Transition metal chalcogenide halide (TM–Ch–X) compounds with significant heterogeneity in their chemical bonding have immense potential for thermoelectric applications. Their mixed ionic–covalent bonding nature, combined with intrinsic low lattice symmetry, provides a favorable platform for achieving strong lattice anharmonicity and ultralow lattice thermal conductivity. In this work, we developed a temperature-included crystal graph convolutional neural network to accurately predict mode-resolved Grüneisen parameters, a key descriptor of lattice anharmonicity. Using this approach, two-dimensional NbSe2Br2 is identified as a thermoelectric candidate with strong anharmonicity and ultralow lattice thermal conductivity. First-principles results reveal that the strong anharmonic lattice dynamics originate from its weak and heterogeneous chemical bonding, further leading to ultralow lattice thermal conductivity. NbSe2Br2 also exhibits favorable electronic transport behavior, resulting in a maximum ZT of 1.63. Our work provides a theoretical understanding of the origin of low lattice thermal conductivity in TM–Ch–X compounds with bonding heterogeneity and should encourage further exploration of potential thermoelectric materials.
{"title":"Unveiling bonding heterogeneity-driven anharmonicity and ultralow lattice thermal conductivity in NbSe2Br2: A machine learning accelerated discovery","authors":"Zihan Dong, Yinglin Guan, Minru Wen, Le Huang","doi":"10.1063/5.0304675","DOIUrl":"https://doi.org/10.1063/5.0304675","url":null,"abstract":"Transition metal chalcogenide halide (TM–Ch–X) compounds with significant heterogeneity in their chemical bonding have immense potential for thermoelectric applications. Their mixed ionic–covalent bonding nature, combined with intrinsic low lattice symmetry, provides a favorable platform for achieving strong lattice anharmonicity and ultralow lattice thermal conductivity. In this work, we developed a temperature-included crystal graph convolutional neural network to accurately predict mode-resolved Grüneisen parameters, a key descriptor of lattice anharmonicity. Using this approach, two-dimensional NbSe2Br2 is identified as a thermoelectric candidate with strong anharmonicity and ultralow lattice thermal conductivity. First-principles results reveal that the strong anharmonic lattice dynamics originate from its weak and heterogeneous chemical bonding, further leading to ultralow lattice thermal conductivity. NbSe2Br2 also exhibits favorable electronic transport behavior, resulting in a maximum ZT of 1.63. Our work provides a theoretical understanding of the origin of low lattice thermal conductivity in TM–Ch–X compounds with bonding heterogeneity and should encourage further exploration of potential thermoelectric materials.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"81 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Semimetal molybdenum ditelluride (1T′-MoTe2) possesses diverse phase transitions, enriching its application prospects. The structural response during these transitions is crucial to understanding the underlying mechanisms, but the desired details of pathway and time span are still insufficient. Here, we investigate the lattice evolution in few-layer 1T′-MoTe2 after photoexcitation, using ultrafast electron diffraction and density functional theory (DFT) calculations. The observed complex lattice responses with unintuitively evolving Bragg peak intensity and interplanar spacing are best interpreted as the combination of shear displacement and Mo–Mo bond shortening in a few picoseconds, and a metastable structure in nanoseconds, based on the analyses of structure factor and pair distribution function. The DFT calculations reveal that photodoped electrons induce population change of the antibonding states close to the Fermi level, leading to shear displacement and dimerization of Mo pairs. Our findings present valuable insights for elucidating the picture of Peierls distortion in 1T′-MoTe2.
{"title":"Ultrafast atomic dimerization of Peierls distortion in semimetal molybdenum ditelluride","authors":"Zhong Wang, Chunlong Hu, Changchang Gong, Fuyong Hua, Qian You, Mingkui Wang, Wenxi Liang","doi":"10.1063/5.0289803","DOIUrl":"https://doi.org/10.1063/5.0289803","url":null,"abstract":"Semimetal molybdenum ditelluride (1T′-MoTe2) possesses diverse phase transitions, enriching its application prospects. The structural response during these transitions is crucial to understanding the underlying mechanisms, but the desired details of pathway and time span are still insufficient. Here, we investigate the lattice evolution in few-layer 1T′-MoTe2 after photoexcitation, using ultrafast electron diffraction and density functional theory (DFT) calculations. The observed complex lattice responses with unintuitively evolving Bragg peak intensity and interplanar spacing are best interpreted as the combination of shear displacement and Mo–Mo bond shortening in a few picoseconds, and a metastable structure in nanoseconds, based on the analyses of structure factor and pair distribution function. The DFT calculations reveal that photodoped electrons induce population change of the antibonding states close to the Fermi level, leading to shear displacement and dimerization of Mo pairs. Our findings present valuable insights for elucidating the picture of Peierls distortion in 1T′-MoTe2.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"58 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guangcan Wang, Siying Gao, Yinghui Sun, Zixu Sa, Pengsheng Li, Yanxue Yin, You Meng, SenPo Yip, Zai-xing Yang
The intrinsically weak optical absorption and limited photocarrier separation of atomically thin two-dimensional (2D) materials often limit the photodetector performance. Here, we report an in situ surface growth strategy for preparing a Bi2O2Se/Te heterojunction via a low-temperature chemical vapor deposition method. One-dimensional Te nanowires directly grow on 2D Bi2O2Se nanosheets, forming a clean van der Waals interface and enhancing optical absorption capacity. The Bi2O2Se/Te heterostructure exhibits excellent optoelectronic performance, including an enhanced photocurrent of 1.12 μA, a high responsivity of 50 A/W, and a fast response speed of 32/>168 ms. The enhanced photocurrent and responsivity arise from the efficient electron injection from Te to Bi2O2Se, and hole trapping at the heterointerface. This work demonstrates a non-destructive approach for preparing high-quality heterojunctions and provides an effective pathway for next-generation high-performance near-infrared photodetectors.
原子薄二维材料固有的弱光吸收和有限的光载流子分离往往限制了光电探测器的性能。在这里，我们报告了一种原位表面生长策略，通过低温化学气相沉积方法制备Bi2O2Se/Te异质结。一维Te纳米线直接生长在二维Bi2O2Se纳米片上，形成干净的范德华界面，增强了光吸收能力。Bi2O2Se/Te异质结构具有优异的光电性能，光电流增强1.12 μA，响应率高达50 a /W，响应速度高达32/&；gt；168 ms。Te向Bi2O2Se的有效电子注入和异质界面上的空穴捕获是光电流和响应性增强的主要原因。这项工作展示了一种制备高质量异质结的非破坏性方法，并为下一代高性能近红外光电探测器提供了有效途径。
{"title":"Enhanced photocurrent and responsivity of Bi2O2Se nanosheet near-infrared photodetector by in situ surface growth of Te nanowires","authors":"Guangcan Wang, Siying Gao, Yinghui Sun, Zixu Sa, Pengsheng Li, Yanxue Yin, You Meng, SenPo Yip, Zai-xing Yang","doi":"10.1063/5.0311580","DOIUrl":"https://doi.org/10.1063/5.0311580","url":null,"abstract":"The intrinsically weak optical absorption and limited photocarrier separation of atomically thin two-dimensional (2D) materials often limit the photodetector performance. Here, we report an in situ surface growth strategy for preparing a Bi2O2Se/Te heterojunction via a low-temperature chemical vapor deposition method. One-dimensional Te nanowires directly grow on 2D Bi2O2Se nanosheets, forming a clean van der Waals interface and enhancing optical absorption capacity. The Bi2O2Se/Te heterostructure exhibits excellent optoelectronic performance, including an enhanced photocurrent of 1.12 μA, a high responsivity of 50 A/W, and a fast response speed of 32/>168 ms. The enhanced photocurrent and responsivity arise from the efficient electron injection from Te to Bi2O2Se, and hole trapping at the heterointerface. This work demonstrates a non-destructive approach for preparing high-quality heterojunctions and provides an effective pathway for next-generation high-performance near-infrared photodetectors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"5 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar energy utilization is hindered by intermittency, highlighting the urgency of advanced thermal energy storage technologies. Phase change materials (PCMs) are promising candidates but suffer from leakage and poor photothermal performance. Herein, we fabricate hierarchically porous carbon (PCPC) from petroleum coke (a refinery by-product) via a salt-templating method, which serves as an efficient support for paraffin wax (PW) PCMs. Benefiting from the unique porous structure of PCPC, the resulting form-stable composite PCM (PW/PCPC) exhibits remarkable performance, including a high latent heat of 134.4 J g−1, excellent structural stability, and outstanding cycling durability. Simultaneously, the composite realizes an outstanding photothermal conversion efficiency of 89.68%. A key breakthrough is the development of an integrated solar-thermal-electricity conversion system by combining PW/PCPC with a commercial thermoelectric generator. This system delivers a stable power output density of 7.01 W m−2 and can continuously generate electricity using stored thermal energy even after light source removal. This work not only provides a waste valorization strategy for high-performance composite PCMs but also demonstrates their great potential in efficient solar energy harvesting and sustainable power supply, addressing critical challenges in solar energy utilization.
太阳能的利用受到间歇性的阻碍，突出了先进的热能储存技术的紧迫性。相变材料（PCMs）是一种很有前途的材料，但存在泄漏和光热性能差的问题。在此，我们通过盐模板法从石油焦（一种炼油厂副产品）制备分层多孔碳（PCPC），作为石蜡（PW） PCMs的有效载体。得益于PCPC独特的多孔结构，所制得的形态稳定型复合材料PCM （PW/PCPC）具有134.4 J g−1的高潜热、优异的结构稳定性和出色的循环耐久性。同时，该复合材料光热转换效率高达89.68%。一个关键的突破是通过将PW/PCPC与商用热电发电机相结合，开发出一种集成的太阳能-热电转换系统。该系统提供7.01 W m−2的稳定功率输出密度，即使在光源去除后也可以利用储存的热能连续发电。这项工作不仅为高性能复合pcm提供了一种废物增值策略，而且还展示了它们在高效太阳能收集和可持续供电方面的巨大潜力，解决了太阳能利用中的关键挑战。
{"title":"Petroleum coke-derived porous carbon encapsulating phase change materials for solar-thermal-electricity output","authors":"Jianhua Bian, Lili Wang, Libing Liao, Guocheng Lv","doi":"10.1063/5.0312880","DOIUrl":"https://doi.org/10.1063/5.0312880","url":null,"abstract":"Solar energy utilization is hindered by intermittency, highlighting the urgency of advanced thermal energy storage technologies. Phase change materials (PCMs) are promising candidates but suffer from leakage and poor photothermal performance. Herein, we fabricate hierarchically porous carbon (PCPC) from petroleum coke (a refinery by-product) via a salt-templating method, which serves as an efficient support for paraffin wax (PW) PCMs. Benefiting from the unique porous structure of PCPC, the resulting form-stable composite PCM (PW/PCPC) exhibits remarkable performance, including a high latent heat of 134.4 J g−1, excellent structural stability, and outstanding cycling durability. Simultaneously, the composite realizes an outstanding photothermal conversion efficiency of 89.68%. A key breakthrough is the development of an integrated solar-thermal-electricity conversion system by combining PW/PCPC with a commercial thermoelectric generator. This system delivers a stable power output density of 7.01 W m−2 and can continuously generate electricity using stored thermal energy even after light source removal. This work not only provides a waste valorization strategy for high-performance composite PCMs but also demonstrates their great potential in efficient solar energy harvesting and sustainable power supply, addressing critical challenges in solar energy utilization.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"39 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yueping Wang, Jiayu Li, Huaqiu Du, Cong Liu, Daoyong Cong, Jiajing Yang, Bo Yang, Liang Zuo, Zongbin Li
We report giant elastocaloric effect over a broad temperature window from 90 to 420 K in a Cr-doped directionally solidified (Cu64.5Al24Mn11.5)99.5Cr0.5 cryogenic shape memory alloy with ⟨001⟩A preferred orientation. Even at the temperature down to 90 K, the ΔTad values upon loading and unloading can be as large as 6.9 and −5.6 K, respectively. The combination of giant elastocaloric effect and broad temperature range thus yields a pronounced refrigeration capacity of 4.71 J g−1, well beyond those in the cryogenic elastocaloric materials demonstrated before. Moreover, large ΔTad values higher than 7.3 K remain stable for more than 1200 superelastic cycles at liquefied natural gas temperature (∼110 K) with a low degradation rate (5.8 × 10−4 K/cycle), showing great potential for cryogenic elastocaloric cooling applications.
{"title":"Cryogenic (Cu64.5Al24Mn11.5)99.5Cr0.5 superelastic alloy with broad temperature window of elastocaloric effect","authors":"Yueping Wang, Jiayu Li, Huaqiu Du, Cong Liu, Daoyong Cong, Jiajing Yang, Bo Yang, Liang Zuo, Zongbin Li","doi":"10.1063/5.0313588","DOIUrl":"https://doi.org/10.1063/5.0313588","url":null,"abstract":"We report giant elastocaloric effect over a broad temperature window from 90 to 420 K in a Cr-doped directionally solidified (Cu64.5Al24Mn11.5)99.5Cr0.5 cryogenic shape memory alloy with ⟨001⟩A preferred orientation. Even at the temperature down to 90 K, the ΔTad values upon loading and unloading can be as large as 6.9 and −5.6 K, respectively. The combination of giant elastocaloric effect and broad temperature range thus yields a pronounced refrigeration capacity of 4.71 J g−1, well beyond those in the cryogenic elastocaloric materials demonstrated before. Moreover, large ΔTad values higher than 7.3 K remain stable for more than 1200 superelastic cycles at liquefied natural gas temperature (∼110 K) with a low degradation rate (5.8 × 10−4 K/cycle), showing great potential for cryogenic elastocaloric cooling applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"47 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vertical β-Ga2O3 U-shaped trench structures (UMOSFETs) incorporating current-blocking layers typically suffer from increased on-resistance, primarily caused by deep-level defect states in the trench sidewalls that trap free electrons. In this study, the hydrofluoric acid (HF) sidewall treatment was introduced prior to gate dielectric deposition to modify the trench surface. This process enables the effective incorporation of fluorine atoms into the sidewall region, increasing the electron concentration and mitigating the compensation associated with deep acceptor levels from heavy nitrogen implantation. As a result, the forward conduction is improved. In addition, the HF treatment partially passivates surface and interface traps and provides a mild polishing effect, which slightly reduces surface roughness. These changes help suppress interface scattering and further enhance carrier transport. The fabricated vertical β-Ga2O3 UMOSFETs achieved a specific on-resistance of 6.0 mΩ cm2, a channel mobility of 19.1 cm2/V s, and a breakdown voltage of 1132 V. These results demonstrate that HF sidewall treatment provides a simple and efficient surface engineering approach for significantly enhancing the conduction performance and overall electrical characteristics of β-Ga2O3 UMOSFETs.
{"title":"214 MW/cm2 vertical β -Ga2O3 UMOSFETs enabled by HF sidewall treatment","authors":"Anjing Luo, Gaofu Guo, Zhucheng Li, Zhili Zou, Xuanze Zhou, Tiwei Chen, Li Zhang, Guangwei Xu, Chunhong Zeng, Xiaodong Zhang, Wenhua Shi, Yong Cai, Shibing Long, Zhongming Zeng, Baoshun Zhang","doi":"10.1063/5.0310882","DOIUrl":"https://doi.org/10.1063/5.0310882","url":null,"abstract":"Vertical β-Ga2O3 U-shaped trench structures (UMOSFETs) incorporating current-blocking layers typically suffer from increased on-resistance, primarily caused by deep-level defect states in the trench sidewalls that trap free electrons. In this study, the hydrofluoric acid (HF) sidewall treatment was introduced prior to gate dielectric deposition to modify the trench surface. This process enables the effective incorporation of fluorine atoms into the sidewall region, increasing the electron concentration and mitigating the compensation associated with deep acceptor levels from heavy nitrogen implantation. As a result, the forward conduction is improved. In addition, the HF treatment partially passivates surface and interface traps and provides a mild polishing effect, which slightly reduces surface roughness. These changes help suppress interface scattering and further enhance carrier transport. The fabricated vertical β-Ga2O3 UMOSFETs achieved a specific on-resistance of 6.0 mΩ cm2, a channel mobility of 19.1 cm2/V s, and a breakdown voltage of 1132 V. These results demonstrate that HF sidewall treatment provides a simple and efficient surface engineering approach for significantly enhancing the conduction performance and overall electrical characteristics of β-Ga2O3 UMOSFETs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145961893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mónica G. Simões, Manfred H. Ulz, Bruno B. Ravanello, Kareem Elsayad, Ulrich Hirn, Kristie J. Koski, Caterina Czibula
Hydrogels are three-dimensional networks of hydrophilic polymers that retain large amounts of water and can be tailored for medicine, agriculture, electronics, and cosmetics. Their softness and tunable density complicate contact-based mechanical testing. Here, we explore the mechanics of a cellulose-based hydrogel using Brillouin light scattering (BLS) spectroscopy, a non-contact optical probe. We study micro-fibrillated cellulose hydrogels prepared via two drying routes—a dense, ambient-dried film and a foam-like, freeze-dried aerogel—pre-characterized by tensile testing. BLS is then used to extract longitudinal sound velocity and stiffness in three scattering geometries: reflective backscattering 180a and 90r and transmissive 90a. As expected, the structural arrangement imposed by drying (i.e., material density) dominates the stiffness, resulting in a stiffness of 3 GPa for the aerogel and 19 GPa for the hydrogel film. We further track moisture effects by changing the relative humidity (RH) level (40% RH and 75% RH), which leads to a decrease in frequency shift and a broadening of the Brillouin peaks with increasing RH, and a drop in stiffness by factor two. Time-resolved BLS tracks dehydration kinetics: fully wetting the hydrogel film and merely changing RH produce different Brillouin frequency shift dynamics. These results explore BLS as non-contact method for in situ measurement of mechanical properties during conditioning, with further potential applications during processing of technologically relevant soft and polymeric materials.
{"title":"Probing cellulose hydrogel dehydration with Brillouin spectroscopy: Insights into mechanical properties","authors":"Mónica G. Simões, Manfred H. Ulz, Bruno B. Ravanello, Kareem Elsayad, Ulrich Hirn, Kristie J. Koski, Caterina Czibula","doi":"10.1063/5.0299927","DOIUrl":"https://doi.org/10.1063/5.0299927","url":null,"abstract":"Hydrogels are three-dimensional networks of hydrophilic polymers that retain large amounts of water and can be tailored for medicine, agriculture, electronics, and cosmetics. Their softness and tunable density complicate contact-based mechanical testing. Here, we explore the mechanics of a cellulose-based hydrogel using Brillouin light scattering (BLS) spectroscopy, a non-contact optical probe. We study micro-fibrillated cellulose hydrogels prepared via two drying routes—a dense, ambient-dried film and a foam-like, freeze-dried aerogel—pre-characterized by tensile testing. BLS is then used to extract longitudinal sound velocity and stiffness in three scattering geometries: reflective backscattering 180a and 90r and transmissive 90a. As expected, the structural arrangement imposed by drying (i.e., material density) dominates the stiffness, resulting in a stiffness of 3 GPa for the aerogel and 19 GPa for the hydrogel film. We further track moisture effects by changing the relative humidity (RH) level (40% RH and 75% RH), which leads to a decrease in frequency shift and a broadening of the Brillouin peaks with increasing RH, and a drop in stiffness by factor two. Time-resolved BLS tracks dehydration kinetics: fully wetting the hydrogel film and merely changing RH produce different Brillouin frequency shift dynamics. These results explore BLS as non-contact method for in situ measurement of mechanical properties during conditioning, with further potential applications during processing of technologically relevant soft and polymeric materials.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"36 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145961846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The built-in potential (Vbi) critically governs charge injection and transport in organic and hybrid optoelectronic devices. While self-assembled monolayers (SAMs) are commonly used to tune electrode work functions, whether this tuning directly translates into controllable Vbi remains unresolved due to possible Fermi level pinning. This study systematically investigates how interface pinning influences the energy level landscape and Vbi in poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (poly-TPD) diodes fabricated on SAM-modified NiOx substrates. By tailoring the substrate work function (Φsub) with SAMs, we achieve precise tuning over a wide range (4.3–5.7 eV). Combining electro-modulated absorption spectroscopy, Kelvin probe measurements, and numerical simulations, we find that pinning emerges in poly-TPD when Φsub ≥ 4.7 eV and quantify how Vbi evolves in both pinned and unpinned regimes. The simulations reproduce the observed transition, which is triggered when Φsub exceeds a threshold of approximately 4.9 eV, corresponding to the hole-accepting level in poly-TPD with a state density of ∼2 × 1020 cm−3. Furthermore, both the interfacial potential bending in the pinned state and the polaron signal intensity increase monotonically with Φsub. This work reveals that charge transfer between the substrate and polymer pins Vbi, an insight that provides a mechanistic basis for interface designing in oxide/SAM-based organic electronic devices.
{"title":"Spectroscopic investigation of Fermi level pinning at metal oxide/polymer interfaces and implications for built-in voltage","authors":"Xuerong Zheng, Xiuyuan Lu, Xiaoci Liang, Jinyi Li, Maopeng Xu, Chuan Liu, Jian Lin, Zhiwen Zhou, Wangxiao Jin, Yizheng Jin, Ni Zhao","doi":"10.1063/5.0305224","DOIUrl":"https://doi.org/10.1063/5.0305224","url":null,"abstract":"The built-in potential (Vbi) critically governs charge injection and transport in organic and hybrid optoelectronic devices. While self-assembled monolayers (SAMs) are commonly used to tune electrode work functions, whether this tuning directly translates into controllable Vbi remains unresolved due to possible Fermi level pinning. This study systematically investigates how interface pinning influences the energy level landscape and Vbi in poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (poly-TPD) diodes fabricated on SAM-modified NiOx substrates. By tailoring the substrate work function (Φsub) with SAMs, we achieve precise tuning over a wide range (4.3–5.7 eV). Combining electro-modulated absorption spectroscopy, Kelvin probe measurements, and numerical simulations, we find that pinning emerges in poly-TPD when Φsub ≥ 4.7 eV and quantify how Vbi evolves in both pinned and unpinned regimes. The simulations reproduce the observed transition, which is triggered when Φsub exceeds a threshold of approximately 4.9 eV, corresponding to the hole-accepting level in poly-TPD with a state density of ∼2 × 1020 cm−3. Furthermore, both the interfacial potential bending in the pinned state and the polaron signal intensity increase monotonically with Φsub. This work reveals that charge transfer between the substrate and polymer pins Vbi, an insight that provides a mechanistic basis for interface designing in oxide/SAM-based organic electronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"120 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
, Ayush K Gupta, Aman Khosla, John Rex Mohan, Sourabh Manna, Joseph Vimal Vas, Rajdeep Singh Rawat, Yasuhiro Fukuma, Rohit Medwal
We demonstrate the design of a neuromorphic hardware, spin wave interference device (SWID), utilizing micromagnetic simulations, for performing feature extraction and classification of binary digit patterns. The SWID aims to reduce the weight computations in artificial neural network (ANN) implementations allowing for low power computing and faster inference. We achieve the direct classification of multibit binary input pulse schemes through synaptic behavior and interference of spin waves. We showcase the versatility of SWID's information processing capabilities across two-bit ranges, 4-bit and 6-bit binary digit data, by effectively controlling the nonlinearity and interference of spin waves with external input current pulses. The performance of the SWID with 4-bit and 6-bit digit pattern classification ability is tested for image recognition tasks with the Modified National Institute of Standards and Technology handwritten image database in a feed forward neural network. Though achieving 84.7% accuracy in image recognition, this SWID-based network reduces the weight computation by 99.4% as compared to the software-ANN, showcasing its capability for faster decision making. This huge reduction in computations offers great benefits to ANN applications in edge devices and memory constraint devices. These results underscore the potential of spin wave-based SWID in designing power efficient neuromorphic hardware.
{"title":"Spin wave interference-based efficient neuromorphic computing","authors":", Ayush K Gupta, Aman Khosla, John Rex Mohan, Sourabh Manna, Joseph Vimal Vas, Rajdeep Singh Rawat, Yasuhiro Fukuma, Rohit Medwal","doi":"10.1063/5.0300892","DOIUrl":"https://doi.org/10.1063/5.0300892","url":null,"abstract":"We demonstrate the design of a neuromorphic hardware, spin wave interference device (SWID), utilizing micromagnetic simulations, for performing feature extraction and classification of binary digit patterns. The SWID aims to reduce the weight computations in artificial neural network (ANN) implementations allowing for low power computing and faster inference. We achieve the direct classification of multibit binary input pulse schemes through synaptic behavior and interference of spin waves. We showcase the versatility of SWID's information processing capabilities across two-bit ranges, 4-bit and 6-bit binary digit data, by effectively controlling the nonlinearity and interference of spin waves with external input current pulses. The performance of the SWID with 4-bit and 6-bit digit pattern classification ability is tested for image recognition tasks with the Modified National Institute of Standards and Technology handwritten image database in a feed forward neural network. Though achieving 84.7% accuracy in image recognition, this SWID-based network reduces the weight computation by 99.4% as compared to the software-ANN, showcasing its capability for faster decision making. This huge reduction in computations offers great benefits to ANN applications in edge devices and memory constraint devices. These results underscore the potential of spin wave-based SWID in designing power efficient neuromorphic hardware.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"4 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145961896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunxiao Zhang, Jiaxin Liu, Jiarui Zhang, Yuhao Liu, Hao Hu
The investigation of failure mechanisms in thin-film materials has consistently been a critical aspect of ensuring the reliability of energy storage devices. In this study, full-lifecycle pulsed electrical aging tests were conducted on biaxially oriented polypropylene (BOPP) films. Experimental results reveal that the blisters formed on the surface of electrically aged BOPP films are cavity-structured bubbles, which essentially represent a distinct form of “latent electrical weakness” arising from irreversible material degradation under multi-field electro–thermo–mechanical coupling. Furthermore, a physical model and equivalent impedance were established for these bubbles, providing additional evidence that the blisters play a decisive role in the degradation of the breakdown performance of BOPP films.
{"title":"A weakness breakdown model of a BOPP film based on blister growth under cyclic pulsed voltage","authors":"Yunxiao Zhang, Jiaxin Liu, Jiarui Zhang, Yuhao Liu, Hao Hu","doi":"10.1063/5.0310856","DOIUrl":"https://doi.org/10.1063/5.0310856","url":null,"abstract":"The investigation of failure mechanisms in thin-film materials has consistently been a critical aspect of ensuring the reliability of energy storage devices. In this study, full-lifecycle pulsed electrical aging tests were conducted on biaxially oriented polypropylene (BOPP) films. Experimental results reveal that the blisters formed on the surface of electrically aged BOPP films are cavity-structured bubbles, which essentially represent a distinct form of “latent electrical weakness” arising from irreversible material degradation under multi-field electro–thermo–mechanical coupling. Furthermore, a physical model and equivalent impedance were established for these bubbles, providing additional evidence that the blisters play a decisive role in the degradation of the breakdown performance of BOPP films.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"53 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145961892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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