Temperature-Dependent Two-Dimensional Transition Metal Dichalcogenide Heterostructures: Controlled Synthesis and Their Properties

Vertically stacked and laterally stitched heterostructures consisting of two-dimensional (2D) transition metal dichalcogenides (TMDCs) are predicted to possess novel electronic and optical properties, which offer opportunities for the development of next-generation electronic and optoelectronic devices. In the present work, we report the temperature-dependent synthesis of 2D TMDC heterostructures on Si/SiO₂ substrates, including MoS₂–WS₂, WS₂–MoS₂–WS₂, Mo_1–<i>x</i>W_<i>x</i>S₂–WS₂, and Mo_1–<i>x</i>W_<i>x</i>S₂ alloyed bilayer heterostructures by ambient pressure chemical vapor deposition (CVD). Raman and photoluminescence mapping studies demonstrate that the as-produced heterostructures show distinct structural and optical modulation. Our results indicate that the evolution of various 2D heterostructures originates from the competition between the adsorption and desorption of Mo atoms and the diffusion of W atoms under various growth temperatures. This work sheds light on the design and fabrication of heterostructures using controllable interfaces and junctions of diverse TMDC atomic layers

Amplifying Photon Upconversion in Alloyed Nanoparticles for a Near-Infrared Photodetector

Photon upconverison has attracted a substantial amount of interest in diverse fields due to its characteristic anti-Stokes emissions. However, obtaining intense emission under low-power laser irradiation has remained a challenge. Here we report a mechanistic design of activator–sensitizer alloyed nanoparticles to achieve bright upconversion under weak infrared irradiation. This design allows a nearest sensitizer–activator separation to facilitate efficient energy transfer that results in remarkably enhanced upconversion (>2 orders of magnitude) under 0.26 W cm–2 irradiation compared to that of the Er sublattice, and the upconversion quantum yield also shows a 20-fold increase. Interestingly, the alloyed nanoparticles exhibit a gradual change in emission color with an increase in Yb3+ content, and moreover, their emission colors can be dynamically controlled by simply modulating the excitation laser power and pulse widths. Such alloyed nanoparticles show great promise for application in a near-infrared photodetector

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Machine-Learning-Driven Discovery of Mn⁴⁺-Doped Red-Emitting Fluorides with Short Excited-State Lifetime and High Efficiency for Mini Light-Emitting Diode Displays

The discovery of high-efficiency Mn4+-activated fluoride red phosphors with short excited-state lifetimes (ESLs) is urgent and crucial for high-quality, wide-color-gamut display applications. However, it is still a great challenge to design target phosphors with both short ESL and high luminescence efficiency. Herein, we propose an efficient machine learning approach based on a small dataset to establish the ESL prediction model, thereby facilitating the discovery of new Mn4+-activated fluorides with short ESLs. Such a model can not only accurately predict the ESLs of Mn4+ in fluorides but also quantify the impact of structure features on ESLs, therefore elucidating the “structure-lifetime” correlations. Guided by the correlations, two new Mn4+-doped tetramethylammonium (TMA)-based hybrid fluorides (TMA)2BF6:Mn4+ (B = Sn or Hf) with both short ESLs (τ ≤ 3.7 ms) and high quantum efficiencies (internal QEs > 92%, external QEs > 55%) have been discovered successfully. A prototype displayer with excellent performance (∼124% National Television Standards Committee (NTSC) color gamut) is assembled by employing a (TMA)2SnF6:Mn4+-based white Mini-LED backlight module, demonstrating its practical prospects in high-quality displays. This work not only brings promising candidates for Mn4+-doped fluoride phosphors but also provides a valuable reference for accelerating the discovery of new promising phosphors

Highly Efficient and Thermally Stable K₃AlF₆:Mn⁴⁺ as a Red Phosphor for Ultra-High-Performance Warm White Light-Emitting Diodes

Following pioneering work, solution-processable Mn⁴⁺-activated fluoride pigments, such as A₂BF₆ (A = Na, K, Rb, Cs; A₂ = Ba, Zn; B = Si, Ge, Ti, Zr, Sn), have attracted considerable attention as highly promising red phosphors for warm white light-emitting diodes (W-LEDs). To date, these fluoride pigments have been synthesized via traditional chemical routes with HF solution. However, in addition to the possible dangers of hypertoxic HF, the uncontrolled precipitation of fluorides and the extensive processing steps produce large morphological variations, resulting in a wide variation in the LED performance of the resulting devices, which hampers their prospects for practical applications. Here, we demonstrate a prototype W-LED with K₃AlF₆:Mn⁴⁺ as the red light component via an efficient and water-processable cation-exchange green route. The prototype already shows an efficient luminous efficacy (LE) beyond 190 lm/W, along with an excellent color rendering index (Ra = 84) and a lower correlated color temperature (CCT = 3665 K). We find that the Mn⁴⁺ ions at the distorted octahedral sites in K₃AlF₆:Mn⁴⁺ can produce a high photoluminescence thermal and color stability, and higher quantum efficiency (QE) (internal QE (IQE) of 88% and external QE (EQE) of 50.6%.) that are in turn responsible for the realization of a high LE by the warm W-LEDs. Our findings indicate that the water-processed K₃AlF₆ may be a highly suitable candidate for fabricating high-performance warm W-LEDs