Although microscopic techniques have been used to characterize transition metal dichalcogenides (TMDs), direct observation of charge carrier dynamics distribution in TMDs with diverse shapes remains unexplored. Herein, ultrafast pump–probe microscopy (UPPM) is employed to reveal the carrier dynamics distribution in molybdenum disulfide (MoS2) and tungsten disulfide (WS2) monolayer of four shapes: triangular (t‐MoS2), curved triangular (c‐MoS2), triangular (t‐WS2), and hexagonal (h‐WS2). Monitoring the photon transmission T at 1.55 eV after pumping with a photon energy of 3.1 eV, a negative ΔT/T occurs in t‐MoS2 and c‐MoS2, while a positive ΔT/T is detected in t‐WS2 and h‐WS2 after 3–7 ps time evolution. This distinctive behavior is attributed to deep/shallow defects below the conduction band minimum (CBM) in MoS2 and WS2. Spatial‐independent ΔT/T is observed in t‐MoS2 and t‐WS2, while the ΔT/T in c‐MoS2 has a rapid decay of photoexcited carriers at the vertices and curved edges. Additionally, a threefold symmetry of ΔT/T is revealed in h‐WS2, attributed to the dissimilar occupation of defect states near the h‐WS2 CBM. This work paves the way for examining charge carrier dynamics of various shapes of TMDs and provides a unique microscopic method for studying the charge carrier dynamics in emerging TMDs heterostructures.

Nanoscale metallic glasses offer opportunities for investigating fundamental properties of amorphous solids and technological applications in biomedicine, microengineering, and catalysis. However, the top-down fabrication of metallic glass nanostructure is restricted by the availability of bulk metallic glass; in contrast, the bottom-up synthesis remains rarely explored due to the rigorous formation conditions, especially the extreme cooling rate. Here we develop a kinetically controlled flash carbothermic reaction, featuring ultrafast heating and cooling rates, for the synthesis of metallic glass nanoparticles within milliseconds. Ten permutations of noble metals, base metals, and metalloid (M1-M2-P, M1 = Pt/Pd, M2 = Cu/Ni/Fe/Co/Sn) were synthesized with widely tunable particle sizes and supportive substrates. Through combinatorial development, we discovered a substantially expanded phase space for metallic glass at the nanoscale than that at the bulk scale, revealing an enhanced glass forming ability due to the nanosize effect. Leveraging this effect, we synthesized several nanoscale metallic glasses with elemental compositions that have never, to our knowledge, been synthesized in bulk. The metallic glass nanoparticles show high intrinsic activity in electrocatalysis and heterogeneous catalysis, outperforming crystalline nanoparticle counterparts and commercial precious metal nanoparticle benchmarks.