Room temperature formation of Cu3Se2 by solid-state reaction between α-Cu2Se and α-CuSe

Upon being brought into contact with each other, α-Cu₂Se and α-CuSe pellets reacted entirely forming Cu₃Se₂ at room temperature. After 10 days, the reaction was almost completed. Weight measurements revealed that copper atoms migrated from α-Cu₂Se to α-CuSe. Solid-state reactions were also observed in the (α-Cu₂Se+Cu₃Se₂) and (α-Cu₂Se+CuS) systems, but not in the (Cu₃Se₂+α-CuSe), (Cu₂S+CuS) and (α-CuSe+Cu₂S) systems. Therefore, the high ionic conductivity of copper ions in α- and β-Cu₂Se is considered to be responsible for the solid-state reactions observed in these systems.     

Thermische Zersetzung von CuInSe2, LiInSe2 und LiInTe2

The thermal decompositions of CuInSe₂, LiInSe₂ and LiInTe₂ in vacuum at high temperatures were studied by using TG/DTG coupled with mass spectrometry. For CuInSe₂, two steps were found to be significant. Up to 1000 °C Se₂ and In₂Se evaporate, followed later by Cu₂Se. The Li-containing compounds show similar behaviour. However, Li⁺ was already detected during the first step. Obviously, Li₂Se dissociates more readily than Cu₂Se. No Cu⁺ species were detected up to the complete evaporation of CuInSe₂.     

Structural investigation of the Cu2Se-In2Se3-Ga2Se3 phase diagram, X-ray photoemission and optical properties of the Cu1−z(In0.5Ga0.5)1+z/3Se2 compounds

Structures of compounds in the Cu₂Se-In₂Se₃-Ga₂Se₃ system have been investigated through X-ray diffraction. Single crystal structure studies for the so-called stoichiometric compounds Cu(In,Ga)Se₂ (CIGSe) confirm that the chalcopyrite structure (space group I4¯2d) is very flexible and can adapt itself to the substitution of Ga for In. On the other hand a structure modification is evidenced in the Cu_1−z(In_0.5Ga_0.5)_1+z/3Se₂ series when the copper vacancy ratio (z) increases; the chalcopyrite structure turns to a modified-stannite structure (I4¯2m) when z≥0.26. There is a continuous evolution of the structure from Cu_0.74(In_0.5Ga_0.5)_1.09Se₂ to Cu_0.25(In_0.5Ga_0.5)_1.25Se₂ ((i.e. Cu(In_0.5Ga_0.5)₅Se₈), including Cu_0.4(In_0.5Ga_0.5)_1.2Se₂ (i.e. Cu(In_0.5Ga_0.5)₃Se₅). From this single crystal structural investigation, it is definitively clear that no ordered vacancy compound exists in that series. X-ray photoemission spectroscopy study shows for the first time that the surface of powdered Cu_1−z(In_0.5Ga_0.5)_1+z/3Se₂ compounds (z≠0) is more copper-poor than the bulk. The same result has often been observed on CIGSe thin films material for photovoltaic applications. In addition, optical band gaps of these non-stoichiometric compounds increase from 1.2 to 1.4 eV when z varies from 0 to 0.75.     

Electrodeposition of CuInSe2 films by an alternating double-potentiostatic method using nearly neutral electrolytes

One step electrodeposition with an alternating double-potentiostatic(DPSED) program was used to prepare CuInSe₂ thin films in nearly neutral aqueous electrolytes with sodium citrate complex. Linear sweep voltammetry(LSV) was measured to probe voltammetric properties of electrolytes with respect to Cu, In and Se individual precursor and their mixed solutions. Compositional and structural characteristics of the as-deposited and annealed films at 400 °C in Ar atmosphere for 0.5 h were analyzed by XRD and XPS. The results showed that reduction of Cu²⁺ to Cu⁺ at one potential point of ?800 mV and subsequently formation of CuIn alloy as well as metal In and amorphous Se at the other potential point of ?1400 mV were responsible for synthesis of CISe chalcopyrite. Composition self-regulation made DPSED films have three elements co-deposition and more uniform element distribution, which promoted chalcopyrite CISe formation.     

离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Disordered La3Cu4.88Se7

The crystal structure of copper(I) lanthanum selenide, La₃Cu_4.88Se₇, obtained from the La₂Se₃–Cu₂Se quasi‐binary system, has been investigated using X‐ray single‐crystal diffraction. The positions of the La and Se atoms are ordered and lie on mirror planes, whereas all positions for the Cu atoms are partially occupied. The crystal is built from edge‐sharing [LaSe₆] and [LaSe₇] polyhedra. The five positions for the Cu atoms determine an ionic diffusion pathway in the structure.     

A Directed Route to Colloidal Nanoparticle Synthesis of the Copper Selenophosphate Cu3PSe4

The first colloidal nanoparticle synthesis of the copper selenophosphate Cu₃PSe₄, a promising new material for photovoltaics, is reported. Because the formation of binary copper selenide impurities seemed to form more readily, two approaches were developed to install phosphorus bonds directly: 1) the synthesis of molecular P₄Se₃ and subsequent reaction with a copper precursor, (P‐Se)+Cu, and 2) the synthesis of copper phosphide, Cu₃P, nanoparticles and subsequent reaction with a selenium precursor, (Cu‐P)+Se. The isolation and purification of Cu₃P nanoparticles and subsequent selenization yielded phase‐pure Cu₃PSe₄. Solvent effects and Se precursor reactivities were elucidated and were key to understanding the final reaction conditions.     

Tyrrellite,Cu(Co0.68Ni0.32)2Se4, isostructural with spinel

Tyrrellite, a naturally occurring Co–Ni–Cu selenide, has been studied by single‐crystal X‐ray diffraction. It possesses the normal spinel‐type structure, with Cu occupying the tetrahedral site and (Co+Ni) the octahedral site. The average Cu—Se distance of 2.3688 (2) Å is close to that of 2.3703 (8) Å in CuCr₂Se₄, whereas the average (Co+Ni)—Se distance of 2.3840 (1) Å appears to be slightly shorter than most octahedral Co—Se or Ni—Se distances (∼2.40–2.50 Å) in other selenides. The refined structure provides a basis for a redefinition of the ideal chemical formula of tyrrellite, which should be Cu(Co,Ni)₂Se₄, rather than the previously suggested (Cu,Co,Ni)₃Se₄.     

Dynamic analysis on metal selenide electrodeposition

Based on the basic principles of kinetics and some reasonable assumptions about the electrodeposition process, a dynamic model for metal selenide electrodeposition (kink site selected model) was constructed. This model is of universal significance in realizing the compositional prediction and dynamic behavior analysis of deposited films for different main salt concentration ratios and was applied to the ternary Cu–In–Se system. For CuInSe₂ electrodeposition, in the Cu–Se system, the co-deposition of Cu and Se can be carried out within a large range of main salt concentration ratio; in the Cu–In system, the mole fraction of Cu in deposited thin films is always higher than that of Cu²⁺ in electrolyte, while in the In–Se system, the co-deposition of In and Se can be achieved only when the In³⁺ concentration is much higher than the H₂SeO₃ concentration. As for the compositional estimation of CuInSe₂, the predictive results of our dynamic model agree well with the experimental data. It is then found that by correcting the difference of kink site selectivity constants caused by the change of deposition potential, the error of the predictive results can be reduced.     

Monoclinic Cu2Se3Sn

A previously unknown modification of dicopper(I) triselenostannate(IV), Cu₂Se₃Sn, has been obtained from the Cu₂Se–SnSe₂ quasi‐binary system and investigated using X‐ray single‐crystal diffraction. The Se atoms are stacked in a closest‐packed arrangement with the layers in the sequence ABC. The Cu atoms occupy one‐third of the tetrahedral interstices, whereas the Sn atoms are located in one‐sixth of the tetrahedral interstices. All the atoms occupy general positions. The structure possesses pseudo‐inversion symmetry. The Cu₂Se₃Sn structure investigated in this paper (96 atoms per unit cell, ordered distribution of Cu and Sn over 12 cation positions) is a superstructure of the reported cubic (eight atoms per unit cell, random distribution of Cu and Sn over one cation position) and monoclinic (24 atoms per unit cell, ordered distribution of Cu and Sn over three cation positions) modifications.     

Compounds in the system Cu2SeAs2Se3

The phase diagram Cu₂SeAs₂Se₃ was investigated by thermal and X-ray methods. Cu₂Se has a limited solubility for As₂Se₃ (5 mole% at 769 K). The stoichiometric compound Cu₃AsSe₃ exists between 696 and 769 K. Cu₄As₂Se₅, a phase at 66.6 mole% Cu₂Se, decomposes peritectically at 746 K. The narrow homogeneity range (4 mole% at 683 K) extends far into the ternary space. CuAsSe₂ also decomposes peritectically at 683 K. A degenerated eutectic between CuAsSe₂ and As₂Se₃ was found at 641 K. Single crystals of Cu₄As₂Se₅ were grown in a salt melt. A metastable modification of the high-temperature phase Cu₃AsSe₃ can be obtained by quenching. Cu₄As₂Se₅ (space group R3, lattice constants a = 1404.0(1) pm, c = 960.2(1) pm), Cu₆As₄Se₉, obtained by Cambi and Elli, and Cu₇As₆Se₁₃ of Takeuchi and Horiuchi are different versions of a sphalerite-type compound with a broad homogeneity range in the system CuAsSe. CuAsSe₂ is possibly monoclinic with lattice parameters of a = 946.5(1) pm, b = 1229.3(1) pm, c = 511.7(1) pm, and β = 98.546(4)°. The enthalpy of mixing of Cu₂Se and As₂Se₃ in the liquid state is endothermic.     

Bis­[bis(N,N‐diethyl‐1,1‐di­seleno­car­bam­ato)copper(II)], [Cu(Se2CNEt2)2]2

The title centrosymmetric Cu^II binuclear complex, bis(μ‐N,N‐diethyl‐1,1‐di­seleno­carbamato‐Se,Se′:Se)­bis­[(N,N‐diethyl‐1,1‐di­seleno­carbamato‐Se,Se′)copper(II)], [Cu(Se₂CNEt₂)₂]₂ or [Cu₂(C₅H₁₀NSe₂)₄], is built from two symmetry‐related [Cu{Se₂CN(Et)₂}₂] units by pairs of Cu—Se bonds. The coordination geometry at the unique Cu atom is distorted square pyramidal, with Cu—Se distances in the range 2.4091 (11)—2.9095 (10) Å.     

The superstructure of KCuCe2Se6 due to ordering of copper cations

The quaternary compound KCuCe₂Se₆ was obtained as black needlelike crystals by reacting a mixture of K₂Se, Cu, Ce and Se in a 2:1:1:8 ratio at 450 °C. The compound crystallizes in the orthorhombic space group Fddd with a = 8.5907(5), b = 11.3962(8) and c = 44.490(3) Å which is a superstructure of the already published structure of KCuCe₂Se₆ which was described in space group Immm. The Ce³⁺ ions are in bicapped distorted trigonal prismatic coordination of Se atoms and the Cu⁺ ions are in tetrahedral environment. The prisms are connected via triangular faces forming rods parallel to the crystallographic a axis. These rods are joined by one capping Se atom and one Se center of the triangular faces thus leading to the formation of anionic layers [CuCe₂Se₆]_n^nȒ within the ab plane. The Cu⁺ ions occupy only one half of the tetrahedral sites in an ordered fashion in contrast to the statistical occupation reported for the substructure. The charge balancing K⁺ ions are located between the anionic layers.     

Spinelle mit substituierten Nichtmetallteilgittern. IV. Rötgenographische Untersuchung der Systeme CuCr2(S1−xSex)4 und CuCr2(Se1−xTex)4

Spinels with substituted Nonmetal Sublattices. IV. CuCr₂(S_1?xSe_x)₄ and CuCr₂(Se_1?xTe_x)₄ Polycrystalline samples of the spinel system CuCr₂(S_1?xSe_x)₄ have been prepared with 0 ≤ x ≤ 1. We found that in the spinel system CuCr₂(Se_1?xTe_x)₄ no solid solution is existent in the range 0.01 ≤ x ≤ 0.70. When S is substituted by Se and Se by Te the lattice constants increase linearely by 0.52 Å and 0.81 Å respectively. The anion-sublattice shows random distribution of the chalcogen atoms, the chalcogen parameters u are constant in the system CuCr₂(S_1?xSe_x)₄ with a mean value of u = 0.382₉. The calculated anion-cation-distances lead to a covalent tetrahedral radius r_Cu = 1.23 Å. This radius is in agreement with the radius r_Cu = 1.22 Å of Cu spinels with Cu in the valence +1.     

Sb‐Triggered β‐to‐α Transition: Solvothermal Synthesis of Metastable α‐Cu2Se

Control over phase stabilities during synthesis processes is of great importance for both fundamental studies and practical applications. We describe herein a facile strategy for the synthesis of Cu₂Se with phase selectivity through a simple solvothermal method. In the presence and absence of SbCl₃, monoclinic α‐Cu₂Se and cubic β‐Cu₂Se can be synthesized, respectively. The formation of α‐Cu₂Se requires optimization of the Cu/Se molar ratio in the starting reagents, the reaction temperature, as well as the timing for the addition of SbCl₃. Differential scanning calorimetry of the synthesized α‐Cu₂Se has shown that a part of it undergoes a phase transition to β‐Cu₂Se at 135 °C, and that this phase transition is irreversible on cooling to ambient temperature. Kinetic studies have revealed that in the presence of Sb species the kinetically favored β‐Cu₂Se transforms to the thermodynamically favored α‐Cu₂Se. In this β‐to‐α phase transition process, the distribution of Cu ions in β‐Cu₂Se, as determined by the Cu/Se ratio and temperature, is likely to play a crucial role.     

Effects of Mn substitution on the structure and properties of chalcopyrite-type CuInSe2

Mn-doped CuInSe₂ compounds (CuIn_1−xMn_xSe₂, x=0.0125–0.20 and Cu_1−yIn_1−yMn_2ySe₂, 2y=0.0125–0.60) were synthesized by high-temperature solid-state reactions. Single phase materials with chalcopyrite structure persist up to 0.10 and 0.20 doping for CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂, respectively. The chalcopyrite and sphalerite phases co-exist in the Cu_1−yIn_1−yMn_2ySe₂ system for 2y=0.25–0.50. Attempts to introduce greater manganese content, x=0.15–0.20 for CuIn_1−xMn_xSe₂ and 2y=0.60 for Cu_1−yIn_1−yMn_2ySe₂, result in partial phase segregation. For the single-phase samples, the lattice parameters of both systems increase linearly with manganese concentration and thus follow Vegard's law. The temperature of the chalcopyrite–sphalerite phase transition is decreased by manganese substitution for all single-phase samples. The bandgap of the materials remains around 0.9 eV. Additionally, the Mn-doped CuInSe₂ compounds display paramagnetic behavior, whereas pure CuInSe₂ is diamagnetic at 5–300 K. All the CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂ compounds with chalcopyrite structure show antiferromagnetic coupling and measured effective magnetic moments up to 5.8 μ_B/Mn.     

Electrochemical growth of CuInSe<Subscript>2</Subscript> thin film on different substrates from alkaline medium. Characterization of the films

The simultaneous electrodeposition of the system Cu–In–Se was investigated. The study was carried out at pH 8.5 using diethylentriamine as complexing agent for the Cu⁺² ion. The synthesis of CuInSe₂ semiconductor thin films was carried out by electrodeposition on different substrates [indium–tin oxide (ITO) on glass, aluminum and type 304 steel]. The simultaneous codeposition of the Cu, In, and Se was achieved by constant potential electrolysis technique in aqueous solutions containing the elements that conform this material. The deposits of CuInSe₂ were about 4 μm thick, which is thick enough for the photovoltaic effect to take place. The as-deposited films were characterized by atomic emission spectroscopy with inductive coupling plasm (AES-ICP) and scanning electronic microscopy (SEM). Annealed films were characterized X-ray diffraction, optical NIR spectroscopy, and photoelectrochemical studies The films were obtained with a well-defined composition, very close to the expected one. Homogeneous deposit with chalcopyrite structure was produced. A In₂O₃ phase was also observed. Annealing of the film improved the crystallinity of the films. Good photo response, an appropriate absorption coefficient, and a band gap of 1.09 eV were obtained.     

Synthese und Strukturen neuer selenido‐ und selenolatoverbrückter Kupfercluster: [Cu38Se13(SePh)12(dppb)6] (1), [Cu(dppp)2][Cu25Se4(SePh)18(dppp)2] (2), [Cu36Se5(SePh)26(dppa)4] (3), [Cu58Se16(SePh)24(dppa)6] (4) und [Cu3(SeMes)3(dppm)] (5)

Syntheses and Crystal Structures of new Selenido‐ and Selenolato‐bridged Copper Clusters: [Cu₃₈Se₁₃(SePh)₁₂(dppb)₆] (1), [Cu(dppp)₂][Cu₂₅Se₄(SePh)₁₈(dppp)₂] (2), [Cu₃₆Se₅(SePh)₂₆(dppa)₄] (3), [Cu₅₈Se₁₆(SePh)₂₄(dppa)₆] (4), and [Cu₃(SeMes)₃(dppm)] (5) The reactions of copper(I) chloride or copper(I) acetate with monodentate phosphine ligands (PR₃; R = organic group) and Se(SiMe₃)₂ have already lead to the formation of CuSe clusters with up to 146 copper and 73 selenium atoms. If the starting materials and the bidentate phosphine ligands (Ph₂P–(CH₂)_n–PPh₂, n = 1: dppm, n = 3: dppp, n = 4: dppb; Ph₂P–C≡C–PPh₂: dppa) and silylated chalcogen derivates are changed (RSeSiMe₃; R = Ph, Mes) a series of new CuSe clusters can be synthesized. From single crystal X‐ray structure analysis one can characterise [Cu₃₈Se₁₃(SePh)₁₂(dppb)₆] ( 1 ), [Cu(dppp)₂] · [Cu₂₅Se₄(SePh)₁₈(dppp)₂] ( 2 ), [Cu₃₆Se₅(SePh)₂₆(dppa)₄] ( 3 ), [Cu₅₈Se₁₆(SePh)₂₄(dppa)₆] ( 4 ) and [Cu₃(SeMes)₃(dppm)] ( 5 ). In this new class of CuSe clusters, compounds 1 and 4 possess a spherical cluster skeleton, wheras 2 and 3 have a layered cluster core.     

离子液体电沉积CuIn_xGa_(1-x)Se_2薄膜(英文)

采用循环伏安法(CV)对离子液体Reline中三元CuCl2+InCl3+SeCl4体系和四元CuCl2+InCl3+GaCl3+SeCl4体系的电化学行为进行了研究。研究表明,In3+并入三元CIS(Cu-In-Se)薄膜体系和Ga3+并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径:一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu1.00In0.78Ga0.27Se2.13的薄膜。     

Cu(I) and Ag(I) complexes of chalcogenide derivatives of the organometallic ligand dppf and the dppa analogue

New Cu(I) and Ag(I) complexes were prepared by reaction of [M(NCCH₃)₄][X] (M = Cu or Ag; X = BF₄ or PF₆) with the bidentate chalcogenide ligands Ph₂P(E)NHP(E)Ph₂ (E = S, S₂dppa; E = Se, Se₂dppa), and dpspf (1,1′-bis(diphenylselenophosphoryl)ferrocene). Copper and silver behaved differently. While three molecules of either S₂dppa and Se₂dppa bind to a distorted tetrahedral Cu₄ cluster, with deprotonation of the ligand, 1:2 complexes of the neutral ligands are formed with Ag(I), with a tetrahedral coordination of the metal. The [Cu₄{Ph₂P(Se)NP(Se)Ph₂}₃]⁺ clusters assemble as dimers, held together by weak Se?Se distances interactions. Another dimer was observed for the [Ag(dpspf)]⁺ cation, with two short Ag?Se distances. DFT and MP2 calculations indicated the presence of attracting interactions, reflected in positive Mayer indices (MI). The electrochemistry study of this species showed that both oxidation and reduction took place at silver.