A broad organic–inorganic series of hybrid metal iodide perovskites with the general formulation AMI3, where A is the methylammonium (CH3NH3+) or formamidinium (HC(NH2)2+) cation and M is Sn (1 and 2) or Pb (3 and 4) are reported. The compounds have been prepared through a variety of synthetic approaches, and the nature of the resulting materials is discussed in terms of their thermal stability and optical and electronic properties. We find that the chemical and physical properties of these materials strongly depend on the preparation method. Single crystal X-ray diffraction analysis of 1–4 classifies the compounds in the perovskite structural family. Structural phase transitions were observed and investigated by temperature-dependent single crystal X-ray diffraction in the 100–400 K range. The charge transport properties of the materials are discussed in conjunction with diffuse reflectance studies in the mid-IR region that display characteristic absorption features. Temperature-dependent studies show a ...

Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties.

Since the discovery of highly conducting polyacetylene by Shirakawa, MacDiarmid, and Heeger in 1977, π-conjugated systems have attracted much attention as futuristic materials for the development and production of the next generation of electronics, that is, organic electronics. Conceptually, organic electronics are quite different from conventional inorganic solid state electronics because the structural versatility of organic semiconductors allows for the incorporation of functionality by molecular design. This versatility leads to a new era in the design of electronic devices. To date, the great number of π-conjugated semiconducting materials that have either been discovered or synthesized generate an exciting library of π-conjugated systems for use in organic electronics. 11 However, some key challenges for further advancement remain: the low mobility and stability of organic semiconductors, the lack of knowledge regarding structure property relationships for understanding the fundamental chemical aspects behind the structural design, and realization of desired properties. Organic field-effect transistors (OFETs) are a kind of device consisting of an organic semiconducting layer, a gate insulator layer, and three terminals (drain, source, and gate electrodes). OFETs are not only essential building blocks for the next generation of cheap and flexible organic circuits, but they also provide an important insight into the charge transport of πconjugated systems. Therefore, they act as strong tools for the exploration of the structure property relationships of πconjugated systems, such as parameters of field-effect mobility (μ, the drift velocity of carriers under unit electric field), current on/off ratio (the ratio of the maximum on-state current to the minimum off-state current), and threshold voltage (the minimum gate voltage that is required to turn on the transistor). 17 Since the discovery of OFETs in the 1980s, they have attracted much attention. Research onOFETs includes the discovery, design, and synthesis of π-conjugated systems for OFETs, device optimization, development of applications in radio frequency identification (RFID) tags, flexible displays, electronic papers, sensors, and so forth. It is beyond the scope of this review to cover all aspects of π-conjugated systems; hence, our focus will be on the performance analysis of π-conjugated systems in OFETs. This should make it possible to extract information regarding the fundamental merit of semiconducting π-conjugated materials and capture what is needed for newmaterials and what is the synthesis orientation of newπ-conjugated systems. In fact, for a new science with many practical applications, the field of organic electronics is progressing extremely rapidly. For example, using “organic field effect transistor” or “organic field effect transistors” as the query keywords to search the Web of Science citation database, it is possible to show the distribution of papers over recent years as shown in Figure 1A. It is very clear

Semiconducting π-conjugated systems in field-effect transistors: a material odyssey of organic electronics.

We fabricated a perovskite solar cell that uses a double layer of mesoporous TiO2 and ZrO2 as a scaffold infiltrated with perovskite and does not require a hole-conducting layer. The perovskite was produced by drop-casting a solution of PbI2, methylammonium (MA) iodide, and 5-ammoniumvaleric acid (5-AVA) iodide through a porous carbon film. The 5-AVA templating created mixed-cation perovskite (5-AVA)x(MA)1- xPbI3 crystals with lower defect concentration and better pore filling as well as more complete contact with the TiO2 scaffold, resulting in a longer exciton lifetime and a higher quantum yield for photoinduced charge separation as compared to MAPbI3. The cell achieved a certified power conversion efficiency of 12.8% and was stable for >1000 hours in ambient air under full sunlight.

https://science.sciencemag.org/content/sci/345/6194/295.full.pdf

A hole-conductor-free, fully printable mesoscopic perovskite solar cell with high stability

/pdf/metal-organic-frameworks-and-self-assembled-supramolecular-2xs948xxr9.pdf

Metal–Organic Frameworks and Self-Assembled Supramolecular Coordination Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal–Organic Materials

Although known since the late 19th century, organic–inorganic perovskites have recently received extraordinary research community attention because of their unique physical properties, which make them promising candidates for application in photovoltaic (PV) and related optoelectronic devices. This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovskite family for electronic, optical, and energy-based applications as well as fundamental research. The concept of a multifunctional organic–inorganic hybrid, in which the organic and inorganic structural components provide intentional, unique, and hopefully synergistic features to the compound, represents an important contemporary target.

Organic–Inorganic Perovskites: Structural Versatility for Functional Materials Design

In the strong orange luminescent material of [Pb(bp4mo)Cl2], two different types of octahedra, namely PbCl4N2 and PbCl4O2, are bridged by the N-oxide-4,4′-bipyridine (bp4mo) ligand, while its protonated form, Hbp4mo+, coordinates to Pb2+ center only with the N-oxide group in [Pb(Hbp4mo)2Cl2](NO3)2. Important relationships between structures and luminescence properties are revealed.

N-oxide-4,4′-bipyridine, a forgotten ligand in coordination chemistry: structure–photoluminescence property relationships in 2D and 1D lead-coordination polymers

Synthesis, characterization and crystal structure of a new copper fluorocarbonate KCu(CO3)F

The zwitterionic 1,1′-bis(4-carboxyphenyl)-4,4′-bipyridinium (bp4pc) has been synthesized and crystals of its hydrated form bp4pc·2H2O and of its protonated reduced form H-bp4pc have been obtained. Upon heating, bp4pc·2H2O undergoes partial dehydration, leading to bp4pc·H2O at 160 °C, together with a color change from yellow (room temperature) to green (140 °C) and finally to brown (160–180 °C). Analysis of bond lengths in the solid state reveals the expected short (d = 1.425 A) and long (d = 1.485 A) C–C central bond lengths in the all-radical salt H-bp4pc and bp4pc·2H2O, respectively, whereas the distance of 1.475 A in bp4pc·H2O does not allow a conclusion to be drawn regarding the presence of radicals in this compound. EPR and solid-state paramagnetic NMR experiments of H-bp4pc and the hydrated zwitterion bp4pc·2H2O at different temperatures, however, show that the color change of the latter upon heating is due to the presence of bipyridinium radicals, the concentration of which, although low, increases with increasing temperature. The nature of the electron donor involved in this thermal-induced electron transfer is not fully understood. Most plausible is the possibility that it is the carboxylate group with an intramolecular electron-transfer process; on the other hand it, cannot be excluded that the electron stems from the water molecule, which decomposes into O2, H+, and e– giving H-bp4pc entities.

/pdf/bipyridinium-bis-carboxylate-radical-based-materials-x-ray-4ppf8rgxwp.pdf

Bipyridinium-bis(carboxylate) Radical Based Materials: X-ray, EPR and Paramagnetic Solid-State NMR Investigations

The syntheses, crystal structures, and thermal properties of five cuprous bromides derived from cystamine, [NH3(CH2)2SS(CH2)2NH3]2+, here denoted by (SS), are reported. Whereas (SS)2Cu4Br8 (1) is a polar tetramer and (SS)2Cu2Br6 (2) consists of [(SS)Cu2Br6]2– dimers, α1-(SS)Cu2Br4 (3), (SS)Cu3Br5 (4), and α2-(SS)Cu2Br4 (5) are polymers; 3 and 5 are one-dimensional and 4 has a corrugated 2D network. All the compounds contain corner-shared tetrahedra with Cu–Br–Cu connections, and in some cases, edge-shared with double bromine bridges. The copper coordination is tetrahedral, either CuBr4 or CuBr3S, except in one case, in which trigonal geometry was encountered. Compounds 1, 2, and 4, which are synthesized at 50 °C, display Cu–S bonds with the cystamine through either one or both sulfur atoms. On the other hand, 3 and 5, which are synthesized at 80 °C, do not have any. There is a high tendency to form hydrogen bonds between the polar ammonium heads of the cystamine with the bromine atoms. The range of phases experienced in this system is related to the bifunctional nature of cystamine, which is characterized by its primary ammonium ends and its disulfide bridge, and to the subtle competition between Br– and S–S ligands towards the CuI ions, which appears to be controllable by temperature. The presence of both chiral M- and P-helicoidal conformers of cystamine in 1–5 results in racemic compounds adopting centrosymmetric structures for 1, 3, 4, and 5 but 2 adopts a noncentrosymmetric structure (P212121) resulting from the coordination of copper ions to one conformer; the other conformer is noncoordinated and acts as the counterion.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Nicolas Mercier

Papers

N-oxide-4,4′-bipyridine, a forgotten ligand in coordination chemistry: structure–photoluminescence property relationships in 2D and 1D lead-coordination polymers

Synthesis, characterization and crystal structure of a new copper fluorocarbonate KCu(CO3)F

Bipyridinium-bis(carboxylate) Radical Based Materials: X-ray, EPR and Paramagnetic Solid-State NMR Investigations

CuI–Br Oligomers and Polymers Involving Cu–S(cystamine) Bonds

Structure and optical properties of KGd(CO3)F2:Eu3+