Pressure Coupled Lanthanide Ion Doping to Enhance Optical Properties in BaTiO3.

Self-trapped excitons (STEs) typically give broadband photoluminescence emission with a large Stokes shift, which is important for the enhancement of the optical properties of materials. Here, low-dimensional La-doped BaTiO3 nanocrystals with defects are prepared using supercritical CO2 (SC CO2). The generation of the STEs is facilitated by doping La3+ ions and introducing CO2 pressure, which effectively enhance the luminescence intensity of BaTiO3. This discovery shows that the La ion doping concentration can modulate the photoluminescence of BaTiO3 nanocrystals under pressure. This work deepens the understanding of the influence of rare-earth-doped luminescent materials under pressure and provides insight to improve the capabilities of optical devices.

Interfacial Bonding Induced Charge Transfer in Two-Dimensional Amorphous MoO3-x/Graphdiyne Oxide Non-Van der Waals Heterostructures for Dominant SERS Enhancement.

Two-dimensional semiconductor-based nanomaterials have shown to be an effective substrate for Surface-enhanced Raman Scattering (SERS) spectroscopy. However, the enhancement factor (EF) tends to be relatively weak compared to that of noble metals and does not allow for trace detection of molecules. In this work, we report the successful preparation of two-dimensional (2D) amorphous non-van der Waals heterostructures MoO3-x/GDYO nanomaterials using supercritical CO2. Due to the synergistic effect of the localized surface plasmon resonance (LSPR) effect and the charge transfer effect, it exhibits excellent SERS performance in the detection of methylene blue (MB) molecules, with a detection limit as low as 10-14 M while the enhancement factor (EF) can reach an impressive 2.55×1011. More importantly, the chemical bond bridging at the MoO3-x/GDYO heterostructures interface can accelerate the electron transfer between the interfaces, and the large number of defective surface structures on the heterostructures surface facilitates the chemisorption of MB molecules. And the charge recombination lifetime can be proved by a ~1.7-fold increase during their interfacial electron-transfer process for MoO3-x/GDYO@MB mixture, achieving highly sensitive SERS detection.

Linkage-Mediated Electronic Structure Modulation in Multicomponent Covalent Organic Frameworks for Dramatically Promoted Photocatalytic Hydrogen Evolution.

Linkage chemistry is an essential aspect to covalent organic framework (COF) applications; it is highly desirable to precisely modulate electronic structure mediated directly by linkage for efficient COF-based photocatalytic hydrogen evolution, which however, remains substantially challenging. Herein, as a proof of concept, a collection of robust multicomponent pyrene-based COFs with abundant donor-acceptor (D-A) interactions has been judiciously designed and synthesized through molecularly engineering linkage for photogeneration of hydrogen. Controlled locking and conversion of linkage critically contribute to continuously regulating COFs' electronic structures further to optimize photocatalytic activities. Remarkably, the well-modulated optoelectronic properties turn on the average hydrogen evolution rate from zero to 15.67 mmol g-1 h-1 by the protonated quinoline-linked COF decorated with the trifluoromethyl group (TT-PQCOF-CF3). Using diversified spectroscopy and theoretical calculations, we show that multiple modifications toward linkage synergistically lead to the redistribution of charge on COFs with extended π-conjugation and reinforced D-A effect, making TT-PQCOF-CF3 a promising material with significantly boosted carrier separation and migration. This study provides important guidance for the design of high-performance COF photocatalysts based on the strategy of linkage-mediated electronic structure modulation in COFs.

Structural Engineering of BiVO4 /CoFe MOF Heterostructures Boosting Charge Transfer for Efficient Photoelectrochemical Water Splitting.

Boosting charge separation and transfer of photoanodes is crucial for providing high viability of photoelectrochemical hydrogen (H2 ) generation. Here, a structural engineering strategy is designed and synthesized for uniformly coating an ultrathin CoFe bimetal-organic framework (CoFe MOF) layer over a BiVO4 photoanode for boosted charge separation and transfer. The photocurrent density of the optimized BiVO4 /CoFe MOF(NA) photoanode reaches a value of 3.92 mA cm-2 at 1.23 V versus reversible hydrogen electrode (RHE), up to 6.03 times that of pristine BiVO4 , due to the greatly increased efficiency of charge transfer and separation. In addition, this photoanode records one onset potential that is considerably shifted negatively when compared to BiVO4 . Transient absorption spectroscopy reveals that the CoFe MOF(NA) prolongs charge recombination lifetime by blocking the hole-transfer pathway from the BiVO4 to its surface trap states. This work sheds light on boosting charge separation and transfer through structural engineering to enhance the photocurrent of photoanodes for solar H2 production.

Development of the Colorimetric and/or Fluorescent Probes for Detecting Fluoride ions in Aqueous Solution.

Fluoride ion is a strong Lewis base and one of the essential trace elements in human body. It plays a very important role in human health and ecological balance. The deficiency or excessive intake of fluoride ions will cause serious health problems, so the development of a sensitive and accurate detection method for fluoride ions is very important. The colorimetric and/or fluorescence sensing method has been a long standing attractive technique with high sensitivity and fast response. To date, most reported probes for fluoride ion are applicable only in organic solvents or organic-containing aqueous solutions. However, the probes for fluoride ion used in aqueous solution are more practically needed in view of environment protection and human health. In this paper, the materials and designing ideas of the colorimetric and/or fluorescent probes for fluoride ion based on different detection mechanisms in recent years were reviewed. Two main categories including formation of hydrogen bonds and formation of coordination covalent bonds were discussed. The latter one is further subdivided into three types, formation of B-F bond, formation of Si-F bond and formation of Mn+-F bond.

Achiral-Core-Metal Change in Isomorphic Enantiomeric Ag12Ag32 and Au12Ag32 Clusters Triggers Circularly Polarized Phosphorescence.

Understanding how the chiral or achiral section in chiral nanostructures contributes to circularly polarized light emission (CPLE) at the atomic level is of fundamental importance. Here, we report two pairs of atomically precise enantiomers of homosilver (R/S-Ag12Ag32) and heterometal (R/S-Au12Ag32) clusters. The geometrical chirality of R/S-Ag12Ag32 arises from the chiral ligand and interface consisting of positive moieties of Ag32(R/S-PS)24. The circular dichroism of R/S-Ag12Ag32 is active, but CPLE-silent. A complete metal change from Ag12 to Au12 in the achiral core section of S2-@M12@S8 engenders isomorphous heterometal R/S-Au12Ag32, which activates CPLE. We further quantify the contributions of achiral and chiral sections and for the first time unveil that heterometal bonding (Au12-Ag32) at the linkage varies the delocalization of orbitals and proportion of achiral and chiral section in electron transition-involved orbitals, thus activating CPLE. Based on these unique atomically precise homochiral metal clusters, our work provides a new insight into the contributions of achiral and chiral sections to the origin of chiroptical response of chiral metal clusters, paving the way to advance the development of CPLE nanoparticles.

Tmc proteins are essential for zebrafish hearing where Tmc1 is not obligatory.

Perception of sound is initiated by mechanically gated ion channels at the tips of stereocilia. Mature mammalian auditory hair cells require transmembrane channel-like 1 (TMC1) for mechanotransduction, and mutations of the cognate genetic sequences result in dominant or recessive heritable deafness forms in humans and mice. In contrast, zebrafish lateral line hair cells, which detect water motion, require Tmc2a and Tmc2b. Here, we use standard and multiplex genome editing in conjunction with functional and behavioral assays to determine the reliance of zebrafish hearing and vestibular organs on Tmc proteins. Surprisingly, our approach using multiple mutant alleles demonstrates that hearing in zebrafish is not dependent on Tmc1, nor is it fully dependent on Tmc2a and Tmc2b. Hearing however is absent in triple-mutant zebrafish that lack Tmc1, Tmc2a and Tmc2b. These outcomes reveal a striking resemblance of Tmc protein reliance in the vestibular sensory epithelia of mammals to the maculae of zebrafish. Moreover, our findings disclose a logic of Tmc use where hearing depends on a complement of Tmc proteins beyond those employed to sense water motion.

Multiple-cation wide-bandgap perovskite solar cells grown using cesium formate as the Cs precursor with high efficiency under sunlight and indoor illumination.

Owing to the advantages of adjustable bandgap, low-cost fabrication and superior photovoltaic performance, wide-bandgap (WBG) perovskite solar cells (PSCs) are considered as the promising top-cell for multi-junction solar cells. At the same time, WBG PSCs have also shown great potential for indoor photovoltaic applications. To further improve the performance of WBG PSCs, in this work, we fabricated efficient WBG PSCs via introducing cesium formate (CsFa) as the Cs precursor. Due to the HCOO·Pb+ and HCOOH·Cs+ complex formation and HCOOH volatilization accompanying the crystallization process, the crystallization of the perovskite using the CsFa precursor (CsFa-perovskite) is promoted. Compared to the perovskite prepared using the CsBr precursor (CsBr-perovskite), the WBG CsFa-perovskite shows better perovskite crystallization, reduced trap-state density, and better phase stability under light illumination. Finally, the 1.63 eV WBG PSCs based on the CsFa-perovskite achieve a significant PCE of 20.01% under one sun illumination (AM 1.5G, 100 mW cm-2), which is higher than that of PSCs based on the CsBr-perovskite (18.27%). Moreover, the PCE of CsFa-perovskite PSCs also under indoor warm-white 2700 K LED light illumination (1000 lux) is as high as 38.52%. Our results demonstrate that CsFa as the Cs precursor is a promising candidate to promote the device performance of WBG PSCs.

Ultrafast photophysical process of bi-exciton Auger recombination in CuInS2 quantum dots studied by transient-absorption spectroscopy.

Auger recombination is an ultrafast and unnegligible photophysical process in colloidal semiconductor quantum dots (QDs) due to competition with charge separation or radiative recombination processes, pivotal for their applications ranging from bio-labeling, light-emitting diodes, QD lasing to solar energy conversion. Among diverse QDs, ternary chalcopyrite is recently receiving significant attention for its heavy-metal free property and remarkable optical performance. Given deficient understanding of the Auger process for ternary chalcopyrite QDs, CuInS2 QDs with various sizes are synthesized as a representative and the bi-exciton lifetime (τBX) is derived by virtue of ultrafast time resolved absorption spectrum. The trend of τBX varying with size is consistent with the universal scaling of τBX versus QD volume (V): τBX = γV. The scaling factor γ is 6.6 ± 0.5 ps·nm-3 for CuInS2 QDs, and the bi-exciton Auger lifetime is 4-5 times slower than typical CdSe QDs with the same volume, suggesting reduced Auger recombination rate in ternary chalcopyrite. This work facilitates clearer understanding of Auger process and provides further insight for rational design of light-harvesting and emitting devices based on ternary chalcopyrite QDs.

Unravelling the Synergy between Oxygen Vacancies and Oxygen Substitution in BiO2-x for Efficient Molecular-Oxygen Activation.

Defects in nanomaterials often lead to properties that are absent in their pristine counterparts. To date, most studies have focused on the effect of single defects, while ignoring the synergy of multiple defects. In this study, a model of photocatalytic O2 activation was selected to unravel the role of dual defects by decorating bismuth oxide with surface O vacancies and bulk O substitution simultaneously. The introduction of dual defects led to a spatial and electronic synergistic process: i) O substitution induced a local electric field in the bulk of BiO2-x , which promoted bulk separation of electrons and holes immediately after their generation; ii) O vacancies efficiently lowered the conduction band, served as the capture center for electrons, and thus facilitated the adsorption and activation of O2 . This effect was greatly promoted by the coexistence of bulk O substitution, and DFT calculations showed that only O substitution near an O vacancy could have this effect.

Triplet Sensitization by "Self-Trapped" Excitons of Nontoxic CuInS2 Nanocrystals for Efficient Photon Upconversion.

Triplet energy transfer (TET) from semiconductor nanocrystals (NCs) has recently emerged as a new triplet sensitization paradigm. It remains unclear how trap states pervasive in NCs influence TET or whether trapped excitons can undergo efficient TET. Here we partially address this issue by studying TET from CuInS2 NCs as a model system because their photogenerated excitons are known to be "self-trapped" due to hole localization to intragap Cu states. We found that, thanks to the long lifetime (209 ± 17 ns) of self-trapped excitons, they could be extracted with an efficiency of ∼92.3% by surface-anchored anthracene despite that the TET rate was relatively slow (57.1 ± 1.7 µs-1). We further leveraged this efficient sensitization to achieve triplet-triplet-annihilation photon upconversion (TTA-UC) with a quantum yield of 18.6 ± 0.3%. Thus, this study not only demonstrates trapped excitons can undergo efficient TET as well, but also presents the first TTA-UC system sensitized by nontoxic NCs which is important for the real-life application of this technique.

Ribeye protein is intrinsically dynamic but is stabilized in the context of the ribbon synapse.

KEY POINTS: The synaptic ribbon is an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance. Ribeye a and b proteins are major constituents of the synaptic ribbon in hair cells. In this study, we use optically clear transgenic zebrafish to examine the potential dynamics of ribeye proteins in vivo. We demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of hair cells in the ear and the lateral line system. ABSTRACT: Ribeye protein is a major constituent of the synaptic ribbon, an organelle that coordinates rapid and sustained vesicle release to enable hearing and balance. The ribbon is considered to be a stable structure. However, under certain physiological conditions such as acoustic overexposure that results in temporary noise-induced hearing loss or perturbations of ion channels, ribbons may change shape or vanish altogether, suggesting greater plasticity than previously appreciated. The dynamic properties of ribeye proteins are unknown. Here we use transgenesis and imaging to explore the behaviours of ribeye proteins within the ribbon and also their intrinsic properties outside the context of the ribbon synapse in a control cell type, the skin cell. By fluorescence recovery after photobleaching (FRAP) on transgenic zebrafish larvae, we test whether ribeye proteins are dynamic in vivo in real time. In the skin, a cell type devoid of synaptic contacts, Ribeye a-mCherry exchanges with ribbon-like structures on a time scale of minutes (t1/2  = 3.2 min). In contrast, Ribeye a of the ear and lateral line and Ribeye b of the lateral line each exchange at ribbons of hair cells an order of magnitude slower (t1/2 of 125.6 min, 107.0 min and 95.3 min, respectively) than Ribeye a of the skin. These basal exchange rates suggest that long-term ribbon presence may require ribeye renewal. Our studies demonstrate that ribeye proteins are inherently dynamic but are stabilized at the ribbons of sensory cells in vivo.

A Nomogram to Predict Prognosis in Malignant Pleural Mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare malignancy with heterogeneous outcomes. This study was aimed to develop a nomogram to precisely and visually predict survival of MPM patients. METHODS: Data from Surveillance, Epidemiology, and End Results database (1973-2014) on MPM were screened and retrieved. The prognostic effects of variables, including age, sex, race, year of diagnosis, laterality, histology, tumor stage, surgery, chemotherapy, and radiotherapy were analyzed using Kaplan-Meier method and Cox proportional hazard model. A nomogram was formulated to predict overall survival of MPM patients. RESULTS: A total of 1092 cases who met inclusion criteria were included in this study. The overall 1-, 2-, and 3-year survival rate in the entire cohort was 45.1, 23.0, and 12.1%, with median survival of 11 months. Cox regression analysis showed that age (P < 0.001), race (P = 0.003), histology type (P < 0.001), T stage (P < 0.001), M stage (P < 0.001), TNM stage (P < 0.001), cancer-directed surgery (P < 0.001), and chemotherapy (P < 0.001) were all independent prognostic factors of MPM patients. A nomogram was established based on the results of multivariate analysis. The internal bootstrap resampling approach suggested the nomogram had sufficient discriminatory power with the C-index of 0.705 (95% CI 0.681-0.729). The calibration plots also demonstrated good consistence between the prediction and the observation. CONCLUSIONS: We developed a nomogram to accurately predict clinical outcomes of MPM patients based on individual characteristics. Risk stratification by the survival nomogram could optimize individual therapies and follow-up.

Experimental Identification of Ultrafast Reverse Hole Transfer at the Interface of the Photoexcited Methanol/Graphitic Carbon Nitride System.

An experimental scrutiny of the photoexcited hole dynamics in a prototypical system is presented in which hole-scavenging methanol molecules are chemisorbed on a graphitic carbon nitride (g-C3 N4 ) substrate. A set of comparison and control experiments by means of femtosecond time-resolved transient absorption (fs-TA) spectroscopy were conducted. The elusive reverse hole transfer (RHT) process was identified, which occurs on a timescale of a few hundred picoseconds. The critical role of interfacially chemisorbed methoxy (instead of methanol) as the dominant species responsible for hole scavenging was confirmed by a control experiment using protonated g-C3 N4 as the substrate. A hot-hole transfer effect was revealed by implementing different interband photoexcitation scenarios. The RHT rate is the key factor governing the hole-scavenging ability of different hole scavengers.

Defect-Mediated Electron-Hole Separation in One-Unit-Cell ZnIn2S4 Layers for Boosted Solar-Driven CO2 Reduction.

The effect of defects on electron-hole separation is not always clear and is sometimes contradictory. Herein, we initially built clear models of two-dimensional atomic layers with tunable defect concentrations, and hence directly disclose the defect type and distribution at atomic level. As a prototype, defective one-unit-cell ZnIn2S4 atomic layers are successfully synthesized for the first time. Aberration-corrected scanning transmission electron microscopy directly manifests their distinct zinc vacancy concentrations, confirmed by positron annihilation spectrometry and electron spin resonance analysis. Density-functional calculations reveal that the presence of zinc vacancies ensures higher charge density and efficient carrier transport, verified by ultrafast photogenerated electron transfer time of ∼15 ps from the conduction band of ZnIn2S4 to the trap states. Ultrafast transient absorption spectroscopy manifests the higher zinc vacancy concentration that allows for ∼1.7-fold increase in average recovery lifetime, confirmed by surface photovoltage spectroscopy and PL spectroscopy analysis, which ensures promoted carrier separation rates. As a result, the one-unit-cell ZnIn2S4 layers with rich zinc vacancies exhibit a carbon monoxide formation rate of 33.2 µmol g-1 h-1, roughly 3.6 times higher than that of the one-unit-cell ZnIn2S4 layers with poor zinc vacancies, while the former's photocatalytic activity shows negligible loss after 24 h photocatalysis. This present work uncovers the role of defects in affecting electron-hole separation at atomic level, opening new opportunities for achieving highly efficient solar CO2 reduction performances.

Visible-Light Photoexcited Electron Dynamics of Scandium Endohedral Metallofullerenes: The Cage Symmetry and Substituent Effects.

Endohedral metallofullerenes (EMFs) have become an important class of molecular materials for optoelectronic applications. The performance of EMFs is known to be dependent on their symmetries and characters of the substituents, but the underlying electron dynamics remain unclear. Here we report a systematic study on several scandium EMFs and representative derivatives to examine the cage symmetry and substituent effects on their photoexcited electron dynamics using ultrafast transient absorption spectroscopy. Our attention is focused on the visible-light (530 nm as a demonstration) photoexcited electron dynamics, which is of broad interest to visible-light solar energy harvesting but is considered to be quite complicated as the visible-light photons would promote the system to a high-lying energy region where dense manifolds of electronic states locate. Our ultrafast spectroscopy study enables a full mapping of the photoinduced deactivation channels involved and reveals that the long-lived triplet exciton plays a decisive role in controlling the photoexcited electron dynamics under certain conditions. More importantly, it is found that the opening of the triplet channels is highly correlated to the fullerene cage symmetry as well as the electronic character of the substituents.

Rupturing C60 Molecules into Graphene-Oxide-like Quantum Dots: Structure, Photoluminescence, and Catalytic Application.

The large-scale synthesis of graphene-oxide-like quantum dots (GOLQDs) is reported by oxidizing C(60) molecules using a modified Hummers method with a yield of ≈25 wt% readily achieved. The GOLQDs are highly soluble in water and in addition to hexagons have other carbon rings in the structure. They have an average height of ≈1.2 nm and a diameter distribution of 0.6-2.2 nm after drying on substrates. First-principle calculations indicate that a possible rupturing route may include the insertion of oxygen atoms to CC bonds in the C(60) molecule, followed by rupture of that CC bonds. The GOLQD suspension has a strong photoluminescence (PL) with peak position dependent on excitation wavelength. The PL is related to the size and emissive traps caused by oxygen-containing groups. The GOLQDs also catalyze the oxidation of benzyl alcohol with a high selectivity.

Bringing light into the dark triplet space of molecular systems.

A molecule or a molecular system always consists of excited states of different spin multiplicities. With conventional optical excitations, only the (bright) states with the same spin multiplicity of the ground state could be directly reached. How to reveal the dynamics of excited (dark) states remains the grand challenge in the topical fields of photochemistry, photophysics, and photobiology. For a singlet-triplet coupled molecular system, the (bright) singlet dynamics can be routinely examined by conventional femtosecond pump-probe spectroscopy. However, owing to the involvement of intrinsically fast decay channels such as intramolecular vibrational redistribution and internal conversion, it is very difficult, if not impossible, to single out the (dark) triplet dynamics. Herein, we develop a novel strategy that uses an ultrafast broadband white-light continuum as a excitation light source to enhance the probability of intersystem crossing, thus facilitating the population flow from the singlet space to the triplet space. With a set of femtosecond time-reversed pump-probe experiments, we report on a proof-of-concept molecular system (i.e., the malachite green molecule) that the pure triplet dynamics can be mapped out in real time through monitoring the modulated emission that occurs solely in the triplet space. Significant differences in excited-state dynamics between the singlet and triplet spaces have been observed. This newly developed approach may provide a useful tool for examining the elusive dark-state dynamics of molecular systems and also for exploring the mechanisms underlying molecular luminescence/photonics and solar light harvesting.

WHO histological classification and tumor size are predictors of the locally aggressive behavior of thymic epithelial tumors.

OBJECTIVE: The aim of this study was to explore the influencing factors that affect the local invasive behavior of thymic epithelial tumors (TETs). METHOD: We retrospectively analyzed 524 patients with TETs who underwent surgical treatment at our center from January 2010 to January 2022. Cox regression analysis was applied to identify predictors associated with the prognosis of TET. Logistic regression analysis was used to analyze the factors associated with the locally invasive behavior of TETs. Receiver operating characteristic analysis and the Youden index were applied to determine the predictive efficiency and cutoff value. RESULTS: There were 275 males and 249 females with a median age of 56 years. Seventy-seven patients had locally invasive behavior. The prognosis of local invasive TETs was significantly worse that of noninvasive TETs (P < 0.001). WHO classification and tumor size were two hazard factors for tumor invasive behavior. The risk of local invasion increased by 2.196 (OR (95 % CI): 1.813-2.659) times for each grade in WHO classification with a change from type A to thymic carcinoma. The tumor size cutoff of 6 cm represented a distinct boundary in predicting the hazard of local invasion (AUC: 0.784, specificity: 0.711, sensitivity: 0.726). CONCLUSION: WHO classification and tumor size are important factors in predicting the locally aggressive behavior of TETs. The invasion capability of TETs is constantly increasing with an escalation in WHO classification. Tumors greater than 6 cm in size have a higher risk for local invasion.

Ecological risk assessment of dissolved heavy metals in the Yangtze River Estuary and Zhejiang coastal waters, China.

The study applied a tiered ecological risk assessment method to evaluate the long-term status and trend of the ecological risks of dissolved heavy metals from 2011 to 2019 in the Yangtze River Estuary and Zhejiang coastal waters, China. The results for spring, summer, and autumn of 2019 indicated that Pb, Cd, and Zn posed no adverse ecological risk, Cu posed a potential ecological risk, and As posed an ecological risk. The annual results from 2011 to 2019 suggested that Pb, Cd, and Zn posed no adverse ecological risks, and As and Cu posed an ecological risk. The trend analysis in the nine years showed that the ecological risk of Cu is gradually decreasing, while that of As is still a concern. The overall trend is attributed to the environmental protection policies that reduced these contaminants' terrestrial sources and atmospheric sources.