Improving the diffusion kinetics of sodium ions within TiO2 and its intrinsic electronic conductivity is indispensable to enhance the rate capability and long cyclic stability of TiO2 anodes for ...sodium‐ion batteries. Although single‐heteroatom doping into TiO2 has been widely investigated, a comprehensive understanding of the effects of dual‐heteroatoms doping on the sodium storage performance of TiO2 is still lacking. Herein, nitrogen and sulfur dual‐doping is proposed to achieve a high doping concentration for anatase TiO2 hollow spheres. Experimental data and theoretical calculations reveal that N doping can efficiently narrow the bandgap of TiO2, while S doping is effective in facilitating Na+ diffusion within TiO2. Thus N and S codoped TiO2 shows remarkably boosted electronic conductivity, as well as accelerated sodium ion transfer kinetics owing to the synergistic effect of different doping heteroatoms, which leads to exceptional rate performance (307.5 and 156.4 mAh g−1 at 33.5 and 5025 mA g−1, respectively), and extraordinary cycling stability (90.5% retention over 2400 cycles at 3350 mA g−1). The greatly improved electrochemical performance emphasizes the importance of defects engineering in the rational design of advanced battery materials.
Anatase TiO2 with a high doping concentration is achieved via a nitrogen and sulfur dual‐doping strategy. The synergistic effect of different doping heteroatoms gives rise to highly increased electronic conductivity and accelerated sodium‐ion diffusion kinetics, leading to remarkable rate capability and superior cycling stability. This strategy opens a new avenue to design high‐performance TiO2‐based materials for energy storage systems.
Yb3+ doped lead‐free double perovskites (DPs) with near‐infrared (NIR)‐emitting have attracted extensive attention due to their wide application prospects. Unfortunately, they still suffer from weak ...NIR emission due to undesirable resonance energy transfer between the sensitizers and Yb3+ ions. Herein, a new effective NIR‐emitting DP is developed by co‐doping Sb3+ and Yb3+ into Cs2AgInCl6. Experiments and theoretical calculations reveal that induced by co‐doping Sb3+ ions, the self‐trapped excitation (STE) emission intensity of Cs2AgInCl6 is greatly enhanced by 240 times, and the STE emission shifts from 600 nm to 660 nm, which contributes to a larger spectral overlap between STE emission and the absorption of Yb3+ ions. As a result, the absolute NIR photoluminescence quantum yield reaches an unprecedented 50% in lead‐free DPs via high‐efficiency STE sensitization (>30%). The excellent optical performance of Cs2AgInCl6: Sb, Yb with high ambient, thermal and light stability makes it suitable for application in night‐vision devices. Moreover, an ingenious dual‐modal optical information encryption based on the combination of visible and NIR fluorescence printing patterns utilizing Cs2AgInCl6: Sb and Cs2AgInCl6: Sb, Yb respectively is successfully demonstrated. This study provides inspiration for designing highly efficient NIR‐emitting Ln3+‐doped DPs and illustrates their great potential in versatile optoelectronic applications.
A new design strategy of Sb3+ ions co‐doping in Cs2AgInCl6:Yb3+ is proposed to expand absorption region to longer wavelengths and effectively enhance the near‐infrared emission of Yb3+ ions. The excellent sensitization efficiency from self‐trapped exciton to Yb3+ ions (>30%) gives Sb3+, Yb3+ co‐doped Cs2AgInCl6 unprecedented near‐infrared emission with a photoluminescence quantum yield of up to 50%.
Template‐assistant design and fabrication of porous carbon electrode materials has experienced great progress throughout the past decades and yielded lots of successes via various gas or solid state ...templates. Nevertheless, liquid‐state templates are rather rare in preparing porous carbon materials to date. In this work, melting B2O3 beads are used as both templates and a B dopant, leading to unique B, N co‐doping hierarchically porous carbons containing a “bubble pool”‐like skeleton built of interconnected carbon nanobubbles. Notably, an interesting amending effect of doped B atoms on the N‐doped carbon network can be identified for the first time, which creates a “paddy field”‐like hybrid microstructure with the co‐existence of sp2 short‐range order and sp3 defective areas, leading to an ideal model of carbon materials with both good conductivity and high capacity. Together with the rich ion diffusing pathways and the structural integrity of the “bubble pool”‐like skeleton, the resultant electrode delivers a comprehensive K‐ion storage performance. Therefore, the findings demonstrate the unique pore‐making merits of liquid state templates, which may open the door for exploring porous carbons with more innovations of microstructures and functionalities for applications in energy storage and other fields.
B, N co‐doping porous carbons with “bubble pool”‐like microstructure are readily fabricated via a liquid‐state template strategy. Benefiting from an interesting mending effect of B atoms for N doped carbon networks, the obtained nanobubbles exhibit the co‐existence of good conductivity and high capacity, leading to a comprehensive K‐ions storage ability.
Metallic‐phase selenide molybdenum (1T‐MoSe2) has become a rising star for sodium storage in comparison with its semiconductor phase (2H‐MoSe2) owing to the intrinsic metallic electronic conductivity ...and unimpeded Na+ diffusion structure. However, the thermodynamically unstable nature of 1T phase renders it an unprecedented challenge to realize its phase control and stabilization. Herein, a plasma‐assisted P‐doping‐triggered phase‐transition engineering is proposed to synthesize stabilized P‐doped 1T phase MoSe2 nanoflower composites (P‐1T‐MoSe2 NFs). Mechanism analysis reveals significantly decreased phase‐transition energy barriers of the plasma‐induced Se‐vacancy‐rich MoSe2 from 2H to 1T owing to its low crystallinity and reduced structure stability. The vacancy‐rich structure promotes highly concentrated P doping, which manipulates the electronic structure of the MoSe2 and urges its phase transition, acquiring a high transition efficiency of 91% accompanied with ultrahigh phase stability. As a result, the P‐1T‐MoSe2 NFs deliver an exceptional high reversible capacity of 510.8 mAh g−1 at 50 mA g−1 with no capacity fading over 1000 cycles at 5000 mA g−1 for sodium storage. The underlying mechanism of this phase‐transition engineering verified by profound analysis provides informative guide for designing advanced materials for next‐generation energy‐storage systems.
By adopting a novel plasma‐assisted doping‐triggered phase‐transition engineering, stabilized P‐doped metallic phase selenide molybdenum (MoSe2) nanoflower composites (P‐1T‐MoSe2 NFs) with expanded interlayer spacing, metallic electronic conductivity, facilitated Na+ adsorption, and reduced Na+ diffusion barrier are fabricated for high‐performance sodium storage. The underlying mechanism analysis provides informative guide for designing advanced materials for next‐generation energy‐storage systems.
Smart afterglow materials in response to excitation and delay time, including crystals, polymeric films, and carbon dots, have attracted considerable attention on account of their fundamental value ...in photophysics and promising applications in optoelectronics. However, the fabrication of amorphous and flexible polymer films with fine control remains underexplored. Herein, new doped polymer films based on sodium alginate and aromatic carboxylates are developed, which demonstrate following advantages: (i) easy and fast fabrication through the aqueous solution process, (ii) flexible, transparent, and re‐dissolvable characteristics, (iii) multi‐tunable afterglow colors from blue to red and even white with fine control. Specifically, even better controllability can be achieved through co‐doping and triplet‐to‐singlet Förster resonance energy transfer (TS‐FRET). Multimode advanced anti‐counterfeiting of these materials is demonstrated using their excitation‐ and time‐dependent as well as TS‐FRET‐mediated afterglow colors.
Smart luminescent materials with tunable multicolor afterglows in response to excitation and delay time can be facilely constructed with aqueous processable polymers through physical doping. The afterglow colors can further be finely modulated by the variation of the doping concentration, co‐doping, and the triplet‐to‐singlet Förster resonance energy‐transfer process.
The construction of multi‐heteroatom‐doped metal‐free carbon with a reversibly oxygen‐involving electrocatalytic performance is highly desirable for rechargeable metal‐air batteries. However, the ...conventional approach for doping heteroatoms into the carbon matrix remains a huge challenge owing to multistep postdoping procedures. Here, a self‐templated carbonization strategy to prepare a nitrogen, phosphorus, and fluorine tri‐doped carbon nanosphere (NPF‐CNS) is developed, during which a heteroatom‐enriched covalent triazine polymer serves as a “self‐doping” precursor with C, N, P, and F elements simultaneously, avoiding the tedious and inefficient postdoping procedures. Introducing F enhances the electronic structure and surface wettability of the as‐obtained catalyst, beneficial to improve the electrocatalytic performance. The optimized NPF‐CNS catalyst exhibits a superb electrocatalytic oxygen reduction reaction (ORR) activity, long‐term durability in pH‐universal conditions as well as outstanding oxygen evolution reaction (OER) performance in an alkaline electrolyte. These superior ORR/OER bifunctional electrocatalytic activities are attributed to the predesigned heteroatom catalytic active sites and high specific surface areas of NPF‐CNS. As a demonstration, a zinc‐air battery using the NPF‐CNS cathode displays a high peak power density of 144 mW cm−2 and great stability during 385 discharging/charging cycles, surpassing that of the commercial Pt/C catalyst.
A nitrogen, phosphorus, and fluorine tri‐doped carbon nanosphere (NPF‐CNS) is fabricated from a heteroatom‐enriched covalent triazine polymer by a one‐pot self‐doping strategy. Due to its abundant and uniformly distributed heteroatom electrocatalytic active centers, the as‐developed NPF‐CNS can readily work as an oxygen reduction reaction/oxygen evolution reaction dual‐functional electrocatalyst for a high‐performance rechargeable zinc‐air battery.
The rational design for transition metals‐based carbon nano‐materials as efficient electrocatalysts still remains a crucial challenge for economical electrochemical hydrogen production. Carbon ...nanotubes (CNTs) as attractive electrocatalysts are typically activated by non‐metal dopant to promote catalytic performance. Metals doping or metal/non‐metal co‐doping of CNTs, however, are rarely explored. Herein, this work rationally designs bimetal oxide templates of ZnCo2O4 for heterogeneously doping Zn and N into Co nanoparticles embedded carbon nanotubes (Co@Zn‐N‐CNTs). During the formation of CNTs, Zn atoms volatilize from ZnCo2O4 and in situ dope into the carbon skeleton. In particular, owing to the low electronegativity of Zn, the electrons aptly transfer from Zn to carbon atoms, which generate a high electron density for the carbon layers and offer more preponderant catalytic sites for hydrogen reduction. The Co@Zn‐N‐CNTs catalyst exhibits enhanced hydrogen evolution reaction activity in 0.5 m H2SO4 electrolyte, with a low onset potential of −20 mV versus RHE at 1 mA cm−2, an overpotential of 67 mV at 10 mA cm−2, a small Tafel slope of 52.1 mV dec−1, and persistent long‐term stability. This study provides brand‐new insights into the utilization of Zn as electronic regulator and activity promoter toward the design of high‐efficiency electrocatalysts.
Zn atoms volatilize from ZnCo2O4 and in situ co‐dope with N atoms into the carbon skeleton during the formation of carbon nanotubes (CNTs). The Zn, N co‐doped CNTs have a more controllable morphology and catalytically favorable high Co, N contents, showing better hydrogen evolution reaction activity than 20 wt% Pt/C over 100 mA cm−2.
Exploring highly active and inexpensive bifunctional electrocatalysts for water‐splitting is considered to be one of the prerequisites for developing hydrogen energy technology. Here, an efficient ...simultaneous etching‐doping sedimentation equilibrium (EDSE) strategy is proposed to design and prepare hollow Rh‐doped CoFe‐layered double hydroxides for overall water splitting. The elaborate electrocatalyst with optimized composition and typical hollow structure accelerates the electrochemical reactions, which can achieve a current density of 10 mA cm−2 at an overpotential of 28 mV (600 mA cm−2 at 188 mV) for hydrogen evolution reaction (HER) and 100 mA cm−2 at 245 mV for oxygen evolution reaction (OER). The cell voltage for overall water splitting of the electrolyzer assembled by this electrocatalyst is only 1.46 V, a value far lower than that of commercial electrolyzer constructed by Pt/C and RuO2 and most reported bifunctional electrocatalysts. Furthermore, the existence of Fe vacancies introduced by Rh doping and the typical hollow structure are demonstrated to optimize the entire HER and OER processes. EDSE associates doping with template‐directed hollow structures and paves a new avenue for developing bifunctional electrocatalysts for overall water splitting. It is also believed to be practical in other catalysis fields as well.
Etching‐doping sedimentation equilibrium induces the conversion of zeolitic imidazolate framework‐67 nanotriangles into template‐directed hollow Rh‐doped CoFe‐layered double hydroxides, which can combine the effects of doping and the synthesis method of etching precursor to accelerate the kinetics for water splitting. These findings provide a new avenue for the combination of doping and template‐directed hollow structures.
Controlling the pn‐type behavior of a semiconductor such as silicon by adding an extremely small quantity of an impurity (doping) is a central part of inorganic semiconductor electronics since the ...20th century. Recent progress in the doping of organic semiconductors strongly suggests the advent of a new era of doped organic semiconductors. Here, the principles and effects of doping at the level of parts per million (ppm) in organic semiconductor films and single crystals are described, including descriptions of complete pn‐control, doping sensitization, ppm doping using an extremely low‐speed deposition technique reaching 10−9 nm s−1, and emerging ppm‐level doping effects, such as trap filling, majority carriers, homojunction formation, and decreased mobility, as well as ppm‐level doping effects in organic single crystals measured by the Hall effect, which shows a doping efficiency of 24%. The Wannier excitonic doping of organic single crystals possessing band conduction and the defect science of organic single crystals related to carrier trapping and scattering are introduced as a new scientific field. The dawn of organic single‐crystal electronics is also discussed.
The effects of doping at the parts‐per‐million‐level using an extremely low‐speed deposition technique reaching 10−9 nm s−1 in organic semiconductor films and single crystals are described. These include complete pn‐control, doping sensitization, trap filling, homojunction formation, and high doping efficiency of 24% in organic single crystals measured by the Hall effect. The dawn of organic single‐crystal electronics is discussed.
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