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Self‐trapped excitons (STEs) of lead‐free perovskites have aroused tremendous interest in remote optical thermometry due to strong exciton–phonon coupling and large Stokes shifts. Herein, a bright multimodal and multiplexed optical thermometer is constructed with high sensitivity (Sr) and self‐calibrating ability based on Cs2NaInCl6:Er3+ double perovskite, allowing for fast and simplified reading via mobile devices. Intriguingly, Er3+ doping not only shows the characteristic green emissions but also introduces nanoelectronic domains through a new localized valance band maximum and breaks the symmetry of In3+ site, which facilitates the generation of more STEs. The temperature‐sensitive blue emission of STEs and temperature‐insensitive green emission of Er3+ endow multimodal optical thermometry including time‐resolved and ratiometric readout schemes with a maximum Sr of 3.8% K−1, where an upconversion primary thermometry serves as a reference to calibrate other modes. Meanwhile, the designed thermometers show robust photostability, repeatability, and structural stability for long‐time working and storage. In addition, the remarkable thermochromic phenomenon from blue to green enables a quick color‐multiplexed thermography on a smartphone, which is utilized to capture real‐time 2D thermal imaging of microelectronic devices. This work demonstrates the great potential of lead‐free double perovskite for low‐cost and portable optical thermometry. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) reinforced polymer nanocomposites with high thermal conductivity show a promising prospect in thermal management of next‐generation electronic devices due to their excellent mechanical adaptability, outstanding processability, and superior flexibility. However, interfacial thermal resistance between individual CNT significantly hinders the further improvement in thermal conductivity of CNT‐reinforced nanocomposites. Herein, an interfacial welding strategy is reported to construct graphitic structure welded CNT (GS‐w‐CNT) networks. Notably, the obtained GS‐w‐CNT/polydimethylsiloxane (PDMS) nanocomposite with a GS loading of 4.75 wt% preserves a high thermal conductivity of 5.58 W m−1 K−1 with a 410% enhancement as compared to a pure CNT/PDMS nanocomposite. Molecular dynamics simulations are utilized to elucidate the effect of interfacial welding on the heat transfer behavior, revealing that the GS welding degree plays an important role in reducing both phonon scattering in the GS‐w‐CNT structure and interfacial thermal resistance at the interfaces between CNT. The unique welding strategy provides a new route to optimize the thermal transport performance in filler reinforced polymer nanocomposites, promoting their applications in next‐generation microelectronic devices. [ABSTRACT FROM AUTHOR]

The growth of Na‐dendrites and the dissolution of organic cathodes are two major challenges that hinder the development of sodium‐organic batteries (SOBs). Herein, a multifunctional Janus separator (h‐BN@PP@C) by using an interfacial engineering strategy, is proposed to tackle the issues of SOBs. The carbon layer facing the organic cathode serves as a barrier to capture dissolved organic materials and enhance their utilization. Meanwhile, the h‐BN layer facing the Na anode possesses high thermal conductivity and mechanical strength, which mitigates the occurrence of localized‐temperature "hot spots" and promotes the formation of a NaF‐enriched SEI, thereby suppressing dendrite growth. Consequently, the Janus separator enables a stable Na plating/stripping cycling for 1000 h at 3 mA cm−2. Equipped with the Janus separator, organic cathodes including dibenzo[b,i]thianthrene‐5,7,12,14‐tetraone (DTT), pentacene‐5,7,12,14‐tetrone and Calix[4]quinone cathodes demonstrate high capacity and remarkable cycling performance. In particular, the DTT exhibits a bipolar co‐reaction storage mechanism and achieves an ultrahigh capacity (≈342.6 mAh g−1), long‐term cycling stability (capacity decay rate of 0.15% per cycle over 550 cycles at 500 mA g−1) and fast kinetics (1000 mA g−1≈2.8 C). This study offers a straightforward, effective, and promising solution to address the challenges in SOBs. [ABSTRACT FROM AUTHOR]

Photocatalytic conversion of H2O and CO2 into solar fuels is considered to be a green and renewable technology while photocatalytic performance is hampered by the severe recombination of photogenerated electron–hole pairs. Drawing inspiration from the concepts of the electrons transfer layer (ETL) and the holes transfer layer (HTL) in perovskite solar cells, a multicomponent photocatalyst SrTiO3/NiO/NiS that incorporates p–n heterojunction and Schottky junction is constructed for converting solar energy into easily storable solar fuels. The NiS and NiO play the roles analogy to the ETL and the HTL which accomplishes the reverse migration of electrons and holes, accordingly, SrTiO3/NiO/NiS exhibits a noticeable enhancement in photocatalytic performance. However, the lack of direct observation of charge transfer pathways in complex multicomponent photocatalysts makes it challenging to thoroughly investigate their catalytic mechanisms. Herein, the in situ irradiation X‐ray photoelectron spectroscopy (ISI–XPS) is employed to track photogenerated charges migration pathways between microscopic heterogeneous interfaces, thereby providing a comprehensive elucidation of the catalytic mechanism and heterojunction formation process by integrating the photoelectrochemical tests. This study not only serves as compelling evidence for the capability of ISI–XPS in directly and accurately tracking charge transfer pathways but also as an intriguing highlight within the catalyst design strategy. [ABSTRACT FROM AUTHOR]

The rapidly increasing solar conversion efficiency (PCE) of hybrid organic–inorganic perovskite (HOIP) thin‐film semiconductors has triggered interest in their use for direct solar‐driven water splitting to produce hydrogen. However, application of these low‐cost, electronic‐structure‐tunable HOIP tandem photoabsorbers has been hindered by the instability of the photovoltaic‐catalyst‐electrolyte (PV+E) interfaces. Here, photolytic water splitting is demonstrated using an integrated configuration consisting of an HOIP/n+silicon single junction photoabsorber and a platinum (Pt) thin film catalyst. An extended electrochemical (EC) lifetime in alkaline media is achieved using titanium nitride on both sides of the Si support to eliminate formation of insulating silicon oxide, and as an effective diffusion barrier to allow high‐temperature annealing of the catalyst/TiO2‐protected‐n+silicon interface necessary to retard electrolytic corrosion. Halide composition is examined in the (FA1‐xCsx)PbI3 system with a bandgap suitable for tandem operation. A fill factor of 72.5% is achieved using a Spiro‐OMeTAD‐hole‐transport‐layer (HTL)‐based HOIP/n+Si solar cell, and a high photocurrent density of −15.9 mA cm−2 (at 0 V vs reversible hydrogen electrode) is attained for the HOIP/n+Si/Pt photocathode in 1 m NaOH under simulated 1‐sun illumination. While this thin‐film design creates stable interfaces, the intrinsic photo‐ and electro‐degradation of the HOIP photoabsorber remains the main obstacle for future HOIP/Si tandem PEC devices. [ABSTRACT FROM AUTHOR]

CsPbBr3 quantum dots (QDs) prepared through traditional hot‐injection and room temperature reprecipitation methods are usually hexahedral (nanoplate/cube) and green‐emitting. These methods severely obstruct the development of blue perovskite‐based light‐emitting diodes (PeLEDs) because the resultant QDs always suffer unachievable morphology regulation. Here, highly efficient blue‐emitting rhombic dodecahedron CsPbBr3 QDs (CsPbBr3 <12> QDs) are obtained by regulating morphological transformation for the first time through a novel and facile sequential post‐treatment strategy. Hydrobromide (‐NH3+) with stronger adsorption energy promotes the morphology transform of QDs from nanoplate to cube by substituting oleylamine in the first step. Then, polar solvent vapor eliminates PbX64− and led to the (112) crystal plane of the cube QDs being exposed, which is effectively stabilized by ‐NH3+ to realize morphology transition from cube to the dodecahedron. Highly efficient 12‐faceted dodecahedrons are endowed with significantly enhanced photoluminescence quantum yield of 89.8% at 476 nm as well as uniform size distribution and mono‐dispersity. The target blue PeLEDs achieve the maximum external quantum efficiency of 6.6% (480 nm) and excellent spectrum stability. This study provides a new strategy to prepare blue‐emitting CsPbBr3 <12> QDs by delicate control toward the growth and polyhedron process of crystal. [ABSTRACT FROM AUTHOR]

The development of efficient and long‐term stable electrodes for hydrogen evolution reaction (HER) in seawater is highly desirable for hydrogen generation but remains challenging. In this work, a highly active CrOx@Ni2P‐Ni5P4/NF electrode is developed and investigated its dynamic reconstruction for HER in neutral electrolytes. The combination of in situ Raman spectra and electrochemical measurements revealed the dynamic surface reconstruction of the catalyst during HER. The CrOx modification not only effectively facilitates water dissociation but also stabilizes the structure post‐reconstruction, enabling rapid and stable hydrogen generation in neutral media. Remarkably, CrOx@Ni2P‐Ni5P4/NF exhibits overpotentials of 109 and 263 mV at current densities of 10 and 100 mA cm−2 in 1 m PBS, respectively. Concurrently, it exhibits stable operation for 500 h in 1 m PBS and 140 h in natural seawater at current densities of 50 and 100 mA cm−2, respectively. The proposed catalytic electrode and the mechanistic insights present a significant stride toward the realization of metal phosphides for direct seawater splitting. [ABSTRACT FROM AUTHOR]