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The oxygen evolution reaction (OER) underpins many aspects of energy storage and conversion in modern industry and technology, but which still be suffering from the dilemma of sluggish reaction kinetics and poor electrochemical performance. Different from the viewpoint of nanostructuring, this work focuses on an intriguing dynamic orbital hybridization approach to renormalize the disordering spin configuration in porous noble-metal–free metal–organic frameworks (MOFs) to accelerate the spin-dependent reaction kinetics in OER. Herein, we propose an extraordinary super-exchange interaction to reconfigure the domain direction of spin nets at porous MOFs through temporarily bonding with dynamic magnetic ions in electrolytes under alternating electromagnetic field stimulation, in which the spin renormalization from disordering low-spin state to high-spin state facilitates rapid water dissociation and optimal carrier migration, leading to a spin-dependent reaction pathway. Therefore, the spin-renormalized MOFs demonstrate a mass activity of 2,095.1 A gmetal −1 at an overpotential of 0.33 V, which is about 5.9 time of pristine ones. Our findings provide a insight into reconfiguring spin-related catalysts with ordering domain directions to accelerate the oxygen reaction kinetics.

Doping of low-dimensional graphitic materials, including graphene, graphene quantum dots and single-wall carbon nanotubes with nitrogen, sulfur or boron can significantly change their properties. We report that simple fluorination followed by annealing in a dopant source can superdope low-dimensional graphitic materials with a high level of N, S or B. The superdoping results in the following doping levels: (i) for graphene, 29.82, 17.55 and 10.79 at% for N-, S- and B-doping, respectively; (ii) for graphene quantum dots, 36.38 at% for N-doping; and (iii) for single-wall carbon nanotubes, 7.79 and 10.66 at% for N- and S-doping, respectively. As an example, the N-superdoping of graphene can greatly increase the capacitive energy storage, increase the efficiency of the oxygen reduction reaction and induce ferromagnetism. Furthermore, by changing the degree of fluorination, the doping level can be tuned over a wide range, which is important for optimizing the performance of doped low-dimensional graphitic materials. Doping of low-dimensional graphitic materials with heteroatoms can enhance their catalytic, electrochemical and magnetic properties. Here, the authors report a tunable method to ‘superdope’ these materials with high levels of nitrogen, sulfur, or boron, via a simple fluorination and annealing procedure.

Non‐volatile photomemory based on photomodulated luminescent materials offers unique advantages over voltage‐driven memory, including low residual crosstalk and high storage speed. However, conventional materials have thus far been volatile and insecure for data storage because of low trap depth and single‐level storage channels. Therefore, the development of a novel non‐volatile multilevel storage medium for data encryption remains a challenge. Herein, a robust, non‐volatile, multilevel optical storage medium is reported, based on a photomodulated Ba3MgSi2O8:Eu3+, which combined the merits of light‐induced valence (Eu3+ → Eu2+) and photochromic phenomena using optical stimulation effects, accompanied by larger luminescent and color contrasts (>90%). These two unique features provided dual‐level storage channels in a single host, significantly improving the data storage security. Notably, dual‐level optical signals could be written and erased simultaneously by alternating 265 and 365 nm light stimuli. Theoretical calculations indicated that robust color centers induced by intrinsic interstitial Mg and vacancy defects with suitable trap depths enable excellent reversibility and long‐term storage capability. By relying on different luminescent readout mechanisms, the encrypted dual‐level information can be accurately decrypted by separately probing the Eu2+ and Eu3+ signals, thus ensuring information security. This study proposes a novel approach for constructing multilevel information storage channels for information security. Based on unique features of the photomodulated Ba3MgSi2O8:Eu medium: photo‐induced valence (PV) and photochromic (PC) phenomena, a robust, non‐volatile, and multilevel photomemory is successfully designed. The dual‐level storage channels are written and erased simultaneously by alternating 265 and 365 nm stimuli. The encrypted information can be decrypted by separately probing the Eu2+ and Eu3+ signals, thus ensuring information security.

Mn 4+ -activated phosphors have become a hotspot in the development of inorganic red phosphors due to the fascinating photoluminescent properties. Herein, the synergetic manipulation of the flux effect and charge compensation was employed to improve the performance of Mn 4+ -activated CaAl 12 O 19 red phosphors. The crystallinity was improved by appropriate Zn 2+ -doping, while nonradiative transition between Mn 4+ ions is reduced by charge compensation of the formation of Mn 4+ –Mg 2+ pairs with Mg 2+ dopants. Thus, the emission of Mn 4+ -activated CaAl 12 O 19 red phosphors has been remarkably enhanced. The low probability of nonradiative transition between Mn 4+ ions was demonstrated by the thermal stability analysis. To depict the luminescent process, the crystal-field strength ( D q ), and Racah parameters ( B and C ) were calculated to determine the sequence of the energy levels. Meanwhile, the warm WLEDs with high CRI and low CCT were obtained using the prepared phosphors as red-emitting composition. Our results clearly suggested that the synergetic strategy by combining the flux effect and charge compensation is an effective method to enhance the luminescence of CaAl 12 O 19 :Mn 4+ , and CaAl 12 O 19 :Mn 4+ /Zn 2+ /Mg 2+ red-emitting phosphors, which have potential application value in warm WLEDs.

Inducing robust magnetic moments on the basal plane of the graphene sheet is very difficult and is one of the greatest challenges in the study of physical chemistry of graphene materials. Theoretical studies predicted that introduction of a kind of sp 3 -type defects formed by OH groups is an effective pathway to achieve this goal [Boukhvalov, D. W. & Katsnelson, M. I. ACS Nano 5, 2440–2446 (2011)]. Here we demonstrate that OH groups can efficiently induce robust magnetic moments on the basal plane of the graphene sheet. We show that the inducing efficiency can reach as high as 217 μ B per 1000 OH groups. More interestingly, the magnetic moments are robust and can survive even at 900°C. Our findings highlight the importance of OH group as an effective sp 3 -type candidate for inducing robust magnetic moments on the basal plane of the graphene sheet.

To research and develop the potential red emission phosphors for warm white-light-emitting diodes (WLED), we systematically investigated double alkaline rare-earth molybdates KGd 1− x Eu x (MoO 4 ) 2 (0.05 ≤  x  ≤ 1) phosphors. The crystal structure, morphology, chemical composition, and photoluminescence properties of the phosphors with different Eu 3+ doping concentrations were investigated in detail. The results indicate that Eu 3+ doping concentration can affect the crystal structure and morphology of KGd 1− x Eu x (MoO 4 ) 2 phosphors. The luminescence performance reveals that KGd 1− x Eu x (MoO 4 ) 2 phosphor could emit intense red emission under multiplexed excitations at 362, 382, 394, 465, and 535 nm, which are matched well with the commercial UV, blue and green LED chips. An abnormal quenching behavior was observed in the KGd 1− x Eu x (MoO 4 ) 2 phosphors. And the quenching behavior at the excitation of Eu 3+ –O 2− Charge-Transfer band and Eu 3+ ions 4 f –4 f transitions is quite different. Finally, we fabricated a WLED lamp by coating the InGaN blue chip with a mixture of YAG: Ce 3+ yellow phosphors and KEu(MoO 4 ) 2 red phosphors. The obtained WLED lamps showed warm white light with a lower CCT value (~ 5142 K) than that fabricated without the red phosphors (CCT = 5892 K). These results proved that the KGd 1− x Eu x (MoO 4 ) 2 could be a very promising red-emitting phosphor for WLED.

Light-modulated lead-free perovskites-based memristors, combining photoresponse and memory, are promising as multifunctional devices. In this work, lead-free double perovskite Cs2AgBiBr6 films with dense surfaces and uniform grains were prepared by the low-temperature sol-gel method on indium tin oxide (ITO) substrates. A memory device based on a lead-free double perovskite Cs2AgBiBr6 film, Pt/Cs2AgBiBr6/ITO/glass, presents obvious bipolar resistive switching behavior. The ROFF/RON ratio under 445 nm wavelength light illumination is ~100 times greater than that in darkness. A long retention capability (>2400 s) and cycle-to-cycle consistency (>500 times) were observed in this device under light illumination. The resistive switching behavior is primarily attributed to the trap-controlled space-charge-limited current mechanism caused by bromine vacancies in the Cs2AgBiBr6 medium layer. Light modulates resistive states by regulating the condition of photo-generated carriers and changing the Schottky-like barrier of the Pt/Cs2AgBiBr6 interface under bias voltage sweeping.

High-quality CH3NH3PbI 3−xClx (MAPIC) films were prepared using potassium chloride (KCl) as an additive on indium tin oxide (ITO)-coated glass substrates using a simple one-step and low-temperature solution reaction. The Au/KCl-MAPIC/ITO/glass devices exhibited obvious multilevel resistive switching behavior, moderate endurance, and good retention performance. Electrical conduction analysis indicated that the resistive switching behavior of the KCl-doped MAPIC films was primarily attributed to the trap-controlled space-charge-limited current conduction that was caused by the iodine vacancies in the films. Moreover, the modulations of the barrier in the Au/KCl-MAPIC interface under bias voltages were thought to be responsible for the resistive switching in the carrier injection trapping/detrapping process.

A method for gram-scale synthesis of graphitic carbon nitride quantum dots (g-C3N4QDs) was developed. The weight of the g-C3N4QDs was up to 1.32 g in each run with a yield of 66 wt%, and the purity was 99.96 wt%. The results showed that g-C3N4QDs exhibit a stable and strong ultraviolet photoluminescence at a wavelength of 365 nm. More interestingly, the g-C3N4QDs can be used as a high-efficiency, sensitive, and selective fluorescent probe to detect Fe3+ with a detection limit of 0.259 μM.

Reduced graphene oxide–carbon nanotube (RGO–CNT) hybrid materials were prepared by a simple catalyst-free route. The thermostability, photoluminescence (PL) and electrical properties of RGO–CNTs were investigated systematically. The results revealed that compared to RGO, RGO–CNTs showed multicolor PL, and higher thermostability and conductivity. The RGO–CNTs therefore have important potential applications in the fields of photonic and electrical devices.