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Halide perovskite CsPbBr3 quantum dots (QDs) were synthesized via supersaturated recrystallization process and deposited on the surface of TiO2 microtubes forming local nano-heterostructures. Structural, morphological, and optical characterizations confirm the formation of heterostructures comprised of TiO2 microtube decorated with green-emitting CsPbBr3 nanocrystals. Optical characterizations reveal the presence of two band gap energies corresponding to CsPbBr3 (2.34 eV) and rutile-TiO2 (2.97 eV). Time-resolved photoluminescence decays indicate different charge dynamics when comparing both samples, revealing the interaction of CsPbBr3 QDs with the microtube surface and thus confirming the formation of local nano-heterostructures. The voltage-current measurements in the dark show an abrupt decrease in the electrical resistivity of the CsPbBr3/TiO2 heterostructure reaching almost 95% when compared with the pristine TiO2 microtube. This significant increase in the electrical conductivity is associated with charge transfer from perovskite nanocrystals into the semiconductor microtube, which can be used to fine tune its electronic properties. Besides controlling the electrical conductivity, decoration with semiconducting nanocrystals makes the hollow heterostructure photoluminescent, which can be classified as a multifunctionalization in a single device.

The past decade has witnessed tremendous advances in synthesis of metal halide perovskites and their use for a rich variety of optoelectronics applications. Metal halide perovskite has the general formula ABX3, where A is a monovalent cation (which can be either organic (e.g., CH3NH3+ (MA), CH(NH2)2+ (FA)) or inorganic (e.g., Cs+)), B is a divalent metal cation (usually Pb2+), and X is a halogen anion (Cl-, Br-, I-). Particularly, the photoluminescence (PL) properties of metal halide perovskites have garnered much attention due to the recent rapid development of perovskite nanocrystals. The introduction of capping ligands enables the synthesis of colloidal perovskite nanocrystals which offer new insight into dimension-dependent physical properties compared to their bulk counterparts. It is notable that doping and ion substitution represent effective strategies for tailoring the optoelectronic properties (e.g., absorption band gap, PL emission, and quantum yield (QY)) and stabilities of perovskite nanocrystals. The doping and ion substitution processes can be performed during or after the synthesis of colloidal nanocrystals by incorporating new A', B', or X' site ions into the A, B, or X sites of ABX3 perovskites. Interestingly, both isovalent and heterovalent doping and ion substitution can be conducted on colloidal perovskite nanocrystals. In this review, the general background of perovskite nanocrystals synthesis is first introduced. The effects of A-site, B-site, and X-site ionic doping and substitution on the optoelectronic properties and stabilities of colloidal metal halide perovskite nanocrystals are then detailed. Finally, possible applications and future research directions of doped and ion-substituted colloidal perovskite nanocrystals are also discussed.

Star-like block copolymer nanoreactor enables the crafting of dual-shelled perovskite nanocrystals with enhanced stabilities., The past few years have witnessed rapid advances in the synthesis of high-quality perovskite nanocrystals (PNCs). However, despite the impressive developments, the stability of PNCs remains a substantial challenge. The ability to reliably improve stability of PNCs while retaining their individual nanometer size represents a critical step that underpins future advances in optoelectronic applications. Here, we report an unconventional strategy for crafting dual-shelled PNCs (i.e., polymer-ligated perovskite/SiO2 core/shell NCs) with exquisite control over dimensions, surface chemistry, and stabilities. In stark contrast to conventional methods, our strategy relies on capitalizing on judiciously designed star-like copolymers as nanoreactors to render the growth of core/shell NCs with controlled yet tunable perovskite core diameter, SiO2 shell thickness, and surface chemistry. Consequently, the resulting polymer-tethered perovskite/SiO2 core/shell NCs display concurrently a stellar set of substantially improved stabilities (i.e., colloidal stability, chemical composition stability, photostability, water stability), while having appealing solution processability, which are unattainable by conventional methods.

Thermoelectric (TE) research is not only a course of materials by discovery but also a seedbed of novel concepts and methodologies. Herein, the focus is on recent advances in three emerging paradigms: entropy engineering, phase-boundary mapping, and liquid-like TE materials in the context of thermodynamic routes. Specifically, entropy engineering is underpinned by the core effects of high-entropy alloys; the extended solubility limit, the tendency to form a high-symmetry crystal structure, severe lattice distortions, and sluggish diffusion processes afford large phase space for performance optimization, high electronic-band degeneracy, rich multiscale microstructures, and low lattice thermal conductivity toward higher-performance TE materials. Entropy engineering is successfully implemented in half-Huesler and IV-VI compounds. In Zintl phases and skutterudites, the efficacy of phase-boundary mapping is demonstrated through unraveling the profound relations among chemical compositions, mutual solubilities of constituent elements, phase instability, microstructures, and resulting TE properties at the operation temperatures. Attention is also given to liquid-like TE materials that exhibit lattice thermal conductivity at lower than the amorphous limit due to intensive mobile ion disorder and reduced vibrational entropy. To conclude, an outlook on the development of next-generation TE materials in line with these thermodynamic routes is given.

Day-case mastectomy surgery provides benefits to both patients and hospitals. Key barriers are the use of a drain and the risk of postoperative seroma formation. We introduced the use of a tissue sealant (Artiss) into the surgical site (post-mastectomy without immediate reconstruction and postaxillary clearance) and evaluated its effect on our practice, particularly day-case rates. A prospective audit of 177 patients who underwent a simple mastectomy with or without axillary surgery, or axillary node clearance with or without breast-conserving surgery was conducted at a single surgical center in the UK between November 2015 and November 2016. Artiss was used in all operations and, where appropriate, the drain was omitted to facilitate day-case surgery. The clinical outcomes were compared between patients undergoing different operations and duration of hospital stay. There was no statistically significant difference between day-case patients and inpatients in seroma aspiration rates (24.5% and 21.7%, respectively; P = 0.381) or other complications (22.4% and 16.1%, respectively; P = 0.106). The day-case mastectomy rate increased from 3.9% in the first quarter to 45.5% in the final quarter, which was a significant increase reaching well beyond the national target. The use of Artiss enabled us to increase the drain-free day-case surgery rates over a 1-year period, exceeding the 30% target recommended by the British Association of Day Surgery. We did not observe any increase in patient morbidity, and the change was cost-effective. We have now implemented the routine use of Artiss in women undergoing simple mastectomy with or without axillary surgery and stand-alone axillary node clearances as part of enhanced recovery clinical pathways.

Objective. To study the impact of geriatric assessment variables on 30-day mortality among older patients with acute heart failure (AHF). Methods. Retrospective analysis of cases in the OAK Registry (Older Acute Heart Failure Key Data), a prospectively compiled database of consecutive patients aged 65 years or older treated for AHF in 3 Spanish emergency departments over a 4-month period (November-December 2011 and January-February 2014). The patients underwent a geriatric assessment adapted for emergency department use on weekdays between 8 AM and 10 PM. Demographic, clinical, laboratory, and geriatric assessment variables were recorded. The geriatric variables were concurrent diseases; polypharmacy; frailty; functional, social, and cognitive status at baseline; results of screening for confusional state, cognitive impairment, and depression; and nutritional status. The primary outcome was all-cause mortality at 30 days. Results. We included 565 patients with a mean (SD) age of 83 (7.1) years; 346 (61.6%) were women. Sixty-five (11.5%) died within 30 days. Independent factors associated with 30-day mortality were acute confusional state (adjusted odds ratio [aOR], 2.2; 95% CI, 1.0-4.8; P=.04), acute illness (aOR, 1.8; 95% CI, 0.9-3.4; P=.05), loss of appetite in the past 3 months (aOR, 1.8; 95% CI, 1.0-3.4; P=.04), frailty (aOR, 2.0, 95% CI, 1.0-4.1; P=.05), and severe disability (aOR, 4.4; 95% CI, 1.9-11.4; P=.01). Conclusions. Certain geriatric variables should be considered when assessing short-term risk in older patients with AHF.