Room-temperature phosphorescent materials that emit light in the visible (red, green, and blue; from 400 to 700 nm) have been a major focus of research and development during the past decades, due to their applications in organic light-emitting diodes (OLEDs), light-emitting electrochemical cells, photovoltaic cells, chemical sensors, and bio-imaging. In recent years, near-infrared (NIR) phosphorescence beyond the visible region (700–2500 nm) has emerged as a new, promising, and challenging research field with potential applications toward NIR OLEDs, telecommunications, night vision-readable displays. Moreover, NIR phosphorescence holds promise for in vivo imaging, because cells and tissues exhibit little absorption and auto-fluorescence in this spectral region. This review describes the overall progress made in the past ten years on NIR phosphorescent transition-metal complexes including Cu(I), Cu(II), Cr(III), Re(I), Re(III), Ru(II), Os(II), Ir(III), Pt(II), Pd(II), Au(I), and Au(III) complexes, with a primary focus on material design complemented with a selection of optical, electronic, sensory, and biologic applications. A critical comparison of various NIR phosphorescent materials reported in the literature and a blueprint for future development in this field are also provided.

Near-infrared phosphorescence: materials and applications

A review of computational studies of magnetically induced current density susceptibilities in molecules and their relation to experiments is presented. The history of the investigation of magnetically induced current densities and ring currents in molecules is briefly covered. The theoretical development of relativistic and nonrelativistic computational approaches for computing current densities in closed-shell and open-shell molecules is discussed and different state of the art methods to interpret calculated current densities are reviewed. Numerical integration approaches to assess global, semilocal, and local aromatic properties of multiring molecules are presented and demonstrated on free-base trans-porphyrin. We show that numerical integration of the current density combined with guiding visualization techniques of the current flow is a powerful tool for studies of the aromatic character of complicated molecular structures such as annelated aromatic and antiaromatic rings. Representative applications are reported illustrating the importance of careful current density studies for organic and inorganic chemistry. The applications include calculations of current densities and current strengths for aromatic, antiaromatic, and nonaromatic molecules of different kind. Current densities in spherical, cylindrical, tetrahedral, toroidal, and Mobius-twisted molecules are discussed. The aromatic character, current pathways, and current strengths of porphyrins are briefly highlighted. Aromatic properties of inorganic molecules are assessed based on current density calculations. Current strengths as a noninvasive tool to determine strengths of hydrogen bonds are discussed. WIREs Comput Mol Sci 2016, 6:639–678. doi: 10.1002/wcms.1270

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Calculations of magnetically induced current densities: theory and applications

A novel sandwich-type tris(phthalocyaninato) europium triple-decker complex bearing peripheral electron-withdrawing groups (see center of figure) is used to fabricate a field-effect transistor by the quasi-Langmuir-Schaefer method. The air-stable, single-component ambipolar OFET device displays the best carrier properties of a device fabricated by solution processing of a single phthalocyanine derivative so far, which makes the complex very promising for applications in nanoelectronics.

High-Performance Air-Stable Ambipolar Organic Field-Effect Transistor Based on Tris(phthalocyaninato) Europium(III)

Recent advances in phthalocyanines for chemical sensor, non-linear optics (NLO) and energy storage applications

This Communication details the implementation of a new concept for the design of high-performance optoelectronic materials: three-dimensional (3D) graphene nanostructures. This general strategy is showcased through the synthesis of a three-bladed propeller nanostructure resulting from the coupling and fusion of a central triptycene hub and helical graphene nanoribbons. Importantly, these 3D graphene nanostructures show remarkable new properties that are distinct from the substituent parts. For example, the larger nanostructures show an enhancement in absorption and decreased contact resistance in optoelectronic devices. To show these enhanced properties in a device setting, the nanostructures were utilized as the electron-extracting layers in perovskite solar cells. The largest of these nanostructures achieved a PCE of 18.0%, which is one of the highest values reported for non-fullerene electron-extracting layers.

Three-Dimensional Graphene Nanostructures.

Various functional phthalocyanines as well as their tetrapyrrole analogs, porphyrins, have been extensively studied as organic semiconductors since the first report of organic field effect transistors (OFETs) in 1986. The large conjugated π system, excellent photoelectric characteristics, intriguing and unique optical properties, high thermal and chemical stability, and most importantly the easy functionalization of phthalocyanines render them ideal organic semiconductor materials as active layers for OFETs. In this chapter, the semiconducting properties of monomeric phthalocyanines as well as monomeric porphyrins, bis(phthalocyaninato) rare earth double-deckers, and tris(phthalocyaninato) rare earth triple-deckers in terms of their semiconducting nature (p-type, n-type, or ambipolar), carrier mobility, and current modulation reported in the past two decades have been summarized. Theoretical studies toward understanding the relationship between molecular structures as well as molecular electronic structures of phthalocyanines and their semiconducting properties have also been included.

Organic Semiconductors of Phthalocyanine Compounds for Field Effect Transistors (FETs)

To investigate the effect of axially coordinated ligand(s) on the semidconducting properties of metal phthalocyanine complexes, density functional theory (DFT) calculations were carried out in terms of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy, ionization energy (IE), electronic affinity (EA), and reorganization energy (λ) of F2SnPc, Cl2SnPc, I2SnPc, OSnPc, OVPc, and Cl2TiPc. For the purpose of comparative studies, calculation on SnPc without axially coordinated ligand has also been conducted. The electronic couplings (V) and the charge transfer mobilities for the electron of metal phthalocyanine compounds with reported single crystal structures for Cl2SnPc, I2SnPc, and Cl2TiPc are also calculated. Comparison of the calculated results of SnPc with F2SnPc, Cl2SnPc, I2SnPc, and OSnPc indicates that introduction of axially coordinated ligand(s) obviously lowers the HOMO and LUMO energies of metal phthalocyanine complexes but does not change their ener...

Density functional theory study on the semiconducting properties of metal phthalocyanine compounds: effect of axially coordinated ligand.

The three-unit homoaromatic electron-delocalizing nature of the benzo-fused tetra(triptycene)porphyrins (TTPs) with a three-dimensional conjugated model is clarified using density functional theory studies. Due to the electron delocalization, the unidirectional photon-induced current of this kind of TTP molecular skeleton with a highest efficiency of about 90% in the range between 350 and 500 nm gives them great potential as efficient solar antenna collectors. In addition, their active triptycene cups fused at the central porphyrin core render possible potential application in host-guest chemistry.

A Special Conjugated Model around sp3 Carbon Atoms: Density Functional Theory Study on the Homoaromatic Electron Delocalization and Applications of Benzo‐Fused Tetra(triptycene)porphyrins

Xue Cai

Papers

Organic Semiconductors of Phthalocyanine Compounds for Field Effect Transistors (FETs)

Density functional theory study on the semiconducting properties of metal phthalocyanine compounds: effect of axially coordinated ligand.

A Special Conjugated Model around sp3 Carbon Atoms: Density Functional Theory Study on the Homoaromatic Electron Delocalization and Applications of Benzo‐Fused Tetra(triptycene)porphyrins