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Single‐component semiconductors with photoresponse to full solar spectrum are highly desirable to simplify the device structure of commercial photodetectors and to improve solar conversion or photocatalytic efficiency but remain scarce. This work reports bottom‐up photosynthesis of an air‐stable radical semiconductor using BiI3 and a photochromism‐active benzidine derivative as a photosensitive functional motif. This semiconductor shows photoconductivity to full solar spectrum contributed by radical and non‐radical forms of the benzidine derivative. It has also the potential to detect X‐rays because of strong X‐ray absorption coefficient. This finding opens up a new synthetic method for radical semiconductors and may find applications on extending photoresponsive ranges of perovskites, transition metal sulfides, and other materials. [ABSTRACT FROM AUTHOR]

Introduction of photochromic properties into semiconductors confers semiconductors with smart behaviors, color‐related applications, and new modulation approaches. Photochromophores with electron‐transfer (redox) behavior, such as viologen and naphthalene diimide, are ideal functional motifs to design photochromic semiconductors owing to good adaptability to the solid matrix, but their reverse reactions are exclusively realized by the thermal mode, which is slow (in dozens of seconds or longer) and thus significantly hinders real applications in the fields that require high‐speed switching. This study reveals that photoexcitation in the electronic absorption band of the π‐aggregate of viologen cation radicals can successfully trigger reverse electron transfer quickly (in 1 s with a continuous‐wave 808 nm laser at a power density of 5 W cm−2; the photothermal effect is excluded), and the first single‐component all‐optically photochromic semiconductor is accordingly discovered. This discovery breaks through a traditional concept that reverse reactions of viologen compounds can not be triggered by the light, and provides a potential approach to realize all‐optical switch of single‐component photochromic smart semiconductors based on electron‐transfer photochromic functional motifs. [ABSTRACT FROM AUTHOR]

Copper chalcogenides have drawn considerable attention due to their prominent semiconducting properties. A new Cu-containing semiconductor, namely, CsCuS4 (1), was obtained by a halide salt flux method. Its structure featured 1D infinite ∞1 [CuS4] − chains, where the polysulfide anion S42− was relatively rare in Cu chalcogenides. The compound was multifunctional and exhibited significant photocurrent, humidity sensitivity, and proton conductivity properties. Specifically, it exhibits an "on" state photocurrent response of 0.95 μA cm−2 and an "off" state photocurrent response of 0.55 μA cm−2 with good reversibility. The humidity-sensitive resistance in dry air (10% RH) could reach up to six orders of magnitude higher than that in wet air (100% RH). Compound 1 showed an activation energy of 0.19 eV and may have potential electrochemical applications. [ABSTRACT FROM AUTHOR]

A new design strategy through the synergy of Mo(VI)–Mo(V) intervalence charge transfer and π(radical)–π(radical/cation) interactions is proposed to obtain semiconductors with photoresponsive ranges covering the whole UV–SWIR (ultraviolet–shortwave near-infrared; ca. 250–3000 nm) region. With this strategy, a viologen-based molybdate semiconductor with a UV–SWIR photoresponsive range was obtained through UV/X-ray irradiation or thermal annealing. The thermally annealed semiconductor has the highest conversion and the best photocurrent response in the range of 355–2400 nm. [ABSTRACT FROM AUTHOR]

Extending photoresponse ranges of semiconductors to the entire ultraviolet–visible (UV)–shortwave near-infrared (SWIR) region (ca. 200–3000 nm) is highly desirable to reduce complexity and cost of photodetectors or to promote power conversion efficiency of solar cells. The observed up limit of photoresponse for organic-based semiconductors is about 1800 nm, far from covering the UV–SWIR region. Here we develop a cyanide-bridged layer-directed intercalation approach and obtain a series of two viologen-based 2D semiconductors with multispectral photoresponse. In these compounds, infinitely π-stacked redox-active N-methyl bipyridinium cations with near-planar structures are sandwiched by cyanide-bridged MnII–FeIII or ZnII–FeIII layers. Radical–π interactions among the infinitely π-stacked N-methyl bipyridinium components favor the extension of absorption range. Both semiconductors show light/thermo-induced color change with the formation of stable radicals. They have intrinsic photocurrent response in the range of at least 355–2400 nm, which exceeds all reported values for known single-component organic-based semiconductors. Developing new materials with broadband photoresponse is highly desirable for realizing commercial photodetectors with extended detection ranges. Here, the authors report a cyanide-bridged layer-directed intercalation approach to design viologen compounds with enhanced broadband photoresponse. [ABSTRACT FROM AUTHOR]

Breaking the intrinsic rule of semiconductors that conductivity increases with increase of temperature and realizing a dramatic dropping of conductivity at high temperature may arouse new intriguing applications, such as circuit overload or over‐temperature protecting. This goal has now been achieved through T‐type electron‐transfer photochromism of one organic semiconductor assembled by intermolecular cation⋅⋅⋅π interactions. Conductivity of the viologen‐based model semiconductor (H2bipy)(Hox)2 (H2bipy=4,4′‐bipyridin‐1,1′‐dium; ox=oxalate) increased by 2 orders of magnitude after photoinduced electron transfer (a record for photoswitchable organic semiconductors) and generation of radical cation⋅⋅⋅π interactions, and fell by approximately 81 % at 100 °C through reverse electron transfer and degeneration of the radical cation⋅⋅⋅π interactions. The model semiconductor has at least two different electron transfer pathways in the decoloration process. [ABSTRACT FROM AUTHOR]

Superlattice materials offer new opportunities to modify optical and electrical properties of recently emerging 2D materials. The insertion of tetraethylbenzidine (EtDAB) into interlamination of the established 2D PbI2 semiconductor through a mild solution method yielded the first lead iodide superlattice, EtDAB⋅4PbI2 (EtDAB=tetraethylbenzidine), with radical and non‐radical forms. The non‐radical form has a non‐ionic structure that differs from the common ionic structures for inorganic–organic hybrid lead halides. The radical form shows five orders of magnitude greater conductance and broader photoconductive response range (UV/Vis → UV/Vis‐IR), than pure PbI2 and the non‐radical form of the superlattice. Lead the way: The first lead‐iodide superlattice constructed from non‐ionic organic molecules and PbI2 through van der Waals interactions is a new type of inorganic–organic hybrid and has a radical and a non‐radical form. The radical form has an almost five orders of magnitude greater conductivity and broader band photoconductive response than that of the non‐radical form or pure PbI2. [ABSTRACT FROM AUTHOR]

Introduction of the viologen cation, a well-known electron acceptor, into molybdate layers led to a dramatic change in the conductance of the 2D hybrid material in the process of photo-induced or thermo-induced coloration, which provides an alternative approach to manipulate the electronic properties of 2D semiconductors via external optical/thermal stimuli. [ABSTRACT FROM AUTHOR]

A photochromic compound with fast response to Mo-Kα (4 min) and Al-Kα (1 s) X-rays was synthesized using a cluster of high-Z atoms and a flexible viologen zwitterion. The coloration time of 1 s when exposed to soft X-rays is the recorded minimum for X-ray-induced photochromic materials, indicating a potential to detect low-energy X-rays. [ABSTRACT FROM AUTHOR]

We report the exploration of the stabilization effect of the in situ generated N-alkylated DABCO (DABCO = 1,4-diazabicyclo[2.2.2]octane) cation in the family of bromoplumbates and a 1-D bromoplumbate, (Et2DABCO)2n(Pb3Br10)n (1), has been prepared by solvothermal conditions. Optical diffuse reflectance determination shows the band gap of 1 is 3.69 eV, which manifests that 1 is a wide band gap semiconductor. Compared with the band gap of bulk PbBr2 (3.84 eV), 1 exhibits 0.15 eV red shift of absorption edge. While for the reported iodo analogs of this compound, (MPDA)2n(Pb3I10)n and (Et2DABCO)2n(Pb3I10)n, they exhibit 0.53 and 0.47 eV blue shift of the energy gaps compared with the measured value of 2.30 eV for bulk PbI2, respectively. The photoluminescent study of 1 shows that it exhibits a broad emission band centered at 697 nm upon photoexcitation by 345 nm (amount to 3.59 eV). The calculated density of states manifests the theoretical value of the band gap of 1 is 3.422 eV and the origination of photoluminescence can be ascribed to the transition of bonding electrons of Br– anion to the empty orbits of Pb(II) ion. [ABSTRACT FROM AUTHOR]

Electron-transfer (redox) thermochromism was successfully used for switching the conductance of semiconductors, by introducing a thermally active organic component into an inorganic semiconducting framework. A moisture-resistant semiconductor {(MV)2[Pb7Br18]} n (MV2+=methyl viologen cation) has been prepared through an in situ synthetic method for MV2+. It features a rare 3D haloplumbate open framework and unprecedented electron-transfer thermochromic behavior in haloplumbates. The electrical conductivity of this compound dropped significantly after coloration and restored after decoloration, which was satisfactorily explained by valence band XPS and theoretical data. This work not only offers a new approach to modify electrical properties of semiconductors without altering components or structures, but may lead to the development of over-temperature color indicators, circuit overload protectors or photovoltaic materials. [ABSTRACT FROM AUTHOR]

Crystalline nanotube array would create great opportunity for novel electrical application. Herein we report the first example of a metal halide based crystalline nanotube array which is constructed from an unprecedented giant [PbII18I54(I2)9] wheel cluster, as determined by synchrotron Xray diffraction. The electrical properties of the single crystal were studied and the present compound shows typical semiconductivity and highly anisotropic conductivity. [ABSTRACT FROM AUTHOR]

We investigate the impact of different derivatives of 1,4-diazabicyclo[2.2.2]octane on the crystal structures of iodoplumbates by systematically increasing the size of the same organic amine, and present two new 1-D iodoplumbates. Optical studies reveal the semiconductor characteristics of all as-synthesized iodoplumbate hybrids. [ABSTRACT FROM AUTHOR]

Abstract: A novel 3-D inorganic open-framework containing unusual heptanuclear quasi-supertetrahedra, Cd7I12S·3H2O (1), was obtained by hydrothermal reaction and structurally characterized. Optical absorption spectrum reveals that the presence of an optical gap of 2.26eV, indicating that compound 1 is a semiconductor. [Copyright &y& Elsevier]

Copper chalcogenides have drawn considerable attention due to their prominent semiconducting properties. A new Cu-containing semiconductor, namely, CsCuS4 (1), was obtained by a halide salt flux method. Its structure featured 1D infinite ∞1 [CuS4] − chains, where the polysulfide anion S42− was relatively rare in Cu chalcogenides. The compound was multifunctional and exhibited significant photocurrent, humidity sensitivity, and proton conductivity properties. Specifically, it exhibits an "on" state photocurrent response of 0.95 μA cm−2 and an "off" state photocurrent response of 0.55 μA cm−2 with good reversibility. The humidity-sensitive resistance in dry air (10% RH) could reach up to six orders of magnitude higher than that in wet air (100% RH). Compound 1 showed an activation energy of 0.19 eV and may have potential electrochemical applications. [ABSTRACT FROM AUTHOR]

• [Rb 4 Cl][Cd 11 In 9 S 26 ] was a novel noncentrosymmetric salt-inclusion Chalcogenide. • It presents a distinctive [Cd 11 In 9 S 26 ]3 − framework constructed by pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra. • It shows decent phase-matchable SHG response, moderate band gap and high LIDT. [Display omitted] Salt-inclusion chalcogenide is a promising infrared (IR) nonlinear optical (NLO) system for its potential in mitigating the incompatibility between second harmonic generation (SHG) efficiency and laser-induced damage threshold (LIDT). Herein, a new noncentrosymmetric salt-inclusion chalcogenide, [Rb 4 Cl][Cd 11 In 9 S 26 ] (1), was prepared by high-temperature solid-state method. It features a distinctive [Cd 11 In 9 S 26 ]3- host framework composing of pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra, which are rare in known salt-inclusion chalcogenides. Remarkably, compound 1 exhibits a phase-matchable SHG signal (0.23 times that of benchmark AgGaS 2), which mainly originates from the distorted CdS 4 and InS 4 tetrahedra in the host moiety. Moreover, it possesses moderate band gap (2.32 eV) and high LIDT (4.9 ×AgGaS 2). Such high LIDT may due to its small thermal expansion anisotropy. [ABSTRACT FROM AUTHOR]

Abstract: Inorganic–organic hybrids with mixed halo atoms or organically coordinated halometal-complex cations are rare. A series` of haloplumbate hybrids with these structural features, [Cu(phen)2Cl] n (PbCl3) n (phen = 1,10-phenanthroline) (1), [Cu(phen)2Cl] n [PbClI(Cl0.5I0.5)] n (2), and [Cu(phen)2I] n (PbI3) n (3), have been solvothermally synthesized using phen coordinated halocopper(II) complexes as templates and balance cations. Their haloplumbate ions all show 1-D chain structures. Compounds 1–3 feature the hybridization of inorganic–organic hybrids: 1) their absorption edges fall in the range of those of semiconductors, which is typical for bulk lead(II) halides, but show a red shift compared with those of the latter; 2) bulk lead(II) halides are nonluminous upon UV irradiation, but introduction of the phen coordinated halocopper(II) complexes as templates enable the hybrids to emit blue light. Their luminescent intensities gradually decrease with the increase of I content, which indicates the potential to design and syntheses of new luminescent halide materials by means of variation of halo atoms and that iodoplumbates are not good candidates for luminescent materials. [Copyright &y& Elsevier]

Abstract: A new supramolecular complex [Hg6Sb4](InBr6)Br (1) has been prepared by the solid-state reaction of HgBr 2 with elemental In and Sb at 450°C. The crystal structure of 1 features a three-dimensional [Hg6Sb4]4+ framework with cavities of two different sizes occupied by different kinds of guest anions. The bigger cavities are filled with the octahedral InBr6 3− ions, while the smaller cavities trap Br− ions. The optical properties were investigated in terms of the diffuse reflectance and infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is semiconductor, and the optical absorption is mainly originated from the charge transitions from Sb-5p and Br-4p to In-5s and Hg-6s states. [Copyright &y& Elsevier]

Abstract: A new synthetic approach with the advantage of low cost and facile operation, which is characterized by using Hg(CN)2 as starting material, has been successfully established for the preparation of Hg1−X Cd x Te (MCT) materials with different x values, especially the Hg rich MCT. Three new compounds, namely Hg0.90Cd0.10Te (1), Hg0.32Cd0.68Te (2) and Hg0.29Cd0.71Te (3), have been synthesized, respectively. These compounds possess sphalerite structures with the space group F-43m. Their optical properties were investigated in terms of the diffuse reflectance and Fourier transform infrared spectra. Electronic band structures along with density of states (DOS) calculated by DFT method indicate that the present compounds belong to direct semiconductors and their optical absorptions are mainly originated from the charge transitions from Te-5p to Cd-5s and Hg-6s states. [Copyright &y& Elsevier]

Abstract: High-quality single crystals of RbInS2, CsInS2 were isolated from the halide flux as a major phase of the repeated fusion of CaS and In2S3 followed by slow cooling. RbInS2 and CsInS2 are practically isostructural with KInS2. RbInS2: C2/c, a =11.071(6)Å, b =11.068(1)Å, c =15.610(7)Å, β =100.36(3)°, V =1882(2)Å3, Z =16, d x =3.74g/cm3, R =6.38%, R w =6.42%. CsInS2: C2/c, a =11.197(3)Å, b =11.158(3)Å, c =16.358(4)Å, β =99.92(2)°, V =2013(2)Å3, Z =16, d x =4.12g/cm3, R =5.60%, R w =6.20%. The AInS2 (A=Rb, Cs) structure is characterized by double layers of vertex-sharing [In4S10] units that each consists of four [InS4] polyhedra. The charge-balancing alkali-metal cations are stuffed into the channels created by the packing of these anionic [In4S10] blocks. The optical reflectance measurements show a band gap of 3.3eV for RbInS2 and 3.4eV for CsInS2, suggesting that both are semiconductors. [Copyright &y& Elsevier]

Abstract: Two isostructural metal chalcogenides, Hg2Te2Br2 (1) and Hg2Te2I2 (2), were obtained by solid-state reactions and structurally characterized. Compounds 1 and 2 crystallize in the acentric space group P43212 of the tetragonal system with eight formula units in a cell: a=10.2388(9), c=14.480(2)Å, V=1518.0(3)Å3, R 1/wR 2=0.0670/0.1328 for 1 and a=10.711(3), c=15.025(8)Å, V=1724(1)Å3, R 1/wR 2=0.0637/0.1233 for 2. Both compounds are characterized by a three-dimensional (3-D) framework structure, which is composed by interconnected left-handed helices formed by both tetrahedral and trigonal Hg atoms. Optical absorption spectra of 1 and 2 reveal the presence of sharp optical gaps of 2.06 and 1.85eV, respectively, suggesting that both materials are semiconductors. TG-DTA measurements show that both compounds are thermally stable up to 200°C. The composition of both compounds is well confirmed by the semiquantitative microscope analyses. [Copyright &y& Elsevier]

Hg5AsS2I3 is prepared by solid-state reaction of a 3:1:1 molar mixture of Hg2I2, As, and S (pressed pellet, evacuated glass tube; 1. [ABSTRACT FROM AUTHOR]

Red single crystals of the new title compound are prepared by stoichiometric solid state reaction of Hg2Cl2, red P, and Cu (evacuated Pyrex tube, 1. [ABSTRACT FROM AUTHOR]

The new title compound is hydrothermally prepared from a mixture of MgO, TeO2, and H2O (autoclave, 220 °C, 3 d) and characterized by single crystal XRD, UV and IR spectroscopy, and DFT band structure calculations. [ABSTRACT FROM AUTHOR]