Hachem Araji, Maria Nakhoul, Elio Challita, Nour Barmo and Brigitte Wex
Pyrene and acene derivatives are an important source of materials for optoelectronic device applications both as emitters and organic semiconductors. The mobility of major charge carriers is correlated with the coupling constants of the respective major charge carrier as well as the relaxation energies. Herein, we have applied range-separated density functionals for the estimation of said values. A series of five alkylated derivatives of pyrene laterally extended by heteroaromatic or phenyl groups were explored and contrasted to nascent pyrene, alkylated pyrene and tetracene. The ground state geometries along with absorption properties and relaxation energies are presented as well as a discussion of the suitability of the material toward hole and electron transport materials.
{"title":"Cross-over from pyrene to acene optical and electronic properties: a theoretical investigation of a series of pyrene derivatives fused with N-, S, and O-containing heterocycles†","authors":"Hachem Araji, Maria Nakhoul, Elio Challita, Nour Barmo and Brigitte Wex","doi":"10.1039/D4CP01625D","DOIUrl":"10.1039/D4CP01625D","url":null,"abstract":"<p >Pyrene and acene derivatives are an important source of materials for optoelectronic device applications both as emitters and organic semiconductors. The mobility of major charge carriers is correlated with the coupling constants of the respective major charge carrier as well as the relaxation energies. Herein, we have applied range-separated density functionals for the estimation of said values. A series of five alkylated derivatives of pyrene laterally extended by heteroaromatic or phenyl groups were explored and contrasted to nascent pyrene, alkylated pyrene and tetracene. The ground state geometries along with absorption properties and relaxation energies are presented as well as a discussion of the suitability of the material toward hole and electron transport materials.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetsuroh Shirasawa, Wolfgang Voegeli and Etsuo Arakawa
X-ray absorption spectroscopy (XAS) and small-angle X-ray scattering (SAXS) are common materials characterization tools at synchrotron radiation facilities used in many research fields. Since XAS can provide element-specific chemical states and local atomic structures and SAXS can provide nano-scale structural information, their complementary use is advantageous for a comprehensive understanding of multiscale phenomena. This paper presents a new method for simultaneous XAS/SAXS measurements with synchrotron radiation. The method employs a polychromatic X-ray beam as in the energy-dispersive XAS technique and captures both the transmission XAS spectrum and the SAXS intensity distribution with an area X-ray detector, which eliminates the energy scan in the conventional methods and realizes the simultaneous data acquisition in a shorter time. We succeeded in obtaining the atomic and nano-scale structures of Pt and Pt/Pd nanoparticles with a data acquisition time of 0.1 s, suggesting the potential for real-time observation of multiscale phenomena.
X 射线吸收光谱（XAS）和小角 X 射线散射（SAXS）是同步辐射设施中常用的材料表征工具，可用于许多研究领域。由于 XAS 可以提供特定元素的化学状态和局部原子结构，而 SAXS 可以提供纳米尺度的结构信息，因此二者的互补使用有利于全面了解多尺度现象。本文介绍了一种利用同步辐射同时测量 XAS/SAXS 的新方法。该方法采用了能量色散 XAS 技术中的多色 X 射线束，并通过一个面积 X 射线探测器同时捕获透射 XAS 光谱和 SAXS 强度分布，从而省去了传统方法中的能量扫描，在更短的时间内实现了同步数据采集。我们成功地在 0.1 秒的数据采集时间内获得了铂和铂/钯纳米粒子的原子和纳米尺度结构，为实时观测多尺度现象提供了可能。
{"title":"Simultaneous fast XAS/SAXS measurements in an energy-dispersive mode†","authors":"Tetsuroh Shirasawa, Wolfgang Voegeli and Etsuo Arakawa","doi":"10.1039/D4CP01399A","DOIUrl":"10.1039/D4CP01399A","url":null,"abstract":"<p >X-ray absorption spectroscopy (XAS) and small-angle X-ray scattering (SAXS) are common materials characterization tools at synchrotron radiation facilities used in many research fields. Since XAS can provide element-specific chemical states and local atomic structures and SAXS can provide nano-scale structural information, their complementary use is advantageous for a comprehensive understanding of multiscale phenomena. This paper presents a new method for simultaneous XAS/SAXS measurements with synchrotron radiation. The method employs a polychromatic X-ray beam as in the energy-dispersive XAS technique and captures both the transmission XAS spectrum and the SAXS intensity distribution with an area X-ray detector, which eliminates the energy scan in the conventional methods and realizes the simultaneous data acquisition in a shorter time. We succeeded in obtaining the atomic and nano-scale structures of Pt and Pt/Pd nanoparticles with a data acquisition time of 0.1 s, suggesting the potential for real-time observation of multiscale phenomena.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohammad Khazaei, Iraj Maleki Shahrivar, Namitha Anna Koshi, Ahmad Ranjbar, Nanxi Miao, Junjie Wang, Rasoul Khaledialidusti, Thomas D. Kühne, Seung Cheol Lee, Satadeep Bhattacharjee, Hamid Hosano, S. Mehdi Vaez Allaei, Keivan Esfarjani, Kaoru Ohno
MAX phase is a family of ceramic compounds, typically known for their metal- lic properties. However, we show here that some of them may be narrow bandgap semiconductors. Using a series of first-principles calculations, we have investigated the electronic structures of 861 dynamically stable MAX phases. Notably, Sc2SC, Y2SC, Y2SeC, Sc3AuC2, and Y3AuC2 have been iden- tified as semiconductors with band gaps ranging from 0.2 to 0.5 eV. Further- more, we have assessed the thermodynamic stability of these systems by gen- erating ternary phase diagrams utilizing evolutionary algorithm techniques. Their dynamic stabilities are confirmed by phonon calculations. Additionally, we have explored the potential thermoelectric efficiencies of these materials by combining Boltzmann transport theory with first-principles calculations. The relaxation times are estimated using scattering theory. The zT coefficients for the aforementioned systems fall within the range of 0.5 to 2.5 at temperatures spanning from 300 to 700 K, indicating their suitability for high-temperature thermoelectric applications.
MAX 相是陶瓷化合物的一个家族，通常以其金属许可特性而闻名。然而，我们在此发现其中一些可能是窄带隙半导体。通过一系列第一性原理计算，我们研究了 861 种动态稳定的 MAX 相的电子结构。值得注意的是，Sc2SC、Y2SC、Y2SeC、Sc3AuC2 和 Y3AuC2 被确定为带隙范围为 0.2 至 0.5 eV 的半导体。此外，我们还利用进化算法技术绘制了三元相图，评估了这些系统的热力学稳定性。声子计算证实了它们的动态稳定性。此外，我们还将玻尔兹曼输运理论与第一原理计算相结合，探索了这些材料的潜在热电效率。我们利用散射理论估算了弛豫时间。上述系统在 300 至 700 K 温度范围内的 zT 系数在 0.5 至 2.5 之间，表明它们适合高温热电应用。
{"title":"Beyond Metals: Theoretical Discovery of Semiconducting MAX Phases and their Potential Application in Thermoelectrics","authors":"Mohammad Khazaei, Iraj Maleki Shahrivar, Namitha Anna Koshi, Ahmad Ranjbar, Nanxi Miao, Junjie Wang, Rasoul Khaledialidusti, Thomas D. Kühne, Seung Cheol Lee, Satadeep Bhattacharjee, Hamid Hosano, S. Mehdi Vaez Allaei, Keivan Esfarjani, Kaoru Ohno","doi":"10.1039/d4cp01950d","DOIUrl":"https://doi.org/10.1039/d4cp01950d","url":null,"abstract":"MAX phase is a family of ceramic compounds, typically known for their metal- lic properties. However, we show here that some of them may be narrow bandgap semiconductors. Using a series of first-principles calculations, we have investigated the electronic structures of 861 dynamically stable MAX phases. Notably, Sc2SC, Y2SC, Y2SeC, Sc3AuC2, and Y3AuC2 have been iden- tified as semiconductors with band gaps ranging from 0.2 to 0.5 eV. Further- more, we have assessed the thermodynamic stability of these systems by gen- erating ternary phase diagrams utilizing evolutionary algorithm techniques. Their dynamic stabilities are confirmed by phonon calculations. Additionally, we have explored the potential thermoelectric efficiencies of these materials by combining Boltzmann transport theory with first-principles calculations. The relaxation times are estimated using scattering theory. The zT coefficients for the aforementioned systems fall within the range of 0.5 to 2.5 at temperatures spanning from 300 to 700 K, indicating their suitability for high-temperature thermoelectric applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Till Johann, Weiwei Xie, Sara Roosta, Marcus Elstner, Martijn Kemerink
In this work, the ferroelectric and semiconducting properties of the organic semiconducting ferroelectric benzotrithiophene tricarboxamide (BTTTA), and especially their nonlinear coupling, are theoretically investigated. BTTTA is an exponent of a small class of semiconducting organic ferroelectrics for which experiments have established a surprising polarization direction dependence of the bulk conductivity at finite fields. First, molecular dynamics (MD) simulations are used to investigate the occurrence and, under the influence of an external electric field, the inversion of the macroscopic electric dipole that forms along the axis of supramolecular columns of BTTTA. The MD results are consistent with the experimentally observed ferroelectric behavior of the material. Building on the MD results, a QM/MM scheme is used to investigate the charge carrier mobility in the quasi-1D BTTTA stacks in the linear and non-linear regimes. Indeed, at finite electric fields, a clear resistance switching effect was observed in the form of a hole mobility that is a factor ∼2 larger for antiparallel orientations of the polarization and field than for a parallel orientation. This phenomenon can be understood as a microscopic ratchet that is based on the non-equilibrium interaction between the (oriented) dipoles and the (direction of the) charge transport.
{"title":"Theory for nonlinear conductivity switching in semiconducting organic ferroelectrics","authors":"Till Johann, Weiwei Xie, Sara Roosta, Marcus Elstner, Martijn Kemerink","doi":"10.1039/d4cp01632g","DOIUrl":"https://doi.org/10.1039/d4cp01632g","url":null,"abstract":"In this work, the ferroelectric and semiconducting properties of the organic semiconducting ferroelectric benzotrithiophene tricarboxamide (BTTTA), and especially their nonlinear coupling, are theoretically investigated. BTTTA is an exponent of a small class of semiconducting organic ferroelectrics for which experiments have established a surprising polarization direction dependence of the bulk conductivity at finite fields. First, molecular dynamics (MD) simulations are used to investigate the occurrence and, under the influence of an external electric field, the inversion of the macroscopic electric dipole that forms along the axis of supramolecular columns of BTTTA. The MD results are consistent with the experimentally observed ferroelectric behavior of the material. Building on the MD results, a QM/MM scheme is used to investigate the charge carrier mobility in the quasi-1D BTTTA stacks in the linear and non-linear regimes. Indeed, at finite electric fields, a clear resistance switching effect was observed in the form of a hole mobility that is a factor ∼2 larger for antiparallel orientations of the polarization and field than for a parallel orientation. This phenomenon can be understood as a microscopic ratchet that is based on the non-equilibrium interaction between the (oriented) dipoles and the (direction of the) charge transport.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing more energy-efficient and cost-effective membrane processes for the separation of ethanol and water represents a strategically important direction to facilitate the production of renewable biofuels. In this study, by employing state-of-the-art molecular simulations, the potential of zeolite nanosheets as reverse osmosis (RO) membranes in ethanol/water separation is investigated. These materials are predicted to offer unprecedentedly high fluxes and more importantly, the ethanol-to-water separation factor can be as large as approximately 800 if the structure is meticulously selected. The separation achieved herein can in fact be considered counter-intuitive as the membrane allows the larger ethanol molecules to permeate through while blocking smaller water molecules. Further investigations reveal that the observed selectivity is strongly correlated to the adsorption selectivity of the bulk materials, suggesting an adsorption-driven mechanism. Promising candidates also appear to have the largest cavity diameter of approximately 6 Å, a size that can be commensurate with the dimension of ethanol to facilitate their adsorption. The hydrophilicity on the membrane surfaces is as well found to play a non-negligible role. Overall, this study demonstrates the great promise of zeolite nanosheets as RO membranes for extracting anhydrous ethanol from its aqueous mixture and provides guidance toward the selection of promising membrane candidates.
{"title":"Adsorption-driven Reverse Osmosis Separation of Ethanol/Water Using Zeolite Nanosheets","authors":"Yen-Yung Wu, Li-Chiang Lin","doi":"10.1039/d4cp01830c","DOIUrl":"https://doi.org/10.1039/d4cp01830c","url":null,"abstract":"Developing more energy-efficient and cost-effective membrane processes for the separation of ethanol and water represents a strategically important direction to facilitate the production of renewable biofuels. In this study, by employing state-of-the-art molecular simulations, the potential of zeolite nanosheets as reverse osmosis (RO) membranes in ethanol/water separation is investigated. These materials are predicted to offer unprecedentedly high fluxes and more importantly, the ethanol-to-water separation factor can be as large as approximately 800 if the structure is meticulously selected. The separation achieved herein can in fact be considered counter-intuitive as the membrane allows the larger ethanol molecules to permeate through while blocking smaller water molecules. Further investigations reveal that the observed selectivity is strongly correlated to the adsorption selectivity of the bulk materials, suggesting an adsorption-driven mechanism. Promising candidates also appear to have the largest cavity diameter of approximately 6 Å, a size that can be commensurate with the dimension of ethanol to facilitate their adsorption. The hydrophilicity on the membrane surfaces is as well found to play a non-negligible role. Overall, this study demonstrates the great promise of zeolite nanosheets as RO membranes for extracting anhydrous ethanol from its aqueous mixture and provides guidance toward the selection of promising membrane candidates.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the importance of MgO$^+$ for understanding the electronic structure and chemical bonds in the alkaline-earth metal oxides and its potential astrophysical relevance, hardly any spectroscopic information is available on this molecular cation. We report on a high-resolution photoelectron spectroscopic study of MgO using a resonant 1+1$^{prime}$ two-photon excitation scheme in combination with PFI-ZEKE photoelectron spectroscopy. By carrying out the resonant excitation via selected rotational levels of several intermediate states of different electronic configurations, total electronic spins, and internuclear distances, a broad range of vibrational levels of the X$^+~^2Pi_{Omega}~(Omega=3/2,1/2)$ ground and A$^+~^2Sigma^+$ first excited states of MgO$^+$ were observed for the first time. The new data provide a full characterisation of the rovibronic level structure of MgO$^+$ up to 2 eV (16000 cm$^{-1}$) of internal energy. A full set of vibrational, rotational and spin-orbit-coupling molecular constants were extracted for these two electronic states. The adiabatic ionisation energy and the singlet-triplet interval of $^{24}$Mg$^{16}$O were determined to be 65474.7(2) cm$^{-1}$ and 2492.4(3) cm$^{-1}$, respectively.
{"title":"Characterisation of the ground X$^+$ $^2Pi_{Omega}$ and first excited A$^+$ $^2Sigma^+$ electronic states of MgO$^+$ by high-resolution photoelectron spectroscopy","authors":"Carla Kreis, Joel R. Schmitz, Frédéric Merkt","doi":"10.1039/d4cp01944j","DOIUrl":"https://doi.org/10.1039/d4cp01944j","url":null,"abstract":"Despite the importance of MgO$^+$ for understanding the electronic structure and chemical bonds in the alkaline-earth metal oxides and its potential astrophysical relevance, hardly any spectroscopic information is available on this molecular cation. We report on a high-resolution photoelectron spectroscopic study of MgO using a resonant 1+1$^{prime}$ two-photon excitation scheme in combination with PFI-ZEKE photoelectron spectroscopy. By carrying out the resonant excitation via selected rotational levels of several intermediate states of different electronic configurations, total electronic spins, and internuclear distances, a broad range of vibrational levels of the X$^+~^2Pi_{Omega}~(Omega=3/2,1/2)$ ground and A$^+~^2Sigma^+$ first excited states of MgO$^+$ were observed for the first time. The new data provide a full characterisation of the rovibronic level structure of MgO$^+$ up to 2 eV (16000 cm$^{-1}$) of internal energy. A full set of vibrational, rotational and spin-orbit-coupling molecular constants were extracted for these two electronic states. The adiabatic ionisation energy and the singlet-triplet interval of $^{24}$Mg$^{16}$O were determined to be 65474.7(2) cm$^{-1}$ and 2492.4(3) cm$^{-1}$, respectively.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, using the tight-binding model and Green's function technique, we investigate potential electronic phase transitions in bilayer P6mmm borophene under the influence of external stimuli, including a perpendicular electric field, electron-hole coupling between sublayers (excitonic effects), and dopants. Our focus is on key electronic properties such as the band structure and density of states. Our findings reveal that the pristine lattice is metal with Dirac cones around the Fermi level, where their intersection forms a nodal line. The system undergoes transitions to a semiconducting state -- elimination of nodal line -- with a perpendicular electric field and a semimetallic state -- transition from two Dirac cones to a single Dirac cone -- with combined electric field and excitonic effects. Notably, with these, the system retains its massless Dirac-like bands characteristic at finite energy. However, introducing a dopant still leads to a metallic phase, but the Dirac-like bands become massive. Considering all these effects, the system ultimately reaches a semiconducting phase with massive Dirac-like bands. These results hold significance for optoelectronic applications.
{"title":"Electronic phase transition in bilayer P6mmm borophene","authors":"Nguyen N. Hieu, Huynh V. Phuc, Bui D. Hoi","doi":"10.1039/d4cp01484g","DOIUrl":"https://doi.org/10.1039/d4cp01484g","url":null,"abstract":"In this study, using the tight-binding model and Green's function technique, we investigate potential electronic phase transitions in bilayer P6mmm borophene under the influence of external stimuli, including a perpendicular electric field, electron-hole coupling between sublayers (excitonic effects), and dopants. Our focus is on key electronic properties such as the band structure and density of states. Our findings reveal that the pristine lattice is metal with Dirac cones around the Fermi level, where their intersection forms a nodal line. The system undergoes transitions to a semiconducting state -- elimination of nodal line -- with a perpendicular electric field and a semimetallic state -- transition from two Dirac cones to a single Dirac cone -- with combined electric field and excitonic effects. Notably, with these, the system retains its massless Dirac-like bands characteristic at finite energy. However, introducing a dopant still leads to a metallic phase, but the Dirac-like bands become massive. Considering all these effects, the system ultimately reaches a semiconducting phase with massive Dirac-like bands. These results hold significance for optoelectronic applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thi Luu Luyen Doan, Minh Xuan Tran, Dang Le Tri Nguyen and Dinh Chuong Nguyen
In this study, we developed a high-performance non-enzymatic electrochemical sensor based on urchin-like CoP3/Cu3P heterostructured nanorods supported on a three-dimensional porous copper foam, namely, CoP3/Cu3P NRs/CF, for the detection of dopamine. Benefiting from the promising intrinsic catalytic activities of CoP3 and Cu3P, urchin-like microsphere structures, and a large electrochemically active surface area for exposing numerous accessible catalytic active sites, the proposed CoP3/Cu3P NRs/CF shows extraordinary electrochemical response towards the electrocatalytic oxidation of dopamine. As a result, the CoP3/Cu3P NRs/CF sensing electrode has a broad detection window (from 0.2 to 2000 μM), low detection limit (0.51 μM), high electrochemical sensitivity (0.0105 mA μM−1 cm−2), excellent selectivity towards dopamine in the coexistence of some interfering species, and good stability for dopamine determination. More importantly, the CoP3/Cu3P NRs/CF catalyst also exhibits excellent catalytic activity, sensitivity, and selectivity for dopamine detection under simulated human body conditions at a physiological pH of 7.25 (0.1 M PBS) at 36.6 °C.
{"title":"Urchin-like CoP3/Cu3P heterostructured nanorods supported on a 3D porous copper foam for high-performance non-enzymatic electrochemical dopamine sensors†","authors":"Thi Luu Luyen Doan, Minh Xuan Tran, Dang Le Tri Nguyen and Dinh Chuong Nguyen","doi":"10.1039/D3CP04340A","DOIUrl":"10.1039/D3CP04340A","url":null,"abstract":"<p >In this study, we developed a high-performance non-enzymatic electrochemical sensor based on urchin-like CoP<small><sub>3</sub></small>/Cu<small><sub>3</sub></small>P heterostructured nanorods supported on a three-dimensional porous copper foam, namely, CoP<small><sub>3</sub></small>/Cu<small><sub>3</sub></small>P NRs/CF, for the detection of dopamine. Benefiting from the promising intrinsic catalytic activities of CoP<small><sub>3</sub></small> and Cu<small><sub>3</sub></small>P, urchin-like microsphere structures, and a large electrochemically active surface area for exposing numerous accessible catalytic active sites, the proposed CoP<small><sub>3</sub></small>/Cu<small><sub>3</sub></small>P NRs/CF shows extraordinary electrochemical response towards the electrocatalytic oxidation of dopamine. As a result, the CoP<small><sub>3</sub></small>/Cu<small><sub>3</sub></small>P NRs/CF sensing electrode has a broad detection window (from 0.2 to 2000 μM), low detection limit (0.51 μM), high electrochemical sensitivity (0.0105 mA μM<small><sup>−1</sup></small> cm<small><sup>−2</sup></small>), excellent selectivity towards dopamine in the coexistence of some interfering species, and good stability for dopamine determination. More importantly, the CoP<small><sub>3</sub></small>/Cu<small><sub>3</sub></small>P NRs/CF catalyst also exhibits excellent catalytic activity, sensitivity, and selectivity for dopamine detection under simulated human body conditions at a physiological pH of 7.25 (0.1 M PBS) at 36.6 °C.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Semiconductor nano-crystals as well as two-dimensional nanostructures manifest an abnormal dependence on the temperature of the optical band gap energy. In contrast to bulk systems, in the present case the optical band gap energy increases with temperature or may show a non-monotonic blueshift-redshift behavior. It was suggested that this abnormal temperature behavior is associated with the recombination of excitons and free electron-hole pairs under conditions of quantum confinement. Here, we show that the presence of nanometer lengths and anharmonic interactions makes it necessary to rescale the energy and thermal energy of the material according to the invariance of statistical mechanics on the energy/thermal-energy ratio. In addition, considering the effects of the thermal expansion of the material, we managed to derive a formula for the optical band gap energy. Using this formula, the photoluminescence spectra are accounted for by emphasizing that the exciton and free electron-hole pairs recombination is a non-thermal statistical process following a Poisson distribution in which the average value of the energy and the full width at half maximum are both directly related to the optical band gap energy. Our results accounts remarkably well for several experimental data reported in recent literature.
{"title":"A statistical theory of the photoluminescent determination of the band gap energy in nano-crystals and layered materials","authors":"I. Santamaria-Holek, Agustin Perez-Madrid","doi":"10.1039/d4cp01772b","DOIUrl":"https://doi.org/10.1039/d4cp01772b","url":null,"abstract":"Semiconductor nano-crystals as well as two-dimensional nanostructures manifest an abnormal dependence on the temperature of the optical band gap energy. In contrast to bulk systems, in the present case the optical band gap energy increases with temperature or may show a non-monotonic blueshift-redshift behavior. It was suggested that this abnormal temperature behavior is associated with the recombination of excitons and free electron-hole pairs under conditions of quantum confinement. Here, we show that the presence of nanometer lengths and anharmonic interactions makes it necessary to rescale the energy and thermal energy of the material according to the invariance of statistical mechanics on the energy/thermal-energy ratio. In addition, considering the effects of the thermal expansion of the material, we managed to derive a formula for the optical band gap energy. Using this formula, the photoluminescence spectra are accounted for by emphasizing that the exciton and free electron-hole pairs recombination is a non-thermal statistical process following a Poisson distribution in which the average value of the energy and the full width at half maximum are both directly related to the optical band gap energy. Our results accounts remarkably well for several experimental data reported in recent literature.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manganese-based MXenes are promising two-dimensional materials due to the broad palette of their magnetic phases and the possibility of experimental preparation because the corresponding MAX phase was already prepared. Here, we systematically investigated geometrical conformers and spin solutions of oxygen-terminated Mn2C MXene and performed subsequent many-body calculations to obtain reliable electronic and optical properties. Allowing energy-lowering using the correct spin ordering via supercell magnetic motifs is essential for Mn2CO2 system. The stable ground-state Mn2CO2 conformation is antiferromagnetic (AFM) one with zigzag lines of up and down spins on Mn atoms. The AFM nature is consistent with the parent MAX phase and even the clean depleted Mn2C sheet. Other magnetic states and geometrical conformations are energetically very close, providing state-switching possibilities in the material. Subsequent many-body GW and Bethe-Salpeter equation (BSE) calculations provide indirect semiconductor characteristics of AFM Mn2CO2 with a fundamental gap of 2.1 eV (and a direct gap of 2.4 eV), the first bright optical transition at 1.3 eV and extremely strongly bounded (1.1 eV) first bright exciton. Mn2CO2 absorbs efficiently the whole visible light range and near ultraviolet range (between 10 - 20%).
{"title":"Mn2C MXene Functionalized by Oxygen is a Semiconducting Antiferromagnet and Efficient Visible Light Absorber","authors":"Jiri Kalmar, Frantisek Karlicky","doi":"10.1039/d4cp02264e","DOIUrl":"https://doi.org/10.1039/d4cp02264e","url":null,"abstract":"Manganese-based MXenes are promising two-dimensional materials due to the broad palette of their magnetic phases and the possibility of experimental preparation because the corresponding MAX phase was already prepared. Here, we systematically investigated geometrical conformers and spin solutions of oxygen-terminated Mn<small><sub>2</sub></small>C MXene and performed subsequent many-body calculations to obtain reliable electronic and optical properties. Allowing energy-lowering using the correct spin ordering via supercell magnetic motifs is essential for Mn<small><sub>2</sub></small>CO<small><sub>2</sub></small> system. The stable ground-state Mn<small><sub>2</sub></small>CO<small><sub>2</sub></small> conformation is antiferromagnetic (AFM) one with zigzag lines of up and down spins on Mn atoms. The AFM nature is consistent with the parent MAX phase and even the clean depleted Mn<small><sub>2</sub></small>C sheet. Other magnetic states and geometrical conformations are energetically very close, providing state-switching possibilities in the material. Subsequent many-body GW and Bethe-Salpeter equation (BSE) calculations provide indirect semiconductor characteristics of AFM Mn<small><sub>2</sub></small>CO<small><sub>2</sub></small> with a fundamental gap of 2.1 eV (and a direct gap of 2.4 eV), the first bright optical transition at 1.3 eV and extremely strongly bounded (1.1 eV) first bright exciton. Mn<small><sub>2</sub></small>CO<small><sub>2</sub></small> absorbs efficiently the whole visible light range and near ultraviolet range (between 10 - 20%).","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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