2FPEF score for predicting the occurrence of HFpEF in NVAF patients were 0.856, 0.831 and 0.811, respectively. CONCLUSION: NLRP3 level is elevated in the peripheral blood of NVAF patients with HFpEF and is positively correlated with the H2FPEF score. NLRP3 may serve as a potential predictor of HFpEF in patients with NVAF.

Xanthones with multiple roles against diabetes: their synthesis, structure-activity relationship, and mechanism studies.

A four-step synthetic process has been developed to prepare 1,3,5,8-tetrahydroxyxanthone (2a) and its isomer 1,3,7,8-tetrahydroxyxanthone (2b). 25 more xanthones were also synthesized by a modified scheme. Xanthone 2a was identified as the most active inhibitor against both α-glucosidase and aldose reductase (ALR2), with IC50 values of 7.8 ± 0.5 µM and 63.2 ± 0.6 nM, respectively, which was far active than acarbose (35.0 ± 0.1 µM), and a little more active than epalrestat (67.0 ± 3.0 nM). 2a was also confirmed as the most active antioxidant in vitro with EC50 value of 8.9 ± 0.1 µM. Any structural modification including methylation, deletion, and position change of hydroxyl group in 2a will cause an activity loss in inhibitory and antioxidation. By applying a H2 O2 -induced oxidative stress nematode model, it was confirmed that xanthone 2a can be absorbed by Caenorhabditis elegans and is bioavailable to attenuate in vivo oxidative stress, including the effects on lifespan, superoxide dismutase, Catalase, and malondialdehyde. 2a was verified with in vivo hypoglycemic effect and mitigation of embryo malformations in high glucose. All our data support that xanthone 2a behaves triple roles and is a potential agent to treat diabetic mellitus, gestational diabetes mellitus, and diabetic complications.

High-Throughput Deposition of Recyclable SnO2 Electrodes toward Efficient Perovskite Solar Cells.

Chemical bath deposited (CBD) SnO2 is one of the most prevailing electron transport layers for realizing high-efficiency perovskite solar cells (PSCs) so far. However, the state-of-the-art CBD SnO2 process is time-consuming, contradictory to its prospect in industrialization. Herein, a simplified yet efficient method is developed for the fast deposition of SnO2 electrodes by incorporating a concentrated Sn source stabilized by the ethanol ligand with antimony (Sb) doping. The higher concentration of Sn source promotes the deposition rate, and Sb doping improves the hole-blocking capability of the CBD SnO2 layer so that its target thickness can be reduced to further save the deposition time. As a result, the deposition time can be appreciably reduced from 3-4 h to only 5 min while maintaining 95% of the maximum efficiency, indicating the power of the method toward high-throughput production of efficient PSCs. Additionally, the CBD SnO2 substrates are recyclable after removing the upper layers of complete PSCs, and the refurbished PSCs can maintain ≈98% of their initial efficiency after three recycling-and-fabrication processes.

In situgeneration of FeOOH/NiOOH interface in FeS2/NiS2nanosheets through deep reconstruction for efficient oxygen evolution reaction.

Transition metal sulfides (TMSs) for electrochemical water splitting undergo significant self-reconstruction to form actual active species favorable for high oxygen evolution reaction (OER) performance. However, the complete self-reconstruction of most reported TMSs in alkaline media is unfrequent and the active species cannot be efficiently used. Herein, self-supported FeS2/NiS2nanosheet arrays (FeNiS) are deliberately fabricated as pre-catalysts and then accomplished deep phase transformation into low-crystalline and ultrathin FeOOH/NiOOH (FeNiS-R) nanosheets favorable to alkaline OER. Variousex situcharacterization studies uncover that the FeNiS-R with abundant interfaces is generated via complete reconstruction during electrolysis and the high-valence Fe and Ni in the FeNiS-R interface are the real active sites for high OER activity. The reconstructed FeNiS-R exhibits a small overpotential of 290 mV at 100 mA cm-2and favorable durability (≥80 h), much superior to commercial benchmark IrO2. This work provides a promising avenue to achieve the deep reconstruction of TMSs and the targeted design of OER catalysts in energy devices.

Length and rigidity of the spacer impact on aldose reductase inhibition of the 5F-like ARIs in a dual-occupied mode.

The primary objective of this study was to investigate the structure-activity relationship of a new series of 5F-like Aldose Reductase Inhibitors (ARIs) using in silico docking method. In this perspective, 6 novel ARIs have been designed and synthesized. Evaluation of the inhibition of these compounds to ALR2 was carried on with epalrestat and 5F as the references. It was found that the spacer of 5F-like ARIs has a great influence on their inhibitory activity. Rigid spacer with length equal to 3 âˆ¼ 4 carbon alkyl chain brings about better inhibitory activity. Among them, compound 4b was verified as the most active ARIs, where its IC50 value was 16.8 ± 1.3 nM. Furthermore, in silico docking studies using AutoDock 4.2 as well as molecular simulation using GROMACS 2022.1 showed that 5F-like ARIs adopt a dual-occupation mode. The interaction energy (-25 to -74 kcal/mol), as well as MM-GBSA binding free energy (-37 to -65 kcal/mol) was positively correlated with their ALR2 inhibition constant (2000 to 16.8 nM). Docking interaction explained well the structure-activity relationship. A pharmacophore model has been set up for 5F-like ARIs thereafter. This model indicates that as an effective ARI, the entity should have four characteristics: an aromatic center, two hydrogen bond donors, and one hydrogen bond acceptor. By the way, all the 5F-like ARIs reported here are good to mild antioxidant with EC50 value between 13.6 ± 1.2 and 71.1 ± 3.2 µM. All our data direct the further development of more optimal ARIs for the treatment of diabetic complication in the future.

The accelerated aging skin in rhino-like SHJHhr mice.

SHJHhr mice line is rhino-like mice with a nonsense Hairless (Hr) mutant, which shows the characteristic of shedding hair and wrinkled skin with increasing age. Through histological analysis and aging indexes detection, SHJHhr mice show an increased thickness skin with degraded hair follicle and dermal cysts and disorganized collagen fibres, as well as decreased level of Hyp. Meanwhile, the aging markers p16 and p21 are significantly higher in SHJHhr mouse skin than ICR mouse skin at same age. Moreover, the data of MDA and SOD show a higher oxidative stress in SHJHhr mouse skin, and the levels of Nrf2 and its targets are significantly downregulated, which suggests SHJHhr mice have a faster aging skin and its reason maybe poor antioxidative protection. Overall, this study shows SHJHhr mice with an accelerated aging skin, which suggests the role of Hr gene in skin aging.

Diagnostic accuracy of dual-energy computed tomography to differentiate intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke: systematic review and meta-analysis.

OBJECTIVES: To assess whether dual-energy computed tomography (DECT), using conventional computed tomography or magnetic resonance imaging as a reference standard, is sufficiently accurate to differentiate intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. METHODS: On January 20, 2021, we searched the PubMed Medline, Embase, Web of Science, and Cochrane Library databases. QUADAS-2 was used to assess the risk of bias and applicability. Meta-analyses were performed using a bivariate random-effects model. To explore sources of heterogeneity, meta-regression analyses were performed. Deeks' funnel plot asymmetry test was used to assess publication bias. RESULTS: A total of 7 studies (269 patients, 269 focal areas) were included. The pooled mean sensitivity, specificity, and accuracy of DECT in identifying intracerebral hemorrhage from contrast extravasation after mechanical thrombectomy for acute ischemic stroke were 0.77 (95% confidence interval (CI) 0.29 to 0.96), 1 (95% CI 0.86 to 1), and 0.99 (95% CI 0.98 to 1), respectively. This evidence was of moderate certainty due to the risk of bias. Higgin's I-squared for study heterogeneity was observed for the pooled sensitivity (I2 = 78.88%) and pooled specificity (I2 = 82.12%). Moreover, Deeks' funnel plot asymmetry test revealed no publication bias (p = 0.38). CONCLUSION: DECT shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. Nevertheless, there was substantial and moderate heterogeneity among the studies. Future large-scale, prospective cohort studies are warranted to validate our findings. KEY POINTS: • Dual-energy computed tomography shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. • Via meta-regression analysis, we found various possible covariates, including the publication date, image analysis, index test time, time of follow-up imaging, and reference standard judgment, that had an important effect on the heterogeneity. • There were no concerns regarding applicability in any of the included studies.

Functional Connectivity Changes in Multiple-Frequency Bands in Acute Basal Ganglia Ischemic Stroke Patients: A Machine Learning Approach.

Purpose: Several functional magnetic resonance imaging (fMRI) studies have investigated the resting-state functional connectivity (rs-FC) changes in the primary motor cortex (M1) in patients with acute basal ganglia ischemic stroke (BGIS). However, the frequency-specific FC changes of M1 in acute BGIS patients are still unclear. Our study was aimed at exploring the altered FC of M1 in three frequency bands and the potential features as biomarkers for the identification by using a support vector machine (SVM). Methods: We included 28 acute BGIS patients and 42 healthy controls (HCs). Seed-based FC of two regions of interest (ROI, bilateral M1s) were calculated in conventional, slow-5, and slow-4 frequency bands. The abnormal voxel-wise FC values were defined as the features for SVM in different frequency bands. Results: In the ipsilesional M1, the acute BGIS patients exhibited decreased FC with the right lingual gyrus in the conventional and slow-4 frequency band. Besides, the acute BGIS patients showed increased FC with the right medial superior frontal gyrus (SFGmed) in the conventional and slow-5 frequency band and decreased FC with the left lingual gyrus in the slow-5 frequency band. In the contralesional M1, the BGIS patients showed lower FC with the right SFGmed in the conventional frequency band. The higher FC values with the right lingual gyrus and left SFGmed were detected in the slow-4 frequency band. In the slow-5 frequency band, the BGIS patients showed decreased FC with the left calcarine sulcus. SVM results showed that the combined features (slow-4+slow-5) had the highest accuracy in classification prediction of acute BGIS patients, with an area under curve (AUC) of 0.86. Conclusion: Acute BGIS patients had frequency-specific alterations in FC; SVM is a promising method for exploring these frequency-dependent FC alterations. The abnormal brain regions might be potential targets for future researchers in the rehabilitation and treatment of stroke patients.

Air-Processed MAPbBr3 Perovskite Thin Film with Ultrastability and Enhanced Amplified Spontaneous Emission.

The poor stability, in particular with respect to temperature, moisture, and light exposure, remains a ubiquitous impediment virtually for metal halide perovskite materials and devices in their future practical application. Herein, from the perspective of precursor solution chemistry, ionic liquid solvent methylammonium acetate (MAAc) is introduced to prepare high-quality MAPbBr3 perovskite thin films in a one-step air-processing process without anti-solvent treatment. Due to formation of pinhole-free, uniform, and compact MAPbBr3 perovskite film, excellent amplified spontaneous emission (ASE) with high emission efficiency and low threshold is obtained under nanosecond laser. Furthermore, the prepared MAPbBr3 perovskite exhibits excellent two-photon induced ASE with a low threshold of 100 µJ cm-2 under 800 nm femtosecond laser excitation. More importantly, in comparison with the traditional MAPbBr3 films prepared with N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), the MAPbBr3 film prepared with MAAc shows excellent optical stability: no signs of degradation under more than 2 h pulsed laser excitation, stable ASE emission spectra under the humidity of 95% and ASE spectra can be stimulated when films are kept in air for more than 6000 h without encapsulation.

Identification of recombination in novel goose parvovirus isolated from domesticated Jing-Xi partridge ducks in South China.

Outbreaks of short beak and dwarfism syndrome (SBDS), caused by a novel goose parvovirus (NGPV), have occurred in China since 2015. This rapidly spreading, infectious disease affects ducks in particular, with a high morbidity and low mortality rate, causing huge economic losses. This study analyzed the evolution of NGPV isolated from Jing-Xi partridge duck with SBDS in South China. Complete genome sequences of the NGPV strains GDQY1802 and GDSG1901 were homologous with other GPV/NGPV and Muscovy duck parvovirus (MDPV) strains. Phylogenetic analysis showed that the NGPV isolated from mainland China was related to the Taiwan 82-0321v strain of GPV. In contrast to 82-0321v and the SDLC01 strain, which was first isolated from China, the two isolates showed no deletions in the inverted terminal repeat (ITR) region. Further, in these isolates, 24 amino acid sites of the replication protein were different compared to that of GPV live vaccine strain 82-0321v, and 12 sites were unique across all NGPV isolates. These isolates also showed differences in 17 amino acid sites of the capsid protein from that of 82-0321v, two of which were the same as those in MDPV. Recombination analysis identified the major parents of GDSG1901 and GDQY1802 as the NGPV-GD and NGPV-Hun18 strains, and the minor parents as the classical GPV 06-0329 and GPV LH strains, respectively. GDQY1802 and GDSG1901 are recombinant GPV-related parvovirus isolated from domesticated partridge duck. Recombination is evident in the evolution of NGPV, and as such, the use of live attenuated vaccines for NGPV requires further study.

Three-dimensional metal-organic framework derived porous CoP3 concave polyhedrons as superior bifunctional electrocatalysts for the evolution of hydrogen and oxygen.

Developing low-cost and highly-efficient non-precious metal bifunctional electrocatalysts towards the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an attractively alternative strategy to solve the environmental pollution problems and energy demands. In this study, metal-organic framework (MOF) derived porous cobalt poly-phosphide (CoP3) concave polyhedrons are prepared and explored as superior bifunctional electrocatalysts for the HER and OER. The prepared MOF derived CoP3 concave polyhedrons show excellent electrocatalytic activity and stability towards the HER and OER in both acidic and alkaline media, with the Tafel slopes of 53 mV dec-1 and 76 mV dec-1 and a current density of 10 mA cm-2 at the overpotentials of -78 and 343 mV for the HER and OER, respectively, which are remarkably superior to those of the transition metal phosphides (TMPs) and comparable to those of the commercial precious metal catalysts. In addition, they also offer efficient catalytic activities and durabilities under neutral and basic conditions for the HER. The results of our study may shed light on the direction towards highly efficient bifunctional TMP electrocatalysts with high phosphorous component.

A two-stage hybrid approach for complex aortic coarctation combined with ascending-descending aorta dilatation and concomitant aortic valve regurgitation.

We present a case of aortic coarctation combined with ascending-descending aorta dilatation and concomitant aortic valve regurgitation. The technique involved using endovascular stenting, a two-stage balloon dilation procedure post-stent implantation and a Bentall procedure.

The influence of body composition on the N-terminal pro-B-type natriuretic peptide level and its prognostic performance in patients with acute coronary syndrome: a cohort study.

BACKGROUND: Whether body composition is associated with the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and its prognostic performance in acute coronary syndrome (ACS) remains unknown. We aimed to investigate the influence of body composition on the NT-proBNP level and its prognostic performance among ACS patients. METHODS: In total, 1623 ACS patients with NT-proBNP data were enrolled. Percent body fat and lean mass index were estimated using the Clínica Universidad de Navarra-Body Adiposity Estimator equation. Patients were divided into three groups according to the tertiles of sex-specific body mass index, percent body fat, or lean mass index. The endpoints were death from any cause and cardiovascular death. RESULTS: Body mass index was inversely correlated with NT-proBNP levels (ß = -0.036, P = 0.003). Lean mass index, but not percent body fat, was inversely associated with NT-proBNP levels (ß of lean mass index = -0.692, P = 0.002). During a median follow-up of 23 months, 161 all-cause deaths occurred, and of these, 93 (57.8 %) were attributed to cardiovascular causes. Multivariate Cox analysis showed that the NT-proBNP level independently predicted all-cause mortality or cardiovascular death in the lower body mass index, lean mass index, and percent body fat groups. However, the prognostic performance of NT-proBNP was attenuated in patients with high body mass index, lean mass index, and percent body fat. In the subgroup of patients with diabetes, inverse associations between NT-proBNP levels and body mass index or body composition were not observed. In addition, the negative influence of high body mass index and body composition on the prognostic performance of the NT-proBNP level appeared to be attenuated. CONCLUSIONS: Body mass index and lean mass index, but not percent body fat, are inversely associated with NT-proBNP levels. The prognostic performance of this biomarker may be compromised in patients with high body mass index, percent body fat, or lean mass index. Additionally, the influence of body composition on the NT-proBNP level and its prognostic performance might be attenuated in diabetic patients with ACS.

Amplified spontaneous emission from DCJTB encapsulated in mesostructured composite silica SBA-15.

Amplified spontaneous emission (ASE) characteristics of a red dye 4-(Dicyanomethylene)-2-t-butyl-6-(1,1,7,7- etramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) encapsulated in a highly ordered mesoporous SBA-15 were studied. The mesoporous composite silica film loaded with organic dye has been successfully synthesized by a solgel reaction process and a simple postgrafting method at room temperature. The spectrum narrowing phenomena has been observed when the composite film is pumped at λp=532 nm by a Nd:YAG ed laser. There is a substantial reduction in the full width at half-maximum of the emitting light, which is one of the signatures of the presence of ASE. The ASE threshold and net gain, respectively, reached 0.03 mJ pulse-1 and 34.7 cm-1 for the DCJTB encapsulated in mesoporous SBA-15 film. The optimized ASE properties owe much to the effects of the better spatial confinement of the molecules in the ordered mesoporous structure of the host SBA-15.

Developmental Trajectories and Predictors of Prosocial Behavior Among Adolescents Exposed to the 2008 Wenchuan Earthquake.

This longitudinal study examined the developmental trajectories of prosocial behavior and related predictors among adolescents exposed to the 2008 Wenchuan earthquake. At 6-, 18-, and 30-months postearthquake, we followed a sample of 1,573 adolescents. Self-report measures were used to assess earthquake exposure, postearthquake negative life events, prosocial behavior, symptoms of posttraumatic stress disorder, depression, anxiety, social support, and coping style. Data were analyzed using growth mixture modeling and multinomial logistic regressions. Four trajectories of postearthquake prosocial behavior were identified in the sample: (a) high/enhancing (35.0%), (b) high/stable (29.4%), (c) low/declining (33.6%), and (d) low/steeply declining (2.0%). Female gender, more social support, and greater positive coping were significant factors related to a higher probability of developing the high/enhancing trajectory. These findings may be helpful for us to identify adolescents with poor prosocial behavior after exposure to earthquakes so as to provide them with appropriate intervention.

Association Between Bisphosphonates Therapy and Incident Myocardial Infarction: Meta-analysis and Trial Sequential Analysis.

BACKGROUND: Bisphosphonates have shown potential to inhibit atherosclerosis in animal experiments; however, whether bisphosphonates therapy lowers the risk of incidence of myocardial infarction (MI) is debated. We performed the meta-analysis and trial sequential analysis (TSA) to investigate the relation between bisphosphonates therapy and incident MI. METHODS: Pubmed and Embase databases were systematically searched in April 2015 to identify studies, which compared the incidence of MI in subjects receiving bisphosphonates with that in subjects not receiving the agents. Meta-analysis was conducted using random effects model in consideration of statistical heterogeneity between studies. Reliability of the results from meta-analysis was examined using TSA. RESULTS: Six observational studies (n = 440261) and 3 randomized control trials (RCTs, n = 11,024) met the eligible criteria. In the pooled analysis of observational studies, bisphosphonates therapy was not associated with reduced risk of MI either using unadjusted estimates (relative risk 0.93, 95% confidence interval (CI), 0.75-1.15) or estimates adjusted for confounding factors (hazard ratio 1.01, 95% CI, 0.84-1.21). Furthermore, hazard of incident MI did not differ between alendronate users and nonusers. TSA showed that evidence from observational studies firmly precluded the association between bisphosphonates and incident MI. Pooled analysis of RCTs also suggested no benefits of decrease in incident MI associated with bisphosphonates therapy (relative risk 1.05, 95% CI, 0.53-2.09). However, TSA demonstrated that evidence from RCTs was insufficient to draw a conclusion. CONCLUSIONS: Despite the encouraging findings from animal studies, bisphosphonates therapy is not associated with reduced risk of MI.

Kinetic and isotherms studies of phosphorus adsorption onto natural riparian wetland sediments: linear and non-linear methods.

Riparian wetlands provide critical functions for the improvement of surface water quality and storage of nutrients. Correspondingly, investigation of the adsorption characteristic and capacity of nutrients onto its sediments is benefit for utilizing and protecting the ecosystem services provided by riparian areas. The Langmuir and Freundlich isotherms and pseudo-second-order kinetic model were applied by using both linear least-squares and trial-and-error non-linear regression methods based on the batch experiments data. The results indicated that the transformations of non-linear isotherms to linear forms would affect the determination process significantly, but the non-linear regression method could prevent such errors. Non-linear Langmuir and Freundlich isotherms both fitted well with the phosphorus adsorption process (r (2) > 0.94). Moreover, the influences of temperature and ionic strength on the adsorption of phosphorus onto natural riparian wetland sediments were also studied. Higher temperatures were suitable for phosphorus uptake from aqueous solution using the present riparian wetland sediments. The adsorption capacity increased with the enhancement of ionic strength in agreement with the formation of inner-sphere complexes. The quick adsorption of phosphorus by the sediments mainly occurred within 10 min. The adsorption kinetic was well-fitted by pseudo-second-order kinetic model (r (2) > 0.99). The scanning electron microscopy (SEM) and Fourier transformation infrared (FT-IR) spectra analyses before and after phosphorus adsorption revealed the main adsorption mechanisms in the present system.

Optimization of lasing in an inverted-opal titania photonic crystal cavity as an organic solid-state dye-doped laser.

Lasing performance of a dye-doped laser by encapsulating orange fluorescent dye 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) with different concentrations in a highly ordered three-dimensional (3D) inverted-opal titania (TiO2) photonic crystal (PC) microcavity was studied. The lasing threshold and laser quality were improved by optimizing the concentration of the laser dye DCM. When the concentration of DCM is optimized to 10-4 mol/l, the photoluminescence (PL) efficiency of DCM is sufficient to achieve lasing emission and meanwhile no fluorescence quantum quenching occurs. Therefore, the emission spectrum was greatly narrowed and the threshold was significantly improved, which reached 0.8 mJ pulse-1 cm-2. Our findings are promising results toward the realization of fabricating a highly efficient low-threshold organic laser.

Optical performance of mesostructured composite silica film loaded with organic dye.

A mesoporous composite silica film loaded with organic dye has been successfully synthesized by a solgel reaction process and a simple postgrafting method at room temperature. The composite film was characterized by x-ray diffraction, transmission electron microscopy, UV-Vis, photoluminescence (PL) spectra, and laser performance, and the results confirmed the existence of dyes in the channels of the silica film. A blue-shift and fluorescence property in the PL spectrum was observed from the composite film compared with that of dye molecules in C2H5OH solution. The spectrum narrowing phenomena has been observed when the composite film is pumped at λp=355 nm by a Nd:YAG pulsed laser. A narrower, higher peak was observed in emission spectra from the mesostructured composite silica film compared with the PL spectrum of dye in C2H5OH solution. There is a substantial reduction in the full width at half-maximum of the emitting light, which results in peaks with linewidths of 26 nm or more. This collapse of the emission spectrum is one of the signatures of the presence of amplified spontaneous emission.