Variation of electronic phases in (R1R2DCNQI)2Ag: systematic change of the one-dimensional band by chemical substitution of R1 and R2

Hiraki, K.; Kanoda, K.

doi:10.1016/s0379-6779(98)00446-9

Cited by 10 publications

(4 citation statements)

References 7 publications

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“…5 and 6, respectively. The physical behavior of the pristine salt quantitatively agreed with previously reported one [32][33][34][35][36][37][38][39][40][41][42][43]. Ag(DI) 2 exhibited semiconducting behavior, i.e.…”

Section: Photochemical Control Of Electrical and Magnetic Propertiessupporting

confidence: 87%

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Photochemical modification of magnetic properties in organic low-dimensional conductors

Naito

Kakizaki

Wakeshima

et al. 2009

Journal of Solid State Chemistry

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Magnetic properties of organic charge transfer salts Ag(DX) 2 (DX = 2,5-dihalogeno-N,N'-dicyanoquinonediimine; X = Cl, Br, I) were modified by UV irradiation from paramagnetism to diamagnetism in an irreversible way. The temperature dependence of susceptibility revealed that such change in magnetic behavior could be continuously controlled by the duration of irradiation. The observation with scanning electron microprobe revealed that the original appearance of samples, e.g. black well-defined needle-shaped shiny single crystals, remained after irradiation irrespective of the irradiation conditions and the duration. Thermochemical analysis and X-ray diffraction study demonstrated that the change in the physical properties were due to (partial) decomposition of Ag(DX) 2 to AgX, which was incorporated in the original Ag(DX) 2 lattices. Because the physical properties of  Corresponding author: tnaito@sci.hokudai.ac.jp 2 low-dimensional organic conductors are very sensitive to lattice defects, even a small amount of AgX could effectively modify the electronic properties of Ag(DX) 2 without making the original crystalline appearance collapse.

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Section: Photochemical Control Of Electrical and Magnetic Propertiessupporting

confidence: 87%

“…All Ag(DX) 2 (X = Cl, Br, I) are known to be isomorphous [22,23,[32][33][34][35][36][37][38][39][40][41][42] from X-ray measurements of their lattice parameters, yet their full structural analyses (atomic parameters) have not been reported.…”

Section: Crystal Structures Of Pristine Ag(dx)mentioning

confidence: 99%

Photochemical modification of magnetic properties in organic low-dimensional conductors

Naito

Kakizaki

Wakeshima

et al. 2009

Journal of Solid State Chemistry

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“…Ag(DMe-DCNQI) 2 is a well studied compound [3], yet the effect of the photosensitivity of Ag(I) ions towards UV-VIS light on its physical properties have remained unknown. Recently we have found significant differences in the electrical and magnetic behaviour between the pristine and exposed crystals [2].…”

Section: Uv-vis Exposure Effects On the Electrical And Magnetic Propementioning

confidence: 99%

Molecular conductors containing photoreactive species

Naito

Inabe

2004

J. Phys. IV France

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In order to examine the possibility of (persistent) carrier doping to molecular crystals by light exposure, some different types of molecular crystals containing photoreactive species are synthesized and characterized. The [Ru(bpy) 3 ] 2+ cation (bpy = 2,2'-bipyridyl) yielded two different new complexes with [Ni(dmit) 2 ]radical species, both of which were structurally characterized and turned out to be band insulators. Methy viologen (MV) has been found to yield a new phase of the complex with [Ni(dmit) 2 ]-, MV[Ni(dmit) 2 ] 2. The temperature dependences of electrical resistivity (decreasing with lowering temperature down to 1.0 K) and magnetic susceptibility (Pauli paramagnetism from 300 K to 1.8 K with a hysteresis below ~ 100 K) clearly indicate that this phase is metallic. The thermoelectric power exhibited ~0 µVK-1 from 300 K-4.2 K. This phase turned out to be metastable, and the crystals gradually turned into insulating ones. The effects of UV-VIS light exposure to the conducting and magnetic properties of Ag(DMe-DCNQI) 2 have been studied, and clear differences between the exposed and the pristine crystals were observed. The ESR signal at 3.7 K suggested that the exposed sample should include the Ag(0) species.

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“…The Ag is connected with four DM molecules in a pseudotetrahedral through a coordinate bond. It has one-dimensional (1D) metallic conduction at room temperature (RT). − The 1D metallic conduction of α is mainly due to two factors: (1) DM molecules assemble in a columnar structure along the c axis and interact through π−π overlaps, creating a 1D π band. (2) DM molecules accept unpaired electrons from Ag atoms, which are accommodated in the 1D π orbitals and behave as conduction electrons.…”

Section: Introductionmentioning

confidence: 99%

Origin of Photochemical Modification of the Resistivity of Ag(DMe-DCNQI)₂ Studied by X-ray Absorption Fine Structure

et al. 2009

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The Ag(DMe-DCNQI) 2 (DMe-DCNQI ) 2,5-dimethyl-N,N′-dicyanoquinonediimine, or DM) charge-transfer salt is a promising material for production by photolithography as it displays a unique photoinduced change in conduction. Photoproducts (β1 and γ) of Ag(DM) 2 were investigated using the X-ray absorption fine structure (XAFS) technique in order to understand the origin of their conduction properties. In contrast to the metallic conduction exhibited by a pristine sample (R), β1 is a semiconductor, whereas γ is an insulator, even though the original Ag(DM) 2 composition is maintained in both the β1 and the γ forms. A redox mechanism has been postulated to explain the photoinduced change in conduction. However, measurement of the Ag L 3edge XANES (X-ray absorption near-edge structure) did not provide any evidence of electron transfer from the DM radical anion to the Ag cation in the β1 and γ products. Ag K-edge extended X-ray absorption fine structure (EXAFS) data demonstrated that β1 is a mixture of the original pristine R phase and a newly found R′ phase, which has a shorter bond distance between the Ag cations and the N atoms of DM molecules. The conduction electrons remain in the DM column of R and R′, but the domain boundaries between R and R′ present an activation barrier for the conduction electrons to cross these boundaries, which provides a rationale for the semiconductive behavior of β1. The Ag K-edge EXAFS results showed that the γ photoproduct has a different local structure from R, with a shorter distance and smaller coordination number of the Ag-N bond. The DM radical anions in the γ compound form covalent bonds between themselves, resulting in a loss of the columnar structure. The complex local structure around Ag cations explains the insulating behavior of the γ compound.

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Variation of electronic phases in (R1R2DCNQI)2Ag: systematic change of the one-dimensional band by chemical substitution of R1 and R2

Cited by 10 publications

References 7 publications

Photochemical modification of magnetic properties in organic low-dimensional conductors

Photochemical modification of magnetic properties in organic low-dimensional conductors

Molecular conductors containing photoreactive species

Origin of Photochemical Modification of the Resistivity of Ag(DMe-DCNQI)₂ Studied by X-ray Absorption Fine Structure

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Variation of electronic phases in (R1R2DCNQI)2Ag: systematic change of the one-dimensional band by chemical substitution of R1 and R2

Cited by 10 publications

References 7 publications

Photochemical modification of magnetic properties in organic low-dimensional conductors

Photochemical modification of magnetic properties in organic low-dimensional conductors

Molecular conductors containing photoreactive species

Origin of Photochemical Modification of the Resistivity of Ag(DMe-DCNQI)2 Studied by X-ray Absorption Fine Structure

Contact Info

Product

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Origin of Photochemical Modification of the Resistivity of Ag(DMe-DCNQI)₂ Studied by X-ray Absorption Fine Structure