A Photoisomerization-Activated Intramolecular Charge-Transfer Process for Broadband-Tunable Single-Mode Microlasers.

Miniaturized lasers with high spectral purity and wide wavelength tunability are crucial for various photonic applications. Here we propose a strategy to realize broadband-tunable single-mode lasing based on a photoisomerization-activated intramolecular charge-transfer (ICT) process in coupled polymer microdisk cavities. The photoisomerizable molecules doped in the polymer microdisks can be quantitatively transformed into a kind of laser dye with strong ICT character by photoexcitation. The gain region was tailored over a wide range through the self-modulation of the optically activated ICT isomers. Meanwhile, the resonant modes shifted with the photoisomerization because of a change in the effective refractive index of the polymer microdisk cavity. Based on the synergetic modulation of the optical gain and microcavity, we realized the broadband tuning of the single-mode laser. These results offer a promising route to fabricate broadband-tunable microlasers towards practical photonic integrations.

Experimentally Observed Reverse Intersystem Crossing-Boosted Lasing.

Thermally activated delayed-fluorescent (TADF) materials are anticipated to overcome triplet-related losses towards electrically driven organic lasers. Thus far, contributions from triplets to lasing have not yet been experimentally demonstrated owing to the limited knowledge about the excited-state processes. Herein, we experimentally achieve reverse intersystem crossing (RISC)-boosted lasing in organic microspheres with uniformly dispersed TADF emitters. In these materials, triplets are continuously converted to radiative singlets through RISC, giving rise to reduced losses in stimulated emission. The involvement of regenerated singlets in population inversion results in a thermally activated lasing; that is, the lasing intensity increases with increasing temperature, accompanied by accelerated depletion of the excited-state population. Benefiting from the suppression of triplet accumulations by RISC processes, a high-repetition-rate microlaser was achieved.

Fire-Retardant and Thermally Insulating Phenolic-Silica Aerogels.

Energy efficient buildings require materials with a low thermal conductivity and a high fire resistance. Traditional organic insulation materials are limited by their poor fire resistance and inorganic insulation materials are either brittle or display a high thermal conductivity. Herein we report a mechanically resilient organic/inorganic composite aerogel with a thermal conductivity significantly lower than expanded polystyrene and excellent fire resistance. Co-polymerization and nanoscale phase separation of the phenol-formaldehyde-resin (PFR) and silica generate a binary network with domain sizes below 20 nm. The PFR/SiO2 aerogel can resist a high-temperature flame without disintegration and prevents the temperature on the non-exposed side from increasing above the temperature critical for the collapse of reinforced concrete structures.

Ion-Catalyzed Synthesis of Microporous Hard Carbon Embedded with Expanded Nanographite for Enhanced Lithium/Sodium Storage.

Hard carbons attract myriad interest as anode materials for high-energy rechargeable batteries due to their low costs and high theoretical capacities; practically, they deliver unsatisfactory performance due to their intrinsically disordered microarchitecture. Here we report a facile ion-catalyzed synthesis of a phenol-formaldehyde resin-based hard-carbon aerogel that takes advantage of the chelation effect of phenol and Fe3+, which consists of a three-dimensionally interconnected carbon network embedded with hydrogen-rich, ordered microstructures of expanded nanographites and carbon micropores. The chelation effect ensures the homodispersion of Fe in the polymer segments of the precursor, so that an effective catalytic conversion from sp3 to sp2 carbon occurs, enabling free rearrangement of graphene sheets into expanded nanographite and carbon micropores. The structural merits of the carbon offer chances to achieve lithium/sodium storage performance far beyond that possible with the conventional carbon anode materials, including graphite and mesocarbon microbeads, along with fast kinetics and long cycle life. In this way, our hard carbon proves its feasibility to serve as an advanced anode material for high-energy rechargeable Li/Na batteries.

Effect of family resilience on subjective well-being in patients with advanced cancer: the chain mediating role of perceived social support and psychological resilience.

Purposes: Domestic and international research has found that patients with advanced cancer prioritize increasing their quality of life above extending their lives with simple or intensive treatments. The current study investigates the pathways to improve patients' sense of well-being from the family, social, and individual levels, that is to say, it investigates the mediating roles of comprehending social support as well as psychological resilience in the relationship between family resilience and subjective well-being, and it also provides references for future intervention. Method: The Family Resilience Questionnaire (FRQ), General Well-being Schedule (GWB), Perceived Social Support Scale (PSSS), and the Chinese version of the Cornor-Davidson Resilience Scale 10-item (CD-RISC) were all completed by 338 patients with advanced cancer who took part in the study. Results: The study's findings demonstrated a significant and positive correlation between family resilience, subjective well-being, perceived social support, and psychological resilience. Additionally, there was a significant direct effect of family resilience on subjective well-being as well as a mediating and chain mediating effect between perceived social support and psychological resilience. The findings of this study will be very helpful in the future when it comes to enhancing the quality of life for patients with advanced cancer through intervention. Conclusion: Subjective well-being can be influenced directly by the family resilience of advanced cancer patients, or indirectly through the psychological resilience and perceived social support.

Chiral Hybrid Perovskite Single-Crystal Nanowire Arrays for High-Performance Circularly Polarized Light Detection.

Circularly polarized light (CPL) detection has emerged as a key technology for various optoelectronics. Chiral hybrid perovskites (CHPs) that combine CPL-sensitive absorption induced by chiral organic ligands and superior photoelectric properties of perovskites are promising candidates for direct CPL detection. To date, most of the CHP detectors are made up of polycrystalline thin-film, which results in a rather limited discrimination of CPL due to the existence of redundant impurities and intrinsic defect states originating from rapid crystallization process. Here, it is developed a direct CPL detector with high photocurrent and polarization selectivity based on low-defect CHP single-crystal nanowire arrays. Large-scale CHP nanowires are obtained through a micropillar template-assisted capillary-bridge rise approach. Thanks to the high crystallinity and ordered crystallographic alignment of these arrays, a CPL photodetector with high light on/off ratio of 1.8 × 104 , excellent responsivity of 1.4 A W-1 , and an outstanding anisotropy factor of 0.24 for photocurrent has been achieved. These results would provide useful enlightenment for direct CPL detection in high-performance chiral optoelectronics.

Tuneable red, green, and blue single-mode lasing in heterogeneously coupled organic spherical microcavities.

Tuneable microlasers that span the full visible spectrum, particularly red, green, and blue (RGB) colors, are of crucial importance for various optical devices. However, RGB microlasers usually operate in multimode because the mode selection strategy cannot be applied to the entire visible spectrum simultaneously, which has severely restricted their applications in on-chip optical processing and communication. Here, an approach for the generation of tuneable multicolor single-mode lasers in heterogeneously coupled microresonators composed of distinct spherical microcavities is proposed. With each microcavity serving as both a whispering-gallery-mode (WGM) resonator and a modulator for the other microcavities, a single-mode laser has been achieved. The colors of the single-mode lasers can be freely designed by changing the optical gain in coupled cavities owing to the flexibility of the organic materials. Benefiting from the excellent compatibility, distinct color-emissive microspheres can be integrated to form a heterogeneously coupled system, where tuneable RGB single-mode lasing is realized owing to the capability for optical coupling between multiple resonators. Our findings provide a comprehensive understanding of the lasing modulation that might lead to innovation in structure designs for photonic integration.