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Sodium intercalated manganese thiophosphate Na0.62Mn0.69PS3 powders have been synthesized by a two-step ion-exchange process. Dielectric measurements have been performed as a function of both temperature and frequency on the prepared samples in the 20–106 Hz frequency range over the 78–350 K temperature range by using the autobalancing bridge method. The temperature dependence of the dielectric constant imaginary part reveals the presence of a loss peak at the low temperatures together with a strong dispersion at the low frequencies and at the highest investigated temperatures. While the loss peak presence is characteristic for dipolar polarization processes, the strong low frequency dispersion at not very high temperatures, observed also in the dielectric constant real part, is typical for system with hopping charge carriers. A hypothesis about the nature of such carriers has been formulated on the basis of both the ion-exchange intercalation process and the comparison with the dielectric spectra previously observed for cesium intercalated manganese thiophosphate Cs0.46Mn0.77PS3 compounds. [ABSTRACT FROM AUTHOR]

Polycrystalline powders of Na2xMn1-xPS3 have been synthesized from layered MnPS3 material by successive ion-exchange intercalation of potassium and sodium ions. Their x-ray photoelectron spectroscopy (XPS) and x-ray excited Auger spectroscopy spectra have been measured at room temperature using Mg Kα (1253.6 eV) x-ray source. In particular, the Mn, P, and S 2p and Na 1s and 2p core-level regions and the Na Auger KL23L23 transition have been investigated. All the analyzed XPS core-level spectra display a single-peak structure, suggesting the absence of nonequivalent atoms of Na, Mn, P, and S. The manganese XPS spectrum shows, as observed in MnPS3 and in its cesium and potassium intercalation compounds, typical shake-up satellites, suggesting that the Mn–S bond is yet mainly ionic in nature. The comparison with the XPS spectra relative to MnPS3 and its potassium intercalation compound (K2xMn1-xPS3) does not emphasize any relevant difference in the binding energy positions of the investigated core levels, indicating that sodium ion intercalation process does not alter the electronic properties of pure host matrix. Moreover, Na 2p core levels are discrete and well localized in agreement with the hypothesis of a weak link between the guest (the Na+ ions) and the host lattice (the negatively charged Mn1-xPS3 sheets). Such a hypothesis finds confirmation by the calculation of the Na modified Auger parameter. [ABSTRACT FROM AUTHOR]

Li2xMn1-xPS3films have been synthesized by exfoliating MnPS3through the successive intercalations of K+and Li+ions. Their dielectric response has been measured from 80 to 350 K in the frequency range of (102–106) Hz. The obtained data have been analyzed in terms of both complex permittivityε*and theacconductivityσac. The frequency dependence ofσachas been interpreted in terms of the Jonscher’s law, whose exponentndecreases by increasing temperature. Thenvalues lie between 0.479 and 0.501 and are typical of materials in which theacconductivity is due to multiple hops of carriers. By analyzing theσdctemperature dependence, the observed dielectric response has been attributed to the intercalated lithium ions, and the Li2xMn1-xPS3films have been classified ashoppingcharge carrier systems. [ABSTRACT FROM AUTHOR]

Highlights: [•] 9-aminoacridine intercalation was performed in thin films of exfoliated Li2x Mn1−x PS3. [•] Li2x−y Mn1−x PS3(C13H11N2) y and C13H11N2Cl film XPS spectra were investigated. [•] XPS spectra confirm that the 9-aminoacridine molecule is protonated in both films. [•] The interaction between 9AAH+ (guest) and Li2x−y Mn1−x PS3 − (host) is electrostatic. [•] Mn2+ in Li2x−y Mn1−x PS3(C13H11N2) y films is in the high spin state as in MnPS3. [ABSTRACT FROM AUTHOR]

Abstract: Manganese thiophosphate powders have been intercalated with sodium ions at two different intercalation times (150min and 180min) in order to evaluate the influence of this parameter on the dielectric properties of the obtained compounds labeled like Na2x Mn1−x PS3. In particular, dielectric permittivity measures have been carried out as a function of temperature (80K–350K) and frequency (20Hz to 1MHz) and compared with each other and with those of the pure matrix and of the Na2x Mn1−x PS3 compound corresponding to a 120min intercalation time. Both investigated compounds show a dielectric response characterized by a loss peak at low temperatures, by a strong dispersion at low frequency and at not very high temperatures and by a crossover frequency showing an Arrhenius temperature dependence in agreement with what already observed in Na2x Mn1−x PS3 (120min). The results have been also discussed in terms of ac conductivity, Maxwell–Wagner–Sillar (MWS) polarization, electrode polarization and dc conductivity and all the above cited features have been attributed to the Na+ ions which are, by their nature, hopping charge carriers that behave like jumping dipoles in their alternate motions and simultaneously show conducting characteristics resulting from their extended hopping over many sites. This attribution allows us to classify the analyzed sodium compounds like hopping charge carrier systems in which a greater Na intercalation time translates into a decrease in the loss peak intensity and an increase in the activation energy associated to the crossover frequency. [Copyright &y& Elsevier]

Abstract: Na0.88Mn0.56PS3compounds have been synthesized by starting from MnPS3 polycrystalline powders by means of a two-step cation-exchange process at a higher intercalation time than the one used for producing the literature reported Na0.62Mn0.69PS3 compounds. The obtained samples have been characterized by X-ray photoelectron spectroscopy (XPS). The resulting spectra of the so-synthesized compounds have been compared with those observed in Na0.62Mn0.69PS3 in our previous paper and similar electronic properties have been noted. In particular by XPS it has been shown that greater sodium content affects neither the core-level binding energies of the host matrix elements nor the type of link between Na+ and (Mn1−x PS3)−. [Copyright &y& Elsevier]