INORGANIC CHEMISTRY
·
2018
·
IF 4.7
Chunyan Jiang,Mingying Peng,Alok M. Srivastava,Lihua Li,Mikhail G. Brik
Narrow band red-emitting Mn4+-doped fluoride phosphor is an essential red component of modern white-light-emitting-diode (WLED) devices. Its luminescence has sensitivity to structure and influences the performance of WLED. In this paper, we report a high-performance Mn4+ phosphor based on a new heterodialkaline fluorogermanate, CsNaGeF6:Mn4+. As determined by the single-crystal X-ray diffraction analysis, the CsNaGeF6 compound crystallizes in the orthorhombic crystal system with space group Pbcm (No. 57). Under excitation by 360 and 470 nm photons, CsNaGeF6:Mn4+ emits intense red light near 630 nm with a high quantum yield of 95.6%. The electronic energy levels of the Mn4+ ion in Cs2GeF6, Na2GeF6, and CsNaGeF6 are calculated using the exchange charge model of crystal-field theory. The local Mn4+ environment inducing different zero-phonon-line emissions in the structures is probed by electron paramagnetic resonance. The Mn4+-doped heterodialkaline fluorogermanate CsNaGeF6:Mn4+ exhibits broader emission as a result of the lowest symmetry. It has higher quantum yield than Na2GeF6:Mn4+ and higher spectral luminous efficacy than Cs2GeF6:Mn4+. Given the good thermal stability and efficient luminescence, a prototype warm-WLED device with a color rendering index of 92.5, a correlated color temperature of 3783 K, and a luminous efficacy of 176.3 lm/W has been fabricated by employing the CsNaGeF6:Mn4+ phosphor as the red component. Our results not only reveal that a high-performance Mn4+ red phosphor is achieved through cationic substitutions but also construct a relationship of performance–structure to guide the design of Mn4+ phosphors in the future.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Energy Materials
·
2022
·Vol. 12
·期 10
·2103690
·
IF 29.698
Fanqi Meng,Bingcheng Yu,Qinghua Zhang,Yuqi Cui,Shan Tan,Jiangjian Shi,Lin Gu,Dongmei Li,Qingbo Meng,Cewen Nan
Aiming at stable CsPbI 3 perovskite solar cells, Ge incorporated for the first time into DMAPbI 3 -based precursor systems. Ge incorporation is found to be able to modify crystallization growth of CsPb 1− x Ge x I 3 films and reduce annealing temperature and treatment time by lowering CsPbI 3 formation energy. The champion power conversion efficiency (PCE) of 19.52% is achieved with a certified PCE of 18.8%, which is the highest performance of CsPbI 3 PSCs with alien element-doping. In addition, in situ formation of GeO 2 can passivate the grain boundary and surface defects, thus significantly improving the moisture resistance of the perovskite film and related devices. Excellent operational stability is achieved with no PCE degradation over 3000 h at a fixed bias voltage of 0.85 V under continuous white LED (6500 K) illumination and a nitrogen atmosphere. This work demonstrates that Ge-incorporation is a promising way to stabilize CsPbI 3 perovskite solar cells by simultaneously improving perovskite crystallinity and passivating the grain boundary and interfacial defects.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2022
·Vol. 32
·期 39
·2204687
·
IF 19.924
Chunhui Wang,Dong Wang,Xin Ma,Haozhe Qin,Mingkai Liu,Yan Yan,Bao Zhang,Xing Ou
High-performance conversion-reaction-based electrodes have received enormous attention due to their high theoretical capacities, yet the poor structural stability and large stress accumulation induced from volume change are identified as major limiting factors for further utilization. Although viable strategies are exerted to acquire durable storage capacity, the controllable technology of inner stress is still required to explore. Herein, the amorphous structured GeS 2 with 2D porous sheet morphology is designed for sodium-ion batteries (SIBs). The differences in reaction mechanism and structure reversibility between amorphous and crystalline states are systematically investigated and unraveled. Notably, the amorphous matrix can ensure evenly distributed intermediate interface and alleviated aggregation of active materials, promoting the complete conversion reaction with decreased hysteresis. Furthermore, it provides more isotropic Na-ion diffusion channels and active sites, effectively boosting the reaction kinetics. Meanwhile, it can fully relieve the volume expansion and restrain the inner stress of GeS 2 , resulting in excellent structural tolerance. As expected, it expresses prominent rate capability and cyclic life (512.8 mA h g −1 at a superhigh rate of 10 A g −1 after 1000 cycles) for SIBs. Therefore, amorphization engineering is a reliable strategy to obtain the robust framework and unimpeded diffusion channels for developing high-performance conversion-reaction-based electrode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2022
·Vol. 6
·期 19
·4520-4527
·
IF 6.813
Jian Hao,Jun Bai,Jing Wang,Lu Xu,Junli Guo,Caixia Chi,Haihong Li
The large volume changes of Ge-based electrode result in poor electrochemical cycling and rate performance and are the important factors hampering the practical implementation of Ge-based materials in Li-ion batteries (LIBs). Here we fabricated a fascicular structure Ge/Zn2GeO4 (Ge/Zn2GeO4NFs) by an in situ growth of flower-like Zn2GeO4 on micron-sized Ge. In an EDTA/water solvent system, Zn2GeO4 were generated on the Ge substrate, and self-assembled into a flower-like structure through coordination and H-bonding. Benefiting from the improved structural stability and abundant transmission channels of lithium ions and electrons, the as-fabricated Ge/Zn2GeO4NFs anodes exhibited excellent cyclability and rate performance. At a current density of 0.2 A g−1, Ge/Zn2GeO4NFs delivered a high capacity of 1621 mA h g−1 with an initial coulombic efficiency of 62%, and even after the 200th cycle a capacity of 816 mA h g−1 could be maintained. Further, the Ge/Zn2GeO4NFs anode delivered excellent rate capabilities of 567 and 388 mA h g−1 at high current densities of 2 and 5 A g−1, which were superior to the micron-sized Ge electrode (133 mA h g−1 at 5 A g−1). The results show that the Zn2GeO4 nanoflower, which adheres on the micron Ge substrate inseparably, could buffer the volume change of Ge, enlarge the electrolyte contact area, provide continuous lithium-ion and electron pathways, and thus improve the lithium-storage performance of the micron-sized Ge electrodes. This synthesis strategy provides new ideas for the development of micron-sized anode materials for LIBs.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Tianbiao Zeng,Dong Feng,Qimeng Peng,Qi Liu,Guocui Xi,Gang Chen
Among the germanium-based compounds, GeTe is a promising anode candidate that exhibits high theoretical capacity (856 mAh g–1 vs Li+/Li and 401 mAh g–1 vs Na+/Na) and low volume expansion during an ion intercalation/deintercalation process. Nevertheless, achieving good dispersion of metal-like GeTe in anode materials remains a significant challenge. Herein, hybrid GeTe/graphene (GeTe/G) is proposed as a highly efficient anode for LiBs and SiBs by facile ball milling. Pulverized GeTe is effectively anchored on peeled graphene sheets that can accelerate Li+ transport in electrodes as predicted by theoretical calculations and thus result in improved overall electrochemical performance. For instance, GeTe/G possesses a high reversible capacity of 478 mAh g–1 under 0.1 A g–1 in the 300th cycle. Moreover, by further cross-linking the GeTe/G using carbon nanotube (CNT) and carbon nanofiber pyrolysis from cotton cellulose, the as-prepared three-dimensional (3D) flexible anode possesses macropores that acted as positive channels favorably for ion transport. Remarkably, the as-prepared flexible 3D GeTe/G/CNT electrode with a thickness of 1050 μm exhibits a high reversible capacity of 451.4 mAh g–1 (4.38 mAh cm–2) vs Li+/Li and 372.5 mAh g-1 (2.08 mAh cm-2) vs Na+/Na, respectively, in the second cycle under 0.1 A g–1. These results shed some light on the direct application of 3D flexible carbon sponge electrodes in high-performance LiBs/SiBs.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Qiduo Chen,Shan Tang,Dong Feng,Yuhui Xie,Feng Wu,Delong Xie,Yi Mei,Tianbiao Zeng
As a typical conversion alloyed anode material , Germanium selenide (GeSe 2 ) exhibits isotropic lithiation behavior and high theoretical charge-discharge specific capacity. However, pure GeSe 2 anode faces significant volume expansion (∼250 %−360 %) and further exploration is needed in the preparation of flexible electrode materials and structural design. Herein, a simple strategy is designed to load GeSe 2 /C-2 nanoparticles with porous carbon-coated structure on a flexible cross-networking substrate. The 3D network substrate is composed of highly conductive carbon nanotubes and adhesive cotton cellulose fibers. A two-step method involving coating and cross-linking is designed to achieve the fabrication of self-supporting flexible electrodes. As an anode for LIBs , the one layer GeSe 2 discs with ∼0.65 mm thickness manifest capacities of 827.1, 744.4, 676.3, and 472.9 mAh g −1 at 0.1, 0.2, 0.5, and 1 A g −1 , respectively. This superior Li + storage performance can be attributed to the positive collective impact from the integration of nano-scale material, low crystalline properties, and carbon sponge skeleton. Furthermore, the GITT tests indicate that the diffusion coefficient of Li + in the GeSe 2 -based electrodes ranged from 10 −15 to 10 −12 cm 2 /s, and the thickness of the flexible electrode (including two layers) has a negligible impact on its electrochemical performance.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2025
·
IF 7.9
Guanzheng Wang,Huazhi Lei,Zhong Liu,Zhentao Yuan,Lu Li,Zhaolin Zhan,Xiao Wang
Although GeO 2 exhibites a large theoretical capacity (2125 mAh g −1 ), its large volume change limits its wide application in anode materials. A novel oxygen-deficient and amorphous Ge/GeO 2 /C composite anode consisted of crystal Ge was synthesized in situ using hydrothermal methods and reductive sintering to improve the specific capacity and long life of GeO 2 -based anodes. The capacity of the Ge/GeO 2 /C anode is 1160 mAh g −1 at 0.2 A g −1 for 200 cycles. The reversible specific capacity is retained at 1004 mAh g −1 at A g −1 for 600 cycles, thereby showing excellent stability. The presence of rich oxygen vacancies and crystalline Ge can assist the reversible decomposition of amorphous GeO 2 to improve the ionic and electronic conductivity of the anode. In addition, a stable and uniform film thickness of ∼20 nm is formed at the Ge/GeO 2 /C electrode surfaces after down cycling 200 times, as observed by transmission electron microscopy. These excellent properties are due to the carbon composite, amorphous structure and high oxygen vacancy concentration of the anode and the synergistic effect by crystalline Ge.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 7
·期 1
·168-182
·
IF 8.683
Peiran Huang,Zuhui Wen,Yue Yu,Jingyi Xiao,Zhanhua Wei,Tianshuai Lyu
X-Ray or 254 nm UV-light charged storage phosphors have various promising applications such as in anti-counterfeiting and information storage. However, developing such storage phosphors with high charge carrier storage capacity remains challenging. In this work, photoluminescence spectroscopy, thermoluminescence (TL), and vacuum-referred binding energy (VRBE) diagram were combined to study the trapping and liberation processes of charge carriers in Bi3+ and/or Ln3+ (Ln = Tb, Pr, or Dy) doped LiLuGeO4. Unintended defects act as good electron trapping centers, while Bi3+, Tb3+, and Pr3+ act as hole-capturing and recombination centers. Dy3+ does not act as an electron trapping center but as a luminescence center by energy transfer from Bi3+ → Dy3+. The ratios of the integrated TL intensities between 303 K and 650 K for LiLuGeO4:0.005Bi3+, LiLuGeO4:0.005Bi3+,0.005Tb3+, or LiLuGeO4:0.005Bi3+,0.005Dy3+ after X-ray charging to that of the state-of-the-art BaFBr(I):Eu2+ is about 1.24, 0.59, and 0.90, respectively. More than 10 h or 40 h afterglow was measurable in both LiLuGeO4:0.005Bi3+ and LiLuGeO4:0.005Bi3+,0.005Tb3+ after X-ray or 254 nm UV-light charging. The stored charge carriers stored can be efficiently excited to produce optically stimulated luminescence with a wide range 365 nm UV-light to 850 nm infrared laser beam. Proof-of-concept colour-tailorable afterglow, X-ray irradiation time or sample mass-dependent dosimetry, and optically-stimulated luminescence with a wide range of 365 nm UV-light to 850 nm infrared laser stimulation will be demonstrated for anti-counterfeiting, information storage, and display applications in the developed Bi3+ and/or Ln3+-doped LiLuGeO4. This work not only reports Bi3+ and/or Ln3+ doped LiLuGeO4 storage phosphors with excellent charge carrier storage capacity but also deepens our understanding of the afterglow and storage phosphors and luminescence mechanisms, which can guide us to explore new afterglow and storage phosphors for multimode applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Nanoscale
·
2023
·Vol. 15
·期 9
·4438-4447
·
IF 6.7
Junyu Qu,Chenxi Liu,Muhammad Zubair,Zhouxiaosong Zeng,Bo Liu,Xin Yang,Ziyu Luo,Xiao Yi,Ying Chen,Shula Chen,Anlian Pan
Low-dimensional group IV–VI metal chalcogenide-based semiconductors hold great promise for opto-electronic device applications owing to their diverse crystalline phases and intriguing properties related to thermoelectric and ferroelectric effects. Herein, we demonstrate a universal chemical vapor deposition (CVD) growth method to synthesize stable germanium chalcogenide-based (GeS, GeS2, GeSe, GeSe2) nanosheets, which increases the library of the p-type semiconductor. The phase transition between different crystalline polytypes can be deterministically controlled by hydrogen concentration in the reaction chamber. Structural characterization and synthesis experiments identify the behavior, where the higher hydrogen concentration promotes the transiton from germanium dichalcogenides to germanium monochalcogenides. The angle-polarized and temperature-dependent Raman spectra demonstrate the strong interlayer coupling and lattice orientation. Based on the optimized growth scheme and systematic comparison of electrical properties, GeSe nanosheet photodetectors were demonstrated, which exhibit superior device performance on SiO2/Si and HfO2/Si substrate with a high photoresponsivity up to 104 A W−1, fast response time less than 15 ms, and high mobility of 3.2 cm2 V−1 s−1, which is comparable to the mechanically exfoliated crystals. Our results manifest the hydrogen-mediated deposition strategy as a facile control knob to engineer crystalline phases of germanium chalcogenides for high performance optoelectronic devices.
研究领域:
材料科学
·
半导体物理
·
光电子学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Guanzheng Wang,Huazhi Lei,Zhentao Yuan,Lu Li,Zhaolin Zhan,Xiao Wang
Although GeO 2 has a high theoretical capacity, its poor cyclic stability limits its application. In this work, amorphous GeO 2 /C composite anode materials were prepared by hydrothermal and sintering methods to improve the long-term cycle stability of Ge based anodes. The reversible specific capacity of the anode was 1300 mAh g −1 after 200 stable cycles at a current density of 0.2 A g −1 , and it was 1002 mAh g −1 after 1000 long cycles at a high current density of 1 A g −1 . The capacity retention rates of the amorphous GeO 2 /C-24 composite electrode were 84 % for the 2nd to the 200th discharge, being significantly higher than that of the commercial GeO 2 electrode (10 %). C doping changed the structure of GeO 2 atomic bonds and made C and O combine preferentially, resulting in Li + intercalating to the GeO 2 /C interface and the increase in the number of lithiation reaction sites, Li + diffusion coefficient, lithium-storage capacity and electrode capacity. The volume expansion rate of GeO 2 was reduced from 12.84 % to 2.51 % by C doping, resulting in the high structure stability of the anode in long cycles for LIBs. The reason was the stress release effect of the amorphous C coating, and the formation of a stable and appropriate thickness of the SEI film.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Haoyang Xu,Jiawen Zhang,Yifan Cheng,Yang Wang,Xuen Guo,Zhiqiang Zhang,Chaoqun Mu,Zhixian He,Juanqin Xue,Liang Zhang
A novel photocatalytic material, TiO 2 /STW-zeotype germanosilicate (GeSi-STW)/cellulose acetate (CA), has been successfully synthesized. During a 60 min photocatalytic degradation of tetracycline (TC), TiO 2 /GeSi-STW exhibited a rate constant of 0.02162 min −1 , which was notably higher than the values observed for pure TiO 2 (0.01373 min −1 ) and GeSi-STW (0.00277 min −1 ). SEM studies indicate that GeSi-STW serves as a support for TiO 2 , with TiO 2 being widely distributed on the surface of GeSi-STW. UV–vis DRS studies show that the introduction of GeSi-STW improves the low visible light absorption issue of TiO 2 . As revealed by PL and theoretical calculation outcomes, the combination of TiO 2 and GeSi-STW is capable of improving the situation where photogenerated carriers in the material tend to recombine easily. TiO 2 /GeSi-STW was successfully loaded onto CA, and TiO 2 /GeSi-STW was widely distributed in the pores of CA, which improved the problems of dispersion and difficulty of recycling of powder catalysts, and promoted the synergistic adsorption/photocatalysis of the material. TiO 2 /GeSi-STW/CA can quickly degrade TC without the need for additional oxidants and retains approximately 95 % of its original efficiency even after 5 cycles of reuse. The findings suggest that TiO 2 /GeSi-STW/CA holds significant potential for application in the treatment of antibiotic-contaminated wastewater.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Energy & Environmental Science
·
2025
·
IF 30.8
Kai Xu,Yuntian Fu,Wusheng Zuo,Meng Jiang,Xin Ai,Shun Wan,Hongyi Chen,Xiaofang Lu,Lianjun Wang,Qihao Zhang,Wan Jiang
The practical deployment of GeTe-based thermoelectrics has long been constrained by phase instability at elevated temperatures and severe interfacial degradation due to chemical diffusion and thermal expansion mismatches. Previous efforts to stabilize the high-performance cubic phase often result in incomplete phase suppression or compromised transport properties, while conventional electrode interface strategies exhibit poor thermomechanical reliability and inconsistent diffusion barriers. Here, we present a fully stabilized cubic GeTe system through Mn–Sb co-doping, maintaining phase stability from 300 to 750 K while simultaneously optimizing carrier concentration and electronic/thermal transport properties. This material achieves a peak zT of 1.73 at 773 K and an average zT of 1.0 across the operating range. To address interfacial instability, we introduce a cobalt diffusion barrier via magnetron sputtering, ensuring uniform coverage, good thermomechanical robustness, and a low contact resistivity of 5.2 μΩ cm2. These advancements enable the development of GeTe-based thermoelectric modules with an efficiency of 12.2% under a 480 K temperature gradient. By integrating precise phase stabilization with robust interface engineering, this study provides a viable pathway for mid-temperature waste heat recovery and reliable thermoelectric energy conversion.
研究领域:
材料科学
·
热电学
·
固体物理
·
能源材料
·
功能材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）