Oxidation Of Tin Research Articles

Metastable Oxygen-Induced Light-Enhanced Doping in Mixed Sn-Pb Halide Perovskites.

Mixed Sn-Pb halide perovskites are promising absorber materials for solar cells due to the possibility of tuning the bandgap energy down to 1.2-1.3 eV. However, tin-containing perovskites are susceptible to oxidation affecting the optoelectronic properties. In this work, we investigated qualitatively and quantitatively metastable oxygen-induced doping in isolated ASnxPb1-xI3 (where A is methylammonium or a mixture of formamidinium and cesium) perovskite thin films by means of microwave conductivity, structural and optical characterization techniques. We observe that longer oxygen exposure times lead to progressively higher dark conductivities, which slowly decay back to their original levels over days. Here oxygen acts as an electron acceptor, leading to tin oxidation from Sn2+ to Sn4+ and creation of free holes. The metastable oxygen-induced doping is enhanced by exposing the perovskite simultaneously to oxygen and light. Next, we show that doping not only leads to the reduction in the photoconductivity signal but also induces long-term effects even after loss of doping, which is thought to derive from consecutive oxidation reactions leading to the formation of defect states. On prolonged exposure to oxygen and light, optical and structural changes can be observed and related to the formation of SnOx and loss of iodide near the surface. Our work highlights that even a short-term exposure to oxygen immediately impairs the charge carrier dynamics of the perovskite, while structural perovskite degradation is only noticeable upon long-term exposure and accumulation of oxidation products. Hence, for efficient solar cells, exposure of mixed Sn-Pb perovskites to oxygen during production and operation should be rigorously blocked.

Alder-Ene Reaction-Mediated Suppression of Tin(II) Oxidation for Efficient Tin-Lead Perovskite Solar Cells.

Despite numerous studies have reported the inhibition of tin (II) oxidation in mixed tin-lead halide perovskite, there remains a dearth of mechanistic information regarding how tin (II) undergoes oxidation in the precursor solution, particularly in terms of the involvement of DMSO. We here take advantage of density functional theory (DFT) to uncover that SnI2 can coordinate with DMSO and react with singlet oxygen, resulting in the generation of Sn (IV). Moreover, our DFT simulations reveal that benzaldehyde oxime (BZHO) competes with SnI2 in reacting with oxygen through the Alder-ene reaction, hence effectively restraining the oxidation of tin (II), which is further verified by several experimental characterizations. Besides, the introduction of BZHO has also regulated the crystallization of the perovskite film and modified the electronic structure of the perovskite surface. As a result, the perovskite solar cells with the addition of BZHO demonstrate superior performance and operational stability, retaining 82 % of the initial PCE under continuous 1-sun illumination for 800 hours. Furthermore, the efficiency of all-perovskite tandem solar cells treated with BZHO reached 26.76 %. Therefore, this work presents a promising strategy for designing high-performance and stable all-perovskite tandem solar cells.

Alder‐Ene Reaction‐Mediated Suppression of Tin(II) Oxidation for Efficient Tin‐Lead Perovskite Solar Cells

AbstractDespite numerous studies have reported the inhibition of tin (II) oxidation in mixed tin‐lead halide perovskite, there remains a dearth of mechanistic information regarding how tin (II) undergoes oxidation in the precursor solution, particularly in terms of the involvement of DMSO. We here take advantage of density functional theory (DFT) to uncover that SnI2 can coordinate with DMSO and react with singlet oxygen, resulting in the generation of Sn (IV). Moreover, our DFT simulations reveal that benzaldehyde oxime (BZHO) competes with SnI2 in reacting with oxygen through the Alder‐ene reaction, hence effectively restraining the oxidation of tin (II), which is further verified by several experimental characterizations. Besides, the introduction of BZHO has also regulated the crystallization of the perovskite film and modified the electronic structure of the perovskite surface. As a result, the perovskite solar cells with the addition of BZHO demonstrate superior performance and operational stability, retaining 82 % of the initial PCE under continuous 1‐sun illumination for 800 hours. Furthermore, the efficiency of all‐perovskite tandem solar cells treated with BZHO reached 26.76 %. Therefore, this work presents a promising strategy for designing high‐performance and stable all‐perovskite tandem solar cells.

Stabilization of Sn2+ in FA0.75MA0.25SnI3 perovskite thin films using an electron donor polymer, PCDTBT, and an improvement in the charge transport properties of perovskite solar cells

Lead-free tin halide perovskites for the fabrication of perovskite solar cells have attracted considerable attention due to their outstanding optoelectronic and ecofriendly properties. These materials face severe issues, such as poor environmental stability, low formation energy and faster oxidation of tin from the Sn2+ to Sn4+ state, leading to poor film quality and self-doping. In this work, we have fabricated FA0.75MA0.25SnI3 perovskite thin films via a solution processing method and studied the conjugated polymer poly [N-9′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadia-zole)] (PCDTBT)-induced effects in perovskite thin films. The micro-strain of PCDTBT-doped FA0.75MA0.25SnI3 perovskite reduced without any change in the crystal structure. Reductions in electron trap density have been observed due to improved film quality and enlarged perovskite grains. We have observed that the Sn4+ content in 0.050 wt% PCDTBT-doped FA0.75MA0.25SnI3 perovskite film gets reduced, as shown in the x-ray photoelectron spectroscopy (XPS) results. The reduction in Sn4+ (cause of self-doping) content shows that PCDTBT doping maintains the stability of Sn2+ in FA0.75MA0.25SnI3 perovskite thin film. A decrement in hole density from 3.2 × 1018 cm−3 for pristine films to 1.3 × 1017cm−3 for 0.050 wt% PCDTBT-doped FA0.75MA0.25SnI3 perovskite has been observed from C–V measurement, which is consistent with the XPS results. Thus, PCDTBT doping in perovskite films can effectively tackle the severe issues of tin oxidation and defects in the lead-free tin halide perovskite photoactive layer for solar cell application.

Tin Halide Perovskite Epitaxial Films on Gold Surfaces: Atomic Structure and Stability

AbstractTin‐based halide perovskite solar cells can be efficient and environmentally friendly substitutions to lead‐based halide perovskite solar cells, but they have a drawback due to oxidation from Sn2+ to Sn4+. Using vacuum deposition, epitaxially aligned CsSnBr3 ultrathin films are prepared on Au(111) and Au(100) and characterized with scanning tunneling microscopy (STM), low‐energy electron diffraction (LEED), and X‐ray photoelectron spectroscopy (XPS). By co‐evaporation of the precursor molecules CsBr and SnBr2, few monolayers of perovskite are obtained. On Au(111), CsSnBr3 grows in three differently oriented domains due to the hexagonal symmetry of the substrate. On Au(100), which has square symmetry, identical to CsSnBr3, but with about half the lattice constant of the perovskite, a (2×2) superstructure is observed. The perovskite is terminated with the (001) facet showing a square surface structure in agreement with density functional theory (DFT) calculations. Chemical analysis is performed in ultra‐high vacuum (UHV) conditions and no indication of a tin oxidation state higher than Sn2+ is found in the films. However, after exposure to air, rapid and severe changes in the films are observed, highlighting the importance of preparing tin perovskites in a controlled environment to maintain their stability and avoid oxidation‐related issues.

Optical properties of two-dimensional tin nanosheets epitaxially grown on graphene

Heterostacks formed by combining two-dimensional materials show novel properties which are of great interest for new applications in electronics, photonics and even twistronics, the new emerging field born after the outstanding discoveries on twisted graphene. Here, we report the direct growth of tin nanosheets at the two-dimensional limit via molecular beam epitaxy on chemical vapor deposited graphene on Al2O3(0001). The mutual interaction between the tin nanosheets and graphene is evidenced by structural and chemical investigations. On the one hand, Raman spectroscopy indicates that graphene undergoes compressive strain after the tin growth, while no charge transfer is observed. On the other hand, chemical analysis shows that tin nanosheets interaction with sapphire is mediated by graphene avoiding the tin oxidation occurring in the direct growth on this substrate. Remarkably, optical measurements show that the absorption of tin nanosheets exhibits a graphene-like behavior with a strong absorption in the ultraviolet photon energy range, therein resulting in a different optical response compared to tin nanosheets on bare sapphire. The optical properties of ultra-thin tin films therefore represent an open and flexible playground for the absorption of light in a broad range of the electromagnetic spectrum and technologically relevant applications for photon harvesting and sensors.

Polymer Lewis Base for Improving the Charge Transfer in Tin-Lead Mixed Perovskite Solar Cells.

The poor film stability of Sn-Pb mixed perovskite film and the mismatched interface energy levels pose significant challenges in enhancing the efficiency of tin-lead (Sn-Pb) mixed perovskite solar cells. In this study, polyvinylpyrrolidone (PVP) is introduced into the PVK perovskite precursor solution, effectively enhancing the overall stability of the film. This improvement is achieved through the formation of robust coordination bonds between the carbonyl (C=O) in the pyrrole ring and the undercoordinated SnII and PbII, thereby facilitating the passivation of defects. Furthermore, the introduction of PVP inhibits the oxidation of tin (Sn), thereby enhancing the n-type characteristics of the perovskite film. This adjustment in the energy level of the PVK perovskite film proves instrumental in reducing interface energy loss, subsequently improving interface charge transfer and mitigating device recombination. Consequently, perovskite solar cells incorporating PVP achieve an outstanding champion power conversion efficiency (PCE) of 21.31%.

Reducing Hole Trap Density in Sn–Pb Perovskite Solar Cells via Molecular Phenylhydrazine

Narrow‐bandgap Sn–Pb‐alloyed perovskite is potential for a bottom cell in perovskite tandem solar cells. However, Sn‐contained perovskites tend to be readily oxidized in air atmosphere, which has ill influence on stability and photovoltaic performance. Herein, a method to suppress oxidation of divalent tin via post‐treatment of perovskite film with phenylhydrazine is reported. Phenylhydrazine‐treated FA0.5MA0.5Pb0.5Sn0.5I3 perovskite films effectively reduce the hole traps caused by the oxidation of Sn2+ on the perovskite surfaces. In addition, surface energetics are well aligned by post‐treatment, which is beneficial for voltage gain and charge transport. As a result, power conversion efficiency (PCE) is increased from 18.16% to 20.67% after post‐treatment due mainly to the significant improvement of open‐circuit voltage from 0.75 to 0.83 V. Furthermore, the device stability is improved, where 91.67% of initial PCE is maintained after 1000 h.

Structure-stability correlations in terms of microstructure during tin oxidation as examined by in situ high-temperature X-ray powder diffraction

Structure-stability correlations in terms of microstructure during tin oxidation as examined by in situ high-temperature X-ray powder diffraction

Charting the Irreversible Degradation Modes of Low Bandgap Pb‐Sn Perovskite Compositions for De‐Risking Practical Industrial Development

AbstractThe commercialization of a solar technology necessitates the fulfillment of specific requirements both regarding efficiency and stability to enter and gain space in the photovoltaic market. These aims are heavily dependent on the selection of suitable materials, which is critical for suppressing any reliability risks arising from inherent instabilities. Focusing on the absorber material, herein the most suitable low bandgap lead‐tin composition candidate for all‐perovskite tandem applications is investigated by studying their degradation mechanisms with both widely available and advanced characterization techniques. Three irreversible degradation processes are identified in narrow bandgap Pb‐Sn perovskite absorbers: 1) Tin (Sn) oxidation upon air exposure, 2) methylammonium (MA) loss upon heat exposure, and 3) formamidinium (FA) and cesium (Cs) segregation leading to impurity phase formation. From an industrial perspective, it is proposed to refocus attention on FASn0.5Pb0.5I3 which minimizes all three effects while maintaining a suitable bandgap for a bottom cell and good performance. Moreover, a practical and highly sensitive characterization method is proposed to monitor the oxidation, which can be deployed both in laboratory and industrial environments and provide useful information for the technological development process, including, the effectiveness of encapsulation methods, and the acceptable time windows for air exposure.

First-principles study of F adsorption by TiN with its oxide surface in three-dimensional NAND flash memory

Three-dimensional (3D) NAND flash memory is a key technology in the field of mainstream memory solutions, which is primarily due to its extremely low bit cost. The architecture of 3D NAND, characterized by its vertically stacked design, substantially enhances the capacity of individual chips. This advancement is completely consistent with the demands for high-capacity data storage in contemporary environments, securing its widespread adoption in diverse application scenarios. As storage density increases, the complexity of process integration increases, bringing new challenges. The word lines in 3D NAND are typically filled by using gate replacement techniques, and compared with chemical vapor deposition (CVD), atomic layer deposition (ALD) is favored for its superior step-coverage, especially for depositing tungsten (W) at the gate. However, due to the complexity of the replacement gate deposition structure, fluorine (F) residues are found in the voids of the tungsten metal gate filling structure and diffuse into the surrounding structure under subsequent process conditions, corroding other films such as silicon oxide and degrading device performance and reliability. To alleviate the problem of fluorine attack, a thin layer of titanium nitride is usually deposited as a barrier layer before deposition of tungsten gate, which blocks the fluorine in the tungsten gate and prevents its diffusion into the oxide layer. Previously, there were studies to increase the ability to stop F diffusion by varying the thickness of the F blocking layer (TiN). However, increasing the thickness of TiN will further increase the complexity of high aspect ratio etching in the 3D NAND process, which will have adverse effect on subsequent processes. To further minimize the effect of fluorine erosion, residual fluorine elements can be removed by introducing annealing in the subsequent process flow. In the actual 3D NAND process, elemental fluorine (F) is adsorbed and accumulates on the TiN surface, and is further activated by subsequent high-temperature processes, leading to severe fluorine erosion. The delay between TiN deposition and subsequent processing steps is hypothesized to facilitate fluorine adsorption due to the oxidation of TiN. This work corroborates this hypothesis through first-principles calculations, and demonstrates the role of TiN oxidation in fluorine adsorption. In this work, we evaluate the effect of this oxidation on the fluorine-blocking effectiveness of the TiN barrier layer. We simulate the adsorption of fluorine-containing by-products on TiN and its oxides, providing theoretical insights into mitigating fluorine attack. The higher degree of oxidation of TiN is more likely to cause F adsorption, and Ti exposed surface TiN is more prone to oxidation, which is more likely to cause F adsorption in unoxidized condition and oxidized condition. Based on these insights, we implemente an ammonia purge treatment in 3D NAND manufacturing, which effectively minimizes fluorine attack, reducing the leakage probability of word line by 25% and wafer warpage by 43%.

Characterization of Nanostructured Tin Oxide Anodes Obtained By Electrolytic Oxidation for High-Energy Lithium-Ion Batteries

In recent years, the growing electric vehicle market has increased the need for cost efficient and high energy materials for batteries drastically. Tin and tin oxide materials bear great potential as anode materials for Li-Ion batteries due to low cost and high theoretical capacity. Nevertheless, the development of commercial tin anodes has so far been hindered due to several drawbacks related to high volume expansion during operation leading to fast cell degradation. To circumvent these issues, nanostructured electrodes can be applied to mitigate volume changes. Typically, the production process of such electrodes is challenging, leading to high cost and issues in terms of scalability. Electrochemical processes, such as the electrolytic oxidation of tin, has been found a promising alternative to fabricate nanostructured electrodes. The additive-free tin oxide anodes obtained from this process exhibit high gravimetric and volumetric capacity, excellent rate capability as well as promising cycle life. The morphology and microstructure have high impact on the rate capability and cycling stability of tin oxide anodes. Since structural properties can be precisely adjusted by controlling the electrochemical oxidation process, a deeper understanding of the structure-property relationship is needed to optimize the production process and pave the way for commercialization.Herein an in-depth characterization of nanostructured tin oxide anodes formed by electrochemical oxidation is presented. The rate capability and the cycling stability are investigated by means of electrochemical measurements in battery cells. Operando electrochemical dilatometry is used to investigate the thickness change of the anodes during cycling (cell breathing). In-situ XRD measurements are applied to elucidate the reaction mechanism. The anodes are carefully analyzed by SEM/EDS at different state of lithiation to understand the impact of volume changes on the inner porosity and morphology. Finally, the cycling stability of tin oxide anodes is improved by applying an electrochemical prelithiation step. Therefore, the impact of different prelithiation regimes on the cycling stability is evaluated in full cells. The results contribute to the understanding of electrochemical behavior of nanostructured tin oxide anodes and the derivation of optimal design criteria adjusted by electrochemical surface engineering.

Effective of l-tyrosine hydrochloride on the photovoltaic performance of tin-based perovskite solar cells by suppressing tin (II) oxidation

Additive engineering has been widely concerned to improve the photovoltaic performance of tin-based perovskite solar cells (PSCs). Here, the tin-based perovskite precursor solution is modified with L-Tyrosine hydrochloride (LTHCl). The results demonstrate that the defect state density of tin-based perovskite films is reduced by improving their morphology and crystallinity. The electrical properties of tin-based perovskite film are enhanced by suppressing the Sn2+ oxidation. As a result, the open-circuit voltage of tin-based PSCs is increased from 0.53 V to 0.59 V. The best power conversion efficiency of the tin-based PSC with LTHCl is up to 8.63 %, which is higher than that of the pristine device (7.65 %). Meanwhile, the tin-based PSC with LTHCl retains 84 % of its initial efficiency after over 1140 h in a nitrogen glove box.

Corrosion Behaviors of Artificial Chloride Patina for Studying Bronze Sculpture Corrosion in Marine Environments

Copper trihydroxychlorides, which are known as “bronze disease”, are dangerous corrosion products that compromise the stability and conservation of bronze sculptures. Here, we performed artificial patina corrosion experiments on quaternary bronze (Cu-Zn-Sn-Pb) to examine the corrosion behavior of the chloride patina commonly found in bronze objects in marine environments. The chromaticity and reflectance of the patina in the context of the corrosion products indicate that copper trihydroxychloride, which is commonly found in a single color in marine environments, was produced early in the corrosion experiment. Furthermore, the corrosion of bronze had different effects on the alloying elements, contrary to pure copper corrosion. The chloride patina formed a single patina layer of copper trihydroxychlorides. This patina layer was divided into the outer porous powder and inner uniform layers. Furthermore, the interaction of oxygen in the atmosphere with the corrosion layer and internal oxidation of tin in the alloy promoted powdering. These results provide important basic data for research on sculpture conservation and corrosion characteristics, such as changes in color, chemical composition, and corrosion products on the patina surfaces of outdoor bronze sculptures.

Design of an Ultra-Wideband Transparent Wave Absorber.

In this paper, a multilayer ultra-wideband transparent metamaterial wave absorber is proposed, which has the characteristics of ultra-wideband wave absorption, light transmission and flexible bending; in addition, due to the complete symmetry of the structure, the absorber has polarization insensitivity to incident electromagnetic waves. Both simulation and experimental results show that the frequency range of the microwave absorption rate is higher than 90% between 8.7 GHz and 38.9 GHz (between which most of the absorption rate can reach more than 95%), the total bandwidth is 30.2 GHz, and the relative bandwidth is 126.9%, realizing microwave broadband absorption and covering commonly used communication frequency bands such as X-band, Ku-band, and K-band. A sample was processed and tested. The test results are in good agreement with the results of the theoretical analysis, which proves the correctness of the theoretical analysis. In addition, through the selection and oxidation of indium tin (ITO) materials, the metamaterial also has the characteristics of optical transparency and flexibility, so it has potential application value in the window radar stealth and conformal radar stealth of weapons and equipment.

Urea additive improves the performance of low bandgap tin–lead perovskite solar cells

Recently, narrow bandgap tin–lead mixed perovskite solar cells (PSCs) have become a research hotspot because they can be applied in tandem cells to break the Shockley–Queisser radiative limit of the single junction PSCs. However, the introduction of tin, on the one hand, makes the crystal quality of perovskite thin film worse, leading to the increase of film defects; on the other hand, the easy oxidation of divalent tin also leads to the increase of defect states, which seriously affects the photoelectric conversion efficiency of tin–lead cell devices. Good crystallization and low defect density of perovskite layer are very important to ensure good light absorption and photogenerated carrier generation and transport. Here, we adjust the crystallization of tin–lead perovskite films by a Lewis base—urea (CO(NH2)2), which significantly increases the grain size and improves the film morphology. At the same time, because of the Lewis base property of urea, the uncoordinated Pb2+ and Sn2+ defects of Lewis acids in the tin–lead films are effectively passivated, and the occurrence of non-radiative recombination in the films is reduced. Under the dual effects of improving crystallization and passivating defects, the photoelectric performance of tin–lead perovskite solar cell devices is significantly improved to 18.1% compared with the original device of 15.4%.

Fabrication of Z-Type TiN@(A,R)TiO2 Plasmonic Photocatalyst with Enhanced Photocatalytic Activity.

Plasmonic effect-enhanced Z-type heterojunction photocatalysts comprise a promising solution to the two fundamental problems of current TiO2-based photocatalysis concerning low-charge carrier separation efficiency and low utilization of solar illumination. A plasmonic effect-enhanced TiN@anatase-TiO2/rutile-TiO2 Z-type heterojunction photocatalyst with the strong interface of the N-O chemical bond was synthesized by hydrothermal oxidation of TiN. The prepared photocatalyst shows desirable visible light absorption and good visible-light-photocatalytic activity. The enhancement in photocatalytic activities contribute to the plasma resonance effect of TiN, the N-O bond-connected charge transfer channel at the TiO2/TiN heterointerface, and the synergistically Z-type charge transfer pathway between the anatase TiO2 (A-TiO2) and rutile TiO2 (R-TiO2). The optimization study shows that the catalyst with a weight ratio of A-TiO2/R-TiO2/TiN of approximately 15:1:1 achieved the best visible light photodegradation activity. This work demonstrates the effectiveness of fabricating plasmonic effect-enhanced Z-type heterostructure semiconductor photocatalysts with enhanced visible-light-photocatalytic activities.

The performances and structure evolution of Pt-based catalysts for selective hydrogen combustion under propene-rich conditions

In the present study, the kinetic behaviour and active sites evolution processes of Pt-based catalysts were investigated. It was found that highly selective hydrogen combustion could be achieved over Sn modified Pt-based catalysts in presence of both propane and propene (over 98%). The stability tests, kinetic study and catalyst characterization revealed that the existence of oxygenated species is the reason for accelerated coking reactions. The formation of graphitized cokes serving as additional unselective active sites and the oxidation of tin in PtSn alloy phases are the primary reasons causing the catalytic selectivity loss during long-run tests under propene-rich condition.

Influence of SWCNT on the Electrical Behavior of an Environmentally Friendly CH3NH3SnI3 Perovskite-Based Optoelectronic Schottky Device

The lead-free tin-based halide perovskite CH3NH3SnI3 has recently been explored in a wide range of optoelectronic device applications. However, the charge conduction process of the CH3NH3SnI3 perovskite layer is hindered by the presence of vacancies resulting from tin oxidation, sample defects, and trap states, which limit the performance of the device. In this study, we introduced single-walled carbon nanotubes (SWCNTs) into the perovskite to enhance the charge conduction of the device. To demonstrate this, CH3NH3SnI3 perovskite and its composites with SWCNTs were synthesized and used as an active layer in a sandwich-structured device. Electrical measurements show that the device based on SWCNTs exhibits superior performance compared to the device consisting solely of perovskite. Incorporating SWCNTs into the device improves conductivity and reduces series resistance. Specifically, in the absence of light, SWCNTs increase the conductivity from 3.8 × 10–5 to 1.6 × 10–4 S/m and decrease the series resistance from 348.25 to 34.80 Ω. Under illumination, SWCNTs further increase conductivity to 4.0 × 10–4 S/m from 8.1 × 10–5 S/m and decrease series resistance to 19.20 Ω from 220.56 Ω. The results suggest that SWCNT can serve as a channel for charge extraction. An analysis of space charge limited current (SCLC) conduction indicates that incorporating SWCNT decreases the trap energy from 103.22 to 79.70 meV under dark conditions. This implies that SWCNT also acts as a filler for trap states. Based on these findings, it appears that the SWCNT-CH3NH3SnI3 perovskite composite has the potential to yield high-performance optoelectronic devices. This study presents an intriguing approach for enhancing carrier transfer with minimal recombination loss and could serve as a source of inspiration for future research in the optoelectronics field.

Insights into size-dependent oxidation pathways in TiN: Atomic phase transformation and structural failure

TiN, as a classic ceramic material, has been widely used in a variety of practical applications due to its unique physical and inert chemical properties. The oxidation behavior of TiN is detrimental to both its engineering and functional applications. However, the intuitive recognition of the oxidation mechanism and corresponding structural failure is ambiguous so far. This work reports the oxidation pathways of TiN with different grain sizes via careful atomic structure characterization. Nano-sized TiN single crystal undergoes a two-step phase transformation, i.e. anatase and subsequently rutile TiO2, whereas micron-sized TiN single crystal or polycrystals directly convert to rutile TiO2 upon oxidation. Notably, numerous N2 nanobubbles generate in the micron-sized TiN oxidation process, which preferentially embedded inside of rutile TiO2 grain boundaries for single crystal and the oxide/nitride interface for polycrystals. The atomic structure of a nanobubble edge indicates it is generally epitaxial bonding with {101} and {200} of rutile TiO2. Besides, the oxidation induces great volume expansion in all types of TiN, but only micron-sized single crystals are fractured and pulverized dramatically, accompanying with rationally impairing the mechanical properties. The fundamental exploration of oxidation behavior at atomic scale would help to guide rational structural/phase design of advanced ceramic materials.