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Bridging buried interface enable 24.67%-efficiency doctor-bladed perovskite solar cells in ambient condition

Nano Research 2024年第9期17卷 8068-8076页

作者： Jianhui Chang Erming Feng Xiangxiang Feng Hengyue Li Yang Ding Caoyu Long Siyuan Lu Haixia Zhu Wen Deng Jiayan Shi Yingguo Yang Si Xiao Yongbo Yuan Junliang Yang Hunan Key Laboratory for Super-microstructure and Ultrafast Process School of PhysicsCentral South UniversityChangsha 410083China Hunan Key Laboratory of Nanophotonics and Devices School of PhysicsCentral South UniversityChangsha 410083China Textile and Fashion Collage Hunan Institute of EngineeringXiangtan 411101China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Scalable deposition of high-efficiency perovskite solar cells(PSCs)is critical to accelerating their commercial ***,a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition,exhibiting much negative influence on the efficiency and stability of ***,2-(N-morpholino)ethanesulfonic acid potassium salt(MESK)is incorporated as the bridging layer between the tin oxide(SnO_(2))electron transport layer(ETL)and the perovskite film deposited via scalable two-step doctor *** experiment and simulation results demonstrate that MESK can passivate the trap states of Sn suspension bonds,thereby enhancing the charge extraction and transport of the SnO_(2)***,the strong interaction with uncoordinated Pb ions can modulate the crystal growth and crystallographic orientation of perovskite film and passivate buried *** employing MESK interface bridging,PSCs fabricated via scalable doctor blading in ambient condition achieve a power conversion efficiency(PCE)of 24.67%,which is one of the highest PCEs for doctor-bladed PSCs,and PSC modules with an active area of 11.35 cm^(2)achieve a PCE of 19.45%.Furthermore,PSCs exhibit excellent long-term stability,and the unpackaged target device with a storage of 1680 h in ambient condition(25℃and humidity of 30%relative humidity(RH))can maintain more than 90%of the initial *** research provides a strategy for constructing a high-performance interface bridge between SnO_(2)ETL and perovskite film,and achieving efficient and stable large-area PSCs and modules fabricated via scalable doctor-blading process in ambient condition.

关键词： perovskite solar cells doctor blading buried interface defect passivation orientation regulation

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Janus monolayer TaNF:A new ferrovalley material with large valley splitting and tunable magnetic properties

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Frontiers of physics 2023年第5期18卷 173-181页

作者：郑贵博蘧水仙周文哲欧阳方平 School of Physics and Electronics and Hunan Key Laboratory for Super-Microstructure and Ultrafast Processand Hunan Key Laboratory of Nanophotonics and DevicesCentral South UniversityChangsha 410083China School of Physics and Technology Xinjiang UniversityUrumqi 830046China State Key Laboratory of Powder Metallurgy and Powder Metallurgy Research InstituteCentral South UniversityChangsha 410083China

Materials with large intrinsic valley splitting and high Curie temperature are a huge advantage for studying valleytronics and practical *** this work,using first-principles calculations,a new Janus TaNF monolayer is predicted to exhibit excellent piezoelectric properties and intrinsic valley splitting,resulting from the spontaneous spin polarization,the spatial inversion symmetry breaking and strong spin-orbit coupling(SOC).TaNF is also a potential two-dimensional(2D)magnetic material due to its high Curie temperature and large magnetic anisotropy *** effective control of the band gap of TaNF can be achieved by biaxial strain,which can transform TaNF monolayer from semiconductor to *** magnitude of valley splitting at the CBM can be effectively tuned by biaxial strain due to the changes of orbital composition at the *** magnetic anisotropy energy(MAE)can be manipulated by changing the energy and occupation(unoccupation)states of d orbital compositions through biaxial *** addition,Curie temperature reaches 373 K under only−3%biaxial strain,indicating that Janus TaNF monolayer can be used at high temperatures for spintronic and valleytronic devices.

关键词： Janus valley splitting Curie temperature magnetic anisotropy energy first-principles calculations

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Frustration-enhanced persistent currents in correlated trimer nanorings

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Physical Review B 2025年第8期111卷 L081117-L081117页

作者： Tie-Feng Fang Wei-Tao Lu Ai-Min Guo Qing-Feng Sun School of Physical Science and Technology Nantong University Nantong 226019 China Hunan Key Laboratory for Super-microstructure and Ultrafast Process School of Physics and Electronics Central South University Changsha 410083 China International Center for Quantum Materials School of Physics Peking University Beijing 100871 China Hefei National Laboratory Hefei 230088 China

We investigate the persistent current in a correlated trimer nanoring comprising three magnetic atoms, which sits on a metallic host and encloses a magnetic flux. In the molecular-orbital regime, charge fluctuations can reverse the aromaticity of the trimer molecule by driving quantum phase transitions between many-body states. It is shown that in frustrated trimers the superexchange-induced current as a function of interatom hopping is enhanced by the competition of conflicting magnetic orders, with an asymmetric peak at the quantum criticality separating the ferromagnetic and antiferromagnetic Kondo regimes. Interestingly, the critical current undergoes an anomalous rise with temperature before decaying, signaling the suppression of the Kondo bound state at finite temperature. Our results demonstrate that the coherent current response to external flux indeed conveys important information on the states of strongly correlated systems.

关键词： Nanorings

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Epitaxial quasi-2D/3D hybrid perovskite heterojunctions for photodetector with enhanced detectivity and stability

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Nano Research 2024年第7期17卷 6594-6602页

作者： Yifu Chen Lin Zhang Xinxin Peng Weiran Qin Shiqing Li Yingwei Wang Zhihui Chen Si Xiao Bin Yang Biao Liu Junliang Yang Han Huang Yun Lin Jun He Liming Ding Yongbo Yuan Hunan Key Laboratory of Super Microstructure and Ultrafast Process School of PhysicsCentral South UniversityChangsha 410083China Hunan Key Laboratory of Nanophotonics and Devices School of PhysicsCentral South UniversityChangsha 410083China College of Materials Science and Engineering Hunan UniversityChangsha 410082China Department of Photoelectric Information School of PhysicsCentral South UniversityChangsha 410083China Center for Excellence in Nanoscience Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyChinese Academy of ScienceBeijing 100190China

Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still ***,we report the epitaxial growth of quasi-two-dimensional(Q-2D)perovskites on methylammonium lead iodide(MAPbI_(3))single crystals to form perovskite heterojunctions with interfacial *** MAPbI_(3)adjacent to epitaxial Q-2D perovskite shows blue shifted photoluminescence with shortened lifetime,which becomes significant with the reduced layer number of the Q-2D *** findings suggest the presence of an interfacial strain gradient leading to enhanced photocarrier ***,compared to the MAPbI_(3)single crystal detector,the BA_(2)MAPb_(2)I_(7)/MAPbI_(3)(BA:n-butylamine)heterojunction-based photodetector demonstrates a bandpass detecting property and exhibits 5 times enhanced external quantum efficiency and 83 times enhanced specific detectivity(D*=3.26×10^(11)Jones).Remarkably,the unencapsulated BA_(2)MAPb_(2)I_(7)/MAPbI_(3)heterojunction is stable in ambient condition for>300 *** Q-2D/3D heterojunction shows suppressed ion inter-diffusion due to the presence of Q-2D phase.

关键词： epitaxial growth interfacial strain quasi-two-dimensional/three-dimensional(Q-2D/3D)heterojunctions ion inter-diffusion

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Anisotropic Rabi model with two-photon relaxation

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Physical Review A 2024年第2期110卷 023708-023708页

作者： Hui Li Jia-Kai Shi Li-Bao Fan Zi-Min Li Chuan-Cun Shu Institute of Quantum Physics Hunan Key Laboratory of Nanophotonics and Devices Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics Central South University

The interplay of three light-matter interaction processes, i.e., rotating and counterrotating interactions and two-photon relaxation of the light field, is a topic of interest in quantum optics and quantum information processing. In this work we investigate theoretically the three light-matter interaction processes using the anisotropic Rabi model, which accounts for different strengths of rotating and counterrotating interactions and the unique occurrence of photon escape exclusively in pairs. By numerically solving the Lindblad master equation, we analyze the excitation-relaxation dynamics and derive a non-Hermitian effective Hamiltonian to gain further physical insights. To explore the individual effects of these interactions, we examine three analytically tractable limits of the effective Hamiltonian. Our analysis reveals that the three competitive light-matter interaction processes exhibit sensitivity to parity, leading to intriguing phenomena in both transient and steady states. Particularly interesting dynamical patterns resembling quantum phase transitions emerge when these three interaction terms compete. This work deepens the understanding of ultrastrong light-matter interaction in open quantum systems and offers valuable insights into cavity-based quantum computations.

关键词： Quantum description of light-matter interaction Non-Hermitian systems Rabi model

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General approach for efficient prediction of refrigeration performance in caloric materials

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Physical Review Applied 2024年第1期22卷 014036-014036页

作者： Xiong Xu Weifeng Xie Fangbiao Li Chang Niu Min Li Hui Wang School of Physics Hunan Key Laboratory of Super Microstructure and Ultrafast Process Hunan Key Laboratory of Nanophotonics and Devices State Key Laboratory of Powder Metallurgy Central South University

Solid-state refrigeration holds promise for environmentally friendly cooling with high energy efficiency and downsize scalability. However, its refrigeration performance is notably inferior in comparison with commercial refrigerants due to the lack of scientific guidance for material discovery and performance improvement. Here, we provide an efficient approach to investigate caloric effect under external factors (i.e., electric fields, magnetic fields, and mechanical fields). Using the electrocaloric material PbTiO3 (PTO) as a prototype and employing ab initio calculations combined with deep potential machine learning, we demonstrate the field-dependent isothermal entropy change ΔS and adiabatic temperature change ΔT, along with the coefficient of performance near the phase transitions temperature (Tc). Through analysis of the evolution of microscopic dynamics, we clarify that the refrigeration process involves heat absorption by a transition from a low-potential-energy to a high-potential-energy state. This transition, in a more general case, can be defined as a conventional caloric effect driven by temperature when T > Tc, or an inverse caloric effect driven by external field when T Tc. Importantly, this approach is successfully applied to magnetocaloric, elastocaloric, and barocaloric materials, from which we further showcase the regulation of caloric effect in multicaloric refrigeration process. This work establishes an effective and universal method for predicting key refrigeration parameters, which can be applied to extensive caloric materials, that provide important insights for material design in solid-state cooling technology.

关键词： Elastocaloric effect Electrocaloric effect Magnetocaloric effect Order parameters Solid-state refrigeration Ab initio molecular dynamics Deep learning Density functional calculations

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Effect of halogen on the luminescence properties of two-dimensional double-perovskite (C6H16N2)2AgBiX8⋅H2O (X = Cl,Br and I) with the Dion-Jacobson structure

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Physical Review Applied 2024年第1期22卷 014064-014064页

作者： Jun Luo Biao Liu Jun-Liang Yang Meng-Qiu Cai Hunan Provincial Key Laboratory of High-Energy Scale Physics and Applications School of Physics and Electronics Hunan Key Laboratory for Super-microstructure and Ultrafast Process School of Physics and Electronics Greater Bay Area Institute for Innovation

Two-dimensional (2D) metal halide perovskites have garnered significant attention in the field of light-emitting diodes due to their high photoluminescence quantum yield and tunability. In comparison with the widely studied 2D Ruddlesden-Popper (RP) perovskites, the 2D Dion-Jacobson (DJ) double perovskites, which offer higher stability and nontoxicity, have received relatively less attention. In addition, the regulatory effects of halogens on the luminescence mechanisms and performance of 2D DJ double perovskites remain unknown. Utilizing density functional theory, the stability and luminescence properties of 2D DJ double-perovskite (C6H16N2)2AgBiX8⋅H2O (X = Cl,Br,I) are effectively modulated through halogen substitution. The findings indicate that the dissociation energy incrementally increases as the halogen changes from I to Br to Cl, suggesting that the incorporation of lighter halogens enhances structural stability. The minimal self-trapping formation energy (i.e., 0.08 eV) of (C6H16N2)2AgBiI8⋅H2O facilitates easy detrapment of self-trapped excitons, leading to a tendency toward free exciton luminescence. The self-trapping formation energies of (C6H16N2)2AgBiBr8⋅H2O and (C6H16N2)2AgBiCl8⋅H2O are 0.77 eV and 0.96 eV, respectively, indicating substantial self-trapping depths; thus, favoring self-trapped exciton luminescence. In addition, the transition dipole moments of (C6H16N2)2AgBiBr8⋅H2O and (C6H16N2)2AgBiCl8⋅H2O are substantially higher than those of (C6H16N2)2AgBiI8⋅H2O, suggesting that substituting I with Cl and Br enhances the luminous efficiency of 2D DJ double-perovskite (C6H16N2)2AgBiX8⋅H2O (X = Cl,Br,I). These results indicate that halogen substitution can not only affect the stability of 2D DJ perovskites but also modulate their luminescent properties. Our research provides theoretical insights for the experimental design of superior luminescent materials.

关键词： Luminescence Optoelectronics LEDs Organic-inorganic hybrid perovskites Semiconductor compounds Density functional calculations

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Intrinsically ultralow lattice thermal conductivity and giant thermoelectric effect in Ag-based intercalated layered crystalline solids

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Physical Review B 2024年第23期109卷 235202-235202页

作者： Junpeng Yuan Min Li Hui Wang School of Physics Hunan Key Laboratory of Super Microstructure and Ultrafast Process Hunan Key Laboratory of Nanophotonics and Devices State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China

Understanding the nature of low thermal conductivity and phonon transport properties is critical for the design of potential thermoelectric materials. Based on density-functional theory combined with the phonon Peierls-Boltzmann transport equation, we reveal that Ag-based intercalated layered materials AgBiX2 (X = S, Se, and Te) have inherently low lattice thermal conductivity, which is mainly attributed to the anticrossing behavior of low-frequency optical phonons and longitudinal acoustic phonons induced by the rattling mode of the cations. It is found that the optical phonons in AgBiS2 contribute dominantly (up to 65%) to the total thermal conductivity, originating from the weak bonding nature of intercalated Ag atoms that leads to strong anharmonicity and softening of transverse acoustic phonons. Electronic relaxation times under acoustic deformation potential scattering, polar optical phonon scattering, and ionized impurity scattering are considered to obtain reasonable electron transport properties. The ZT value of p-type AgBiS2 reaches 1.77 for optimal doping at room temperature, which can further be enhanced to ∼2.6 through strain engineering. The present work demonstrates that chemically controlled weak bonding in Ag-based intercalated layered structure produces intrinsically low thermal conductivity and provides important theoretical insight for thermal insulator and thermoelectric applications.

关键词： Anharmonic lattice dynamics Electrical conductivity Electron-phonon coupling Electronic structure Phonons Scattering theory Seebeck effect Thermal conductivity Thermoelectric effects Thermoelectrics 3-dimensional systems Layered crystals Ab initio molecular dynamics Boltzmann theory Density functional calculations Density functional theory First-principles calculations

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Enhanced thermodynamic stability and carrier lifetime in BF4-doped wide-band-gap perovskite solar cells

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Physical Review B 2024年第4期110卷 045142-045142页

作者： Zhong-Yuan Wang Kai-Feng Wang Jun-Jie Jin Fangping Ouyang Biao Meng Zhaofeng Wu Li-Min Liu Chuan-Jia Tong Institute of Quantum Physics Hunan Key Laboratory of Nanophotonics and Devices Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics School of Material Science and Engineering School of Physics

Recent experiments show that doping a small amount of fluorinated pseudohalides (BF4) into CH3NH3PbI3 (MAPbI3) can enhance the performance of wide-band-gap (WBG) perovskite solar cells. Using time-domain density functional theory and ab initio nonadiabatic molecular dynamics we demonstrate that BF4-doped WBG perovskites not only maintain the high defect tolerance but also exhibit greatly improved thermodynamic stability due to enhanced dissociation energy and reduced thermal atomic fluctuation. The strengthened hydrogen bond network introduces increased lattice rigidity, confined inner space, and the reorientated dipole direction of methylammonium molecules, which synergistically suppress the ion migration in BF4-doped MAPbI3 perovskite. Notably, the charge carrier lifetime experiences an order-of-magnitude improvement after BF4 doping, which is mainly attributed to the weakened nonadiabatic coupling. This work provides valuable insights into the effect of fluorinated pseudohalides doped in perovskite materials and suggests a promising approach to enhancing the stability and efficiency of WBG perovskite solar cells.

关键词： Carrier dynamics Electron-phonon coupling Organic-inorganic hybrid perovskites Photovoltaic absorbers Density functional calculations Molecular dynamics

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Giant reversible electrocaloric effect in monolayer group-IV monochalcogenides

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Physical Review B 2024年第6期110卷 064103页

作者： Xiong Xu Min Li X. Lin Hui Wang School of Physics Hunan Key Laboratory of Super Microstructure and Ultrafast Process Hunan Key Laboratory of Nanophotonics and Devices State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China

Monolayer electrocaloric (EC) materials have emerged as promising candidates to achieve economic and green solid-state refrigeration, especially in micro- or nanoscale chip cooling in the post-Moore law period. In this paper, we trained a machine-learning-based deep potential (DP) model of monolayer group-IV monochalcogenides MXs (M = Ge, Sn; X = S, Se) with a database from first-principles calculations, which incorporates the accuracy of ab initio molecular dynamics and efficiency of classical method. The DP model was further applied to study the EC effect (ECE) in monolayer MXs by simulating the temperature-driven phase transitions and electric polarization dynamics under different external electric fields. The results indicate MXs featuring giant reversible isothermal entropy change (ΔS) and adiabatic temperature change (ΔT) near their order-disorder phase transition. Particularly, for E = 100 MV/m, |ΔS| = 68 J/(kg K) and |ΔT| = 75 K are obtained for GeS, which individually rival the state-of-the-art ECE figures of merit, surpassing most other ferroelectric materials, particularly the two-dimensional (2D) CuInPS and strained SrTiO3 films. Furthermore, electric field shifts of the order of 10 MV/m yield huge reversible EC strengths of ΔS/ΔE = 5.4 Jmkg−1K−1MV−1 and ΔT/ΔE = 6 KmMV−1. The origin of the giant ECE in MXs was explained through macroscopic thermodynamic ratios, phenomenological Landau theory, and microscopic phonon vibration analysis. Interestingly, the entropy change can be approximated to be proportional to the square of the polarization change (ΔP2), and the application of electric field shifts the low-frequency phonons to the higher-frequency range, with the M atom contributing more to the entropy change than the X atom. In this paper, we provide important insights for exploration and design of 2D EC materials in future practical applications.

关键词： Electrocaloric effect Entropy Solid-state refrigeration 2-dimensional systems Ferroelectrics Ab initio molecular dynamics Machine learning

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