Intense Pulsed Light-Driven Flash Thermal-Shock Synthesis: A Frontier Strategy for Ultrafast Nanomaterial Design

High Resolution Image Download MS PowerPoint Slide Conspectus Ultrafast annealing represents a paradigm shift in materials synthesis, compressing thermal processing into millisecond-to-subsecond time scales. This approach establishes a unique kinetic-control regime that can enable metastable phases, defect-rich surfaces, engineered interfaces, and atomic-level catalyst functionalization while suppressing thermal degradation that often accompanies conventional furnace-based treatments under equilibrium conditions. Resistive Joule-heating approaches (e.g., carbothermal shock) require conductive supports, whereas laser-based methods often face limitations in uniformity and large-area scalability. Among various ultrafast techniques, light-based approaches offer significant advantages in terms of material compatibility, enabling a broad range of applications. In particular, intense pulsed light (IPL)-driven flash thermal-shock synthesis (FTS) is especially attractive because, unlike general photothermal annealing that typically relies on more moderate optical heating, FTS uses high-intensity broadband xenon-flash pulses to induce a thermal shock within milliseconds. Operating via rapid photothermal conversion, FTS instantaneously achieves ultrahigh temperatures (>2000 K) and rapid heating and cooling rates (10 4 –10 6 K s –1 ). Over the past decade, this flash-processing concept has evolved into a versatile nanomaterials platform capable of converting precursors into functional, often metastable materials under strongly nonequilibrium conditions. In this Account, we first introduce the fundamental photothermal mechanisms and time–temperature characteristics governing FTS. We outline key considerations for material selection─focusing on the strong light-absorption capabilities of carbonaceous materials, defect-engineered metal oxides, and plasmonic metals─alongside the critical metrological challenges of millisecond-scale transient temperature measurement via high-speed infrared pyrometry. We then survey representative nanoengineering strategies enabled by FTS across four major categories. First, atomic-level engineering emphasizes low-thermal-budget heteroatom incorporation (e.g., rapid boron doping into graphene without combustion in ambient air) and the robust stabilization of high-density single-atom catalysts. The ultrafast quenching effectively traps isolated metal atoms at defect sites before diffusion-driven clustering can occur. Second, nanoparticle functionalization covers the transition from monometallic decoration to complex multimetallic and high-entropy alloy (HEA) systems. By leveraging high temperatures to overcome conventional miscibility barriers and rapidly freezing the resulting highly distorted atomic configurations, FTS produces uniformly dispersed HEAs and core(HEA)@shell heterostructures. Third, surface and defect engineering highlight the FTS ability to activate nanomaterial surfaces through rapid reduction, oxygen-vacancy generation, and local modulation of the coordination environment, thereby creating catalytically and electronically active states. Fourth, thermochemical transformations induced by ultrafast photothermal pulses include porosity generation, phase reconstruction, carbothermic synthesis, and heterostructure formation. This also includes transforming nanodiamonds into carbon nanoonions and synthesizing metastable transition metal carbides via carbothermic reactions. Finally, we outline the remaining challenges and future opportunities critical for advancing this field. To guide the rational design of nanomaterials via FTS, we highlight the necessity of expanding the accessible compositional space, developing absorber engineering for nonphotothermal substrates, implementing precise atmosphere programming, and deploying millisecond-resolved in situ and operando analyses to deepen fundamental mechanistic understanding.