Shape Dependence of Pressure-Induced Phase Transition in CdS Semiconductor Nanocrystals

Compressibility Studies of Copper Selenides Obtained by Cation Exchange Reaction Revealing the New CsCl Phase

In this study, we conducted a high-pressure investigation of Cu2-xSe nanostructures with pyramid- and plate-like morphologies, created through cation exchange from zinc-blende CdSe nanocrystals and wurtzite CdSe nanoplatelets respectively. Using a diamond anvil cell setup at the APS synchrotron, we observed the phase transitions in the Cu2-xSe nanostructures up to 40 GPa, identifying a novel CsCl-type lattice with Pm3̅m symmetry above 4 GPa. This CsCl-type structure, previously unreported in copper selenides, was partially retained after decompression. Our results indicate that the initial crystalline structure of CdSe does not affect the stability of Cu2-xSe nanostructures formed via cation exchange. Both morphologies of Cu2-xSe sintered under compression, potentially contributing to the stabilization of the high-pressure phase through interfacial defects. These findings are significant for discovering new phases with potential applications in future technologies.

Facet-dependent dispersion and aggregation of aqueous hematite nanoparticles

Nanoparticle aggregates in solution controls surface reactivity and function. Complete dispersion often requires additive sorbents to impart a net repulsive interaction between particles. Facet engineering of nanocrystals offers an alternative approach to produce monodisperse suspensions simply based on facet-specific interaction with solvent molecules. Here, we measure the dispersion/aggregation of three morphologies of hematite (α-Fe2O3) nanoparticles in varied aqueous solutions using ex situ electron microscopy and in situ small-angle x-ray scattering. We demonstrate a unique tendency of (104) hematite nanoparticles to maintain a monodisperse state across a wide range of solution conditions not observed with (001)- and (116)-dominated particles. Density functional theory calculations reveal an inert, densely hydrogen-bonded first water layer on the (104) facet that favors interparticle dispersion. Results validate the notion that nanoparticle dispersions can be controlled through morphology for specific solvents, which may help in the development of various nanoparticle applications that rely on their interfacial area to be highly accessible in stable suspensions.

Effects of Pressure on Exciton Absorption and Emission in Strongly Quantum-Confined CsPbBr3 Quantum Dots and Nanoplatelets

Soft lattices of metal halide perovskite (MHP) nanocrystals (NCs) are considered responsible for many of their optical properties associated with excitons, which are often distinct from other semiconductor NCs. Earlier studies of MHP NCs upon compression revealed how structural changes and the resulting changes in the optical properties such as the bandgap can be induced at relatively low pressures. However, the pressure response of the exciton transition itself in MHP NCs remains relatively poorly understood due to limitations inherent to studying weakly or nonconfined NCs in which exciton absorption peaks are not well-separated from the continuum interband transition. Here, we investigated the pressure response of the absorbing and emitting transitions of excitons using strongly quantum-confined CsPbBr3 quantum dots (QDs) and nanoplatelets (NPLs), which both exhibit well-defined exciton absorption peaks. Notably, the reversible vanishing and recovery of the exciton absorption accompanied by reversible quenching and recovery of the emission were observed in both QDs and NPLs, resulting from the reversible pressure modulation of the exciton oscillator strength. Furthermore, CsPbBr3 NPLs exhibited irreversible pressure-induced creation of trap states at low pressures (∼0.1 GPa) responsible for trapped exciton emission that developed on the time scale of ∼10 min, while the reversible pressure response of the absorbing exciton transition was maintained. These findings shed light on the diverse effects the application of force has on the absorbing and emitting exciton transitions in MHP NCs, which are important for their application as excitonic light emitters in high-pressure environments.

Pressure-Modulated Interface Engineering toward Realizing Core@Shell Configuration Transition

The strained interface of core@shell nanocrystals (NCs) can effectively modulate the energy level alignment, thereby significantly affecting the optical properties. Herein, the unique photoluminescence (PL) response of doped Mn ions is introduced as a robust probe to detect the targeted pressure-strain relation of CdS@ZnS NCs. Results show that the core experiences actually less pressure than the applied external pressure, attributed to the pressure-induced optimized interface that reduces the compressive strain on core. The pressure difference between core and shell increases the conduction band and valence band offsets and further achieves the core@shell configuration transition from quasi type II to type I. Accordingly, the PL intensity of CdS@ZnS NCs slightly increases, along with a faster blue-shift rate of PL peak under low pressure. This study elucidates the interplay between external physical pressure and interfacial chemical stress for core@shell NCs, leading to precise construction of interface engineering for practical applications.

Theoretical and Experimental Advances in High-Pressure Behaviors of Nanoparticles

Using compressive mechanical forces, such as pressure, to induce crystallographic phase transitions and mesostructural changes while modulating material properties in nanoparticles (NPs) is a unique way to discover new phase behaviors, create novel nanostructures, and study emerging properties that are difficult to achieve under conventional conditions. In recent decades, NPs of a plethora of chemical compositions, sizes, shapes, surface ligands, and self-assembled mesostructures have been studied under pressure by in-situ scattering and/or spectroscopy techniques. As a result, the fundamental knowledge of pressure-structure-property relationships has been significantly improved, leading to a better understanding of the design guidelines for nanomaterial synthesis. In the present review, we discuss experimental progress in NP high-pressure research conducted primarily over roughly the past four years on semiconductor NPs, metal and metal oxide NPs, and perovskite NPs. We focus on the pressure-induced behaviors of NPs at both the atomic- and mesoscales, inorganic NP property changes upon compression, and the structural and property transitions of perovskite NPs under pressure. We further discuss in depth progress on molecular modeling, including simulations of ligand behavior, phase-change chalcogenides, layered transition metal dichalcogenides, boron nitride, and inorganic and hybrid organic-inorganic perovskites NPs. These models now provide both mechanistic explanations of experimental observations and predictive guidelines for future experimental design. We conclude with a summary and our insights on future directions for exploration of nanomaterial phase transition, coupling, growth, and nanoelectronic and photonic properties.

Pressure-Induced Emission from All-Inorganic Two-Dimensional Vacancy-Ordered Lead-Free Metal Halide Perovskite Nanocrystals

Although seeking an effective strategy for further improving their optical properties is a great challenge, two-dimensional (2D) halide perovskites have attracted a significant amount of attention because of their performance. In this regard, the pressure-induced emission accompanied by a remarkable pressure-enhanced emission is achieved without a phase transition in 2D vacancy-ordered perovskite Cs₃Bi₂Cl₉ nanocrystals (NCs). Note that the initial Cs₃Bi₂Cl₉ NCs possess extremely strong electron-phonon coupling, leading to the easy annihilation of trapped excitons by the phonon. Upon compression, pressure could effectively suppress phonon-assisted nonradiative decay and give rise to an intriguing emission from "0" to "1". Both the weakened electron-phonon coupling and the relaxed halide octahedral distortion benefiting from the vacancy-ordered structure contributed to the subsequent enhanced emission. This work not only elucidates the underlying photophysical mechanism but also identifies pressure engineering as a robust means for improving their potential applications in environmentally friendly solid-state lighting at extremes.

Nanocrystals with metastable high-pressure phases under ambient conditions

The ambient metastability of the rock-salt phase in well-defined model systems comprising nanospheres or nanorods of cadmium selenide, cadmium sulfide, or both was investigated as a function of composition, initial crystal phase, particle structure, shape, surface functionalization, and ordering level of their assemblies. Our experiments show that these nanocrystal systems exhibit ligand-tailorable reversibility in the rock salt-to-zinc blende solid-phase transformation. Interparticle sintering was used to engineer kinetic barriers in the phase transformation to produce ambient-pressure metastable rock-salt structures in a controllable manner. Interconnected nanocrystal networks were identified as an essential structure that hosted metastable high-energy phases at ambient conditions. These findings suggest general rules for transformation-barrier engineering that are useful in the rational design of next-generation materials.

Pressure-stimulus-responsive behaviors of core-shell InP/ZnSe nanocrystals: remarkable piezochromic luminescence and structural assembly

Piezochromic luminescence materials with optical properties can be adjusted (the colors most sensitive to the human eye range from red to green) to provide powerful means for information acquisition in various applications. Inorganic quantum dots, typically based on heavy metals such as cadmium and lead, have congenital advantages as luminescence materials, including strong inoxidizability and excellent photoelectric properties. However, small band-gap shifts under pressure have hindered the development of inorganic-based piezochromic materials. Herein, we combined in situ high-pressure photoluminescence (PL) and absorption measurements with synchrotron X-ray scattering spectra to elucidate the remarkable modulation of optical properties and morphologies by pressure, particularly that of the piezochromic luminescence, in all-inorganic core-shell InP/ZnSe nanocrystals (NCs). We observed a stepwise PL color change from red to green, and an ultrabroad bandgap tunability of 0.46 eV was observed from 1.99 to 2.45 eV in the pressure range of 14.2 GPa for InP/ZnSe NCs. Moreover, two-dimensional (2D) InP/ZnSe nanosheets were synthesized by the stress-driven attachment of nanoparticles. These results demonstrate the ability of the pressure-stimulus response to trigger remarkable piezochromic luminescence and 2D nanosheet assembly in InP/ZnSe NCs, which paves the way for new applications of all-inorganic InP-based semiconductor NCs.

Morphology-Controlled Synthesis of Polyphosphazene-Based Micro- and Nano-Materials and Their Application as Flame Retardants

Common flame retardants, such as halogen-based materials, are being phased-out owing to their harmful environmental and health effects. We prepared poly-(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) microspheres, nanotubes, capsicum-like nanotubes, and branched nanotubes as flame retardants. An increase in reaction temperature changed the morphology from nanotubes to microspheres. A PZS shape had a positive effect on the flame retardancy of polyethylene terephthalate (PET). The PZS with a capsicum-like nanotube morphology had the best flame retardancy, and the PET limiting oxygen index increased from 25.2% to 34.4%. The flame retardancy capability was followed by PZS microspheres (33.1%), branched nanotubes (32.8%), and nanotubes (32.5%). The capsicum-like nanotubes promote the formation of highly dense and continuous carbon layers, and they release a non-combustible gas (CO2). This study confirms polyphosphazene-based flame retardants as viable and environmentally-friendly alternatives to common flame retardants. It also presents a novel and facile design and synthesis of morphology-controlled nanomaterials with enhanced flame retardant properties.

Engineering Near-Infrared Light Emission in Mechanically Exfoliated InSe Platelets through Hydrostatic Pressure for Multicolor Microlasing

γ-indium selenide (InSe) is a van der Waals semiconductor and holds great potentials for low-energy-consumption electronic and optoelectronic devices. Herein, we investigated the hydrostatic pressure engineered near-infrared (NIR) light emission of mechanically exfoliated γ-InSe crystals using the diamond anvil cell (DAC) technique. A record-wide spectral tuning range of 185 nm and a large linear pressure coefficient of 40 nm GPa^-1 were achieved for spontaneous emissions, leading to ultrabroadband microlasing spectrally ranging from 1022 to 911 nm. This high emission tunability can be attributed to the compression of the soft intralayer In-Se bonds under high pressure, which suppressed the band gap shrinkage by increasing the interlayer interaction. Furthermore, two band gap crossovers of valence (direct-to-indirect) and conduction bands were resolved at approximately 4.0 and 7.0 GPa, respectively, resulting in pressure-sensitive emission lifetime and intensity. These findings pave the pathways for pressure-sensitive InSe-based NIR light sources, sensors and so on.

Size and Shape's Effects on the High-Pressure Behavior of WS2 Nanomaterials

Exploring the behavior of nanocrystals with varying shapes and sizes under high pressure is crucial to understanding the relationship between the morphology and properties of nanomaterials. In this study, we investigated the compression behaviors of WS2 nanotubes (NT-WS2) and fullerene-like nanoparticles (IF-WS2) by in situ high-pressure X-ray diffraction (XRD) and Raman spectroscopy. It was found that the bulk modulus of NT-WS2 is 81.7 GPa, which is approximately twice as large as that of IF-WS2 (46.3 GPa). This might be attributed to the fact that IF-WS2 with larger d-spacing along the c-axis and higher defect density are more compressible under isotropic pressure than NT-WS2. Thus, the slender NT-WS2 possess a more stable crystal structure than the IF-WS2. Our findings reveal that the effects of morphology and size play crucial roles in determining the high-pressure properties of WS2 nanoparticles, and provide significant insight into the relationship between structure and properties.

Pressure-Induced Amorphization and Crystallization of Heterophase Pd Nanostructures

Control of structural ordering in noble metals is very important for the exploration of their properties and applications, and thus it is highly desired to have an in-depth understanding of their structural transitions. Herein, through high-pressure treatment, the mutual transformations between crystalline and amorphous phases are achieved in Pd nanosheets (NSs) and nanoparticles (NPs). The amorphous domains in the amorphous/crystalline Pd NSs exhibit pressure-induced crystallization (PIC) phenomenon, which is considered as the preferred structural response of amorphous Pd under high pressure. On the contrary, in the spherical crystalline@amorphous core-shell Pd NPs, pressure-induced amorphization (PIA) is observed in the crystalline core, in which the amorphous-crystalline phase boundary acts as the initiation site for the collapse of crystalline structure. The distinct PIC and PIA phenomena in two different heterophase Pd nanostructures might originate from the different characteristics of Pd NSs and NPs, including morphology, amorphous-crystalline interface, and lattice parameter. This work not only provides insights into the phase transition mechanisms of amorphous/crystalline heterophase noble metal nanostructures, but also offers an alternative route for engineering noble metals with different phases.

In Situ Investigation of the Phase Transition at the Surface of Thermoelectric PbTe with van der Waals Control

The structure of thermoelectric materials largely determines the thermoelectric characteristics. Hence, a better understanding of the details of the structural transformation process/conditions can open doors for new applications. In this study, the structural transformation of PbTe (a typical thermoelectric material) is studied at the atomic scale, and both nucleation and growth are analyzed. We found that the phase transition mainly occurs at the surface of the material, and it is mainly determined by the surface energy and the degree of freedom the atoms have. After exposure to an electron beam and high temperature, high-density crystal-nuclei appear on the surface, which continue to grow into large particles. The particle formation is consistent with the known oriented-attachment growth mode. In addition, the geometric structure changes during the transformation process. The growth of nanoparticles is largely determined by the van der Waals force, due to which adjacent particles gradually move closer. During this movement, as the relative position of the particles changes, the direction of the interaction force changes too, which causes the particles to rotate by a certain angle.

Particle-based hematite crystallization is invariant to initial particle morphology

Many crystallization processes occurring in nature produce highly ordered hierarchical architectures. Their formation cannot be explained using classical models of monomer-by-monomer growth. One of the possible pathways involves crystallization through the attachment of oriented nanocrystals. Thus, it requires detailed understanding of the mechanism of particle dynamics that leads to their precise crystallographic alignment along specific faces. In this study, we discover a particle-morphology–independent oriented attachment mechanism for hematite nanocrystals. Independent of crystal morphology, particles always align along the [001] direction driven by aligning interactions between (001) faces and repulsive interactions between other pairs of hematite faces. These results highlight that strong face specificity along one crystallographic direction can render oriented attachment to be independent of initial particle morphology.

Understanding the mechanism of particle-based crystallization is a formidable problem due to the complexity of macroscopic and interfacial forces driving particle dynamics. The oriented attachment (OA) pathway presents a particularly challenging phenomenon because it occurs only under select conditions and involves a precise crystallographic alignment of particle faces often from distances of several nanometers. Despite the progress made in recent years in understanding the driving forces for particle face selectivity and alignment, questions about the competition between ion-by-ion crystallization, near-surface nucleation, and OA remain. This study examines hydrothermal conditions leading to apparent OA for hematite using three initial particle morphologies with various exposed faces. All three particle types formed single-crystal or twinned one-dimensional (1D) chain-like structures along the [001] direction driven by the attractive interactions between (001) faces and repulsive interactions between other pairs of hematite faces. Moreover, simulations of the potential of mean force for iron species and scanning transmission electron microscopy (S/TEM) imaging confirm that the formation of 1D chains is a result of the attachment of independently nucleated particles and does not follow the near-surface nucleation or ion-by-ion crystallization pathways. These results highlight that strong face specificity along one crystallographic direction can render OA to be independent of initial particle morphology.

The Effect of Particle Size and Composition on the Optical and Electronic Properties of CdO and CdS Rocksalt Nanoparticles

Quantum confinement like behaviour in CdO and CdS nanoparticles is demonstrated through explicit evGW-BSE many-body perturbation theory calculations on 0.6-1.4 nanometre particles of these materials. However, while the lowest optical...

Self-trapped exciton emission and piezochromism in conventional 3D lead bromide perovskite nanocrystals under high pressure

Developing single-component materials with bright-white emission is required for energy-saving applications. Self-trapped exciton (STE) emission is regarded as a robust way to generate intrinsic white light in halide perovskites. However, STE emission usually occurs in low-dimensional perovskites whereby a lower level of structural connectivity reduces the conductivity. Enabling conventional three-dimensional (3D) perovskites to produce STEs to elicit competitive white emission is challenging. Here, we first achieved STEs-related emission of white light with outstanding chromaticity coordinates of (0.330, 0.325) in typical 3D perovskites, Mn-doped CsPbBr3 nanocrystals (NCs), through pressure processing. Remarkable piezochromism from red to blue was also realized in compressed Mn-doped CsPbBr3 NCs. Doping engineering by size-mismatched Mn dopants could give rise to the formation of localized carriers. Hence, high pressure could further induce octahedra distortion to accommodate the STEs, which has never occurred in pure 3D perovskites. Our study not only offers deep insights into the photophysical nature of perovskites, it also provides a promising strategy towards high-quality, stable white-light emission.

Pressure-Driven Reverse Intersystem Crossing: New Path toward Bright Deep-Blue Emission of Lead-Free Halide Double Perovskites

Maximizing the regeneration of singlet excitons remains a considerable challenge in deep-blue emission systems to obtain low-cost, high-efficiency fluorescent materials. However, the formation of the long-lifetime triplet excitons generally dominates the radiative process, making it greatly difficult to harvest deep-blue emission with high color purity because of the depression of singlet excitons. Here, a very bright deep-blue emission in double perovskite Cs₂Na_0.4Ag_0.6InCl₆ alloyed with Bi doping (CNAICB) was successfully achieved by pressure-driven reverse intersystem crossing (RISC), an abnormal photophysical process of energy transfer from the excited triplet state back to the singlet. Therein, the inherently broad emission of CNAICB was associated with the self-trapped excitons (STEs) at excited triplet states, whereas the radiative recombination of STEs populated in excited singlet states was responsible for the observed deep-blue emission. Moreover, the deep-blue emission corresponds to Commission Internationale de L'Eclairage (CIE) coordinates (0.16, 0.06) at 5.01 GPa, which meets the requirement of Rec. 2020 display standards. Likewise, pressure was introduced as an efficient tool to rule out the possibility of the recombination of free excitons and clarify the long-standing conventional dispute over the origin of the low-wavelength emission of Cs₂AgInCl₆. Our study not only demonstrates that pressure can be a robust means to boost the deep-blue emission but also provides deep insights into the structure-property relationship of lead-free CNAICB double perovskites.

Harvesting Cool Daylight in Hybrid Organic-Inorganic Halides Microtubules through the Reservation of Pressure-Induced Emission

Pressure-induced emission (PIE) is extensively studied in halide perovskites or derivative hybrid halides. However, owing to the soft inorganic lattice of these materials, the intense emission is barely retained under ambient conditions, thus largely limiting their practical applications in optoelectronics at atmospheric pressure. Here, remarkably enhanced emission in microtubules of the 0D hybrid halide (C₅ H₇ N₂ )₂ ZnBr₄ ((4AMP)₂ ZnBr₄ ) is successfully achieved by means of pressure treatment at room temperature. Notably, the emission, which is over ten times more intense than the emission in the initial state, is retained under ambient conditions upon the complete release of pressure. Furthermore, the pressure processing enables the tuning of "sky blue light" before compression to "cool daylight" with a remarkable quantum yield of 88.52% after decompression, which is of considerable interest for applications in next-generation lighting and displays. The irreversible electronic structural transition, induced by the steric hindrance with respect to complexly configurational organic molecules [4AMP], is highly responsible for the eventual retention of PIE and tuning of the color temperature. The findings represent a significant step toward the capture of PIE under ambient conditions, thus facilitating its potential solid-state lighting applications.

New-phase retention in colloidal core/shell nanocrystals via pressure-modulated phase engineering

Core/shell nanocrystals (NCs) integrate collaborative functionalization that would trigger advanced properties, such as high energy conversion efficiency, nonblinking emission, and spin-orbit coupling. Such prospects are highly correlated with the crystal structure of individual constituents. However, it is challenging to achieve novel phases in core/shell NCs, generally non-existing in bulk counterparts. Here, we present a fast and clean high-pressure approach to fabricate heterostructured core/shell MnSe/MnS NCs with a new phase that does not occur in their bulk counterparts. We determine the new phase as an orthorhombic MnP structure (B31 phase), with close-packed zigzagged arrangements within unit cells. Encapsulation of the solid MnSe nanorod with an MnS shell allows us to identify two separate phase transitions with recognizable diffraction patterns under high pressure, where the heterointerface effect regulates the wurtzite → rocksalt → B31 phase transitions of the core. First-principles calculations indicate that the B31 phase is thermodynamically stable under high pressure and can survive under ambient conditions owing to the synergistic effect of subtle enthalpy differences and large surface energy in nanomaterials. The ability to retain the new phase may open up the opportunity for future manipulation of electronic and magnetic properties in heterostructured nanostructures.

Pressure-Induced Emission toward Harvesting Cold White Light from Warm White Light

The pressure-induced emission (PIE) behavior of halide perovskites has attracted widespread attention and has potential application in pressure sensing. However, high-pressure reversibility largely inhibits practical applications. Here, we describe the emission enhancement and non-doping control of the color temperature in two-dimensional perovskite (C₆ H₅ CH₂ CH₂ NH₃ )₂ PbCl₄ ((PEA)₂ PbCl₄ ) nanocrystals (NCs) through high-pressure processing. A remarkable 5 times PIE was achieved at a mild pressure of 0.4 GPa, which was highly associated with the enhanced radiative recombination of self-trapped excitons. Of particular importance is the retention of the 1.6 times emission of dense (PEA)₂ PbCl₄ NCs upon the complete release of pressure, accompanied by a color change from "warm" (4403 K) to "cold" white light with 14295 K. The irreversible pressure-induced structural amorphization, which facilitates the remaining local distortion of inorganic Pb-Cl octahedra with respect to the steric hindrance of organic PEA⁺ cations, should be greatly responsible for the quenched high-efficiency photoluminescence.

Size and morphology effects on the high pressure behaviors of Mn3O4 nanorods

The high-pressure behaviors of Mn3O4 nanorods were studied by high pressure powder synchrotron X-ray diffraction and Raman spectroscopy. We found that the initial hausmannite phase transforms into the orthorhombic CaTi2O4-type structure, and then to the marokite-like phase upon compression. Upon decompression, the marokite-like phase is retained at the ambient pressure. Compared with Mn3O4 bulk and nanoparticles, Mn3O4 nanorods show obviously different phase transition behaviors. Upon compression, the phase transition sequence of Mn3O4 nanorods is similar with the nanoparticles, while the decompression behavior is consistent with the bulk counterparts. The hausmannite phase shows higher stability and smaller bulk modulus in Mn3O4 nanorods than those of the corresponding bulk and nanoparticles. We proposed that the higher phase stability and compressibility of the nanorods are concerned with their nanosize effects and the rod morphology. Both the growth orientation and the suppressed Jahn-Teller distortion of the Mn3O4 nanorods are crucial factors for their high pressure behaviors.

Nanoscale Encapsulation of Perovskite Nanocrystal Luminescent Films via Plasma-Enhanced SiO2 Atomic Layer Deposition

Photoluminescence perovskite nanocrystals (NCs) have shown significant potential in optoelectronic applications in view of their narrow band emission with high photoluminescence quantum yields and color tunability. The main obstacle for practical applications is to obtain high durability against an external environment. In this work, a low temperature (50 °C) plasma-enhanced atomic layer deposition (PE-ALD) protection strategy was developed to stabilize CsPbBr₃ NCs. Silica was employed as the encapsulation layer because of its excellent light transmission performance and water corrosion resistance. The growth mechanism of inorganic SiO₂ via PE-ALD was investigated in detail. The Si precursor bis(diethylamino)silane (BDEAS) reacted with the hydroxyl groups (-OH) and thereby initiated the subsequent silica growth while having minimal influence to the organic ligands and did not cause PL quenching. Subsequently, O₂ plasma with high reactivity was used to oxidize the amine ligands of the BDEAS precursor while did not etch the NCs. The obtained CsPbBr₃ NCs/SiO₂ film exhibited exceptional stability in water, light, and heat as compared to the pristine NC film. Based on this method, a white light-emitting diode with improved operational stability was successfully fabricated, which exhibited a wide color gamut (∼126% of the National Television Standard Committee). Our work successfully demonstrates an efficient protection scheme via the PE-ALD method, which extends the applied range of other materials for stabilization of perovskite NCs through this approach.