The electronic and structural properties of ten heteroleptic [Cu­(NN)­(PP)]+ complexes have been investigated. NN indicates 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (Bphen); each of these ligands is combined with five PP bis-phosphine chelators, i.e., bis­(diphenylphosphino)­methane (dppm), 1,2-bis­(diphenylphosphino)­ethane (dppe), 1,3-bis­(diphenylphosphino)­propane (dppp), 1,2-bis­(diphenylphosphino)­benzene (dppb), and bis­[(2-diphenylphosphino)­phenyl] ether (POP). All complexes are mononuclear, apart from those based on dppm, which are dinuclear. Experimental dataalso taken from the literature and including electrochemical properties, X-ray crystal structures, UV–vis absorption spectra in CH2Cl2, luminescence spectra and lifetimes in solution, in PMMA, and as powdershave been rationalized with the support of density functional theory calculations. Temperature dependent studies (78–358 K) have been performed for selected complexes to assess thermally activated delayed fluorescence. The main findings are (i) dependence of the ground-state geometry on the crystallization conditions, with the same complex often yielding different crystal structures; (ii) simple model compounds with imposed C 2v symmetry ([Cu­(phen)­(PX3)2]+; X = H or CH3) are capable of modeling structural parameters as a function of the P–Cu–P bite angle, which plays a key role in dictating the overall structure of [Cu­(NN)­(PP)]+ complexes; (iii) as the P–Cu–P angle increases, the energy of the metal-to-ligand charge transfer absorption bands linearly increases; (iv) the former correlation does not hold for emission spectra, which are red-shifted for the weaker luminophores; (v) the larger the number of intramolecular π-interactions within the complex in the ground state, the higher the luminescence quantum yield, underpinning a geometry locking effect that limits the structural flattening of the excited state. This work provides a general framework to rationalize the structure–property relationships of [Cu­(NN)­(PP)]+, a class of compounds of increasing relevance for electroluminescent devices, photoredox catalysis, and solar-to-fuels conversion, which so far have been investigated in an unsystematic fashion, eluding a comprehensive understanding.

A series of copper(I) pseudorotaxanes has been prepared from bis[2-(diphenylphosphino)phenyl] ether (POP) and macrocyclic phenanthroline ligands with different ring sizes (m30, m37, and m42). Variable-temperature studies carried out on the resulting [Cu(mXX)(POP)] (mXX = m30, m37, and m42) derivatives have revealed a dynamic conformational equilibrium due to the folding of the macrocyclic ligand. The absorption and luminescence properties of the pseudorotaxanes have been investigated in CHCl. They exhibit metal-to-ligand charge-transfer emission with photoluminescence quantum yields (PLQYs) in the range 20-30%. The smallest system [Cu(m30)(POP)] shows minimal differences in spectral shape and position compared to its analogues, suggesting a slightly distorted coordination environment. PLQY is substantially enhanced in poly(methyl methacrylate) films (∼40-45%). The study of emission spectra and excited-state lifetimes in powder samples as a function of temperature (78-338 K) reveals thermally activated delayed fluorescence, with sizable differences in the singlet-triplet energy gap compared to the reference compound [Cu(dmp)(POP)] (dmp = 2,9-dimethyl-1,10-phenanthroline) and within the pseudorotaxane series. The system with the largest ring ([Cu(m42)(POP)]) has been tested as emissive material in OLEDs and affords bright green devices with higher luminance and greater stability compared to [Cu(dmp)(POP)], which lacks the macrocyclic ring. This highlights the importance of structural factors in the stability of electroluminescent devices based on Cu(I) materials.

Additive manufacturing is a layer-by-layer strategy enabling the advanced design and fabrication of complex 3D objects and structures, overcoming geometry limitations and reducing waste production compared to conventional technologies. Among various additive manufacturing technologies, digital light processing (DLP), is an additive manufacturing technology used to print photopolymer parts, using a projected light source to cure an entire layer at once. Initially developed for pure resins, recent advances have demonstrated the potential of DLP in the polymerization of ceramic and metal-loaded suspensions, enabling the fabrication of ceramic and metal components after proper debinding and sintering. Such flexibility increases the potential of DLP for different applications, ranging from dental implants and bone scaffolds to smart biomaterials for soft robotics, smart wearables, and microfluidic devices. The review provides an overview of DLP technology and its recent advances; specifically, the review covers the photopolymer properties, the ceramic and metallic feedstock preparation, and the light-matter interaction mechanism underpinning the printing and post-processing steps. Finally, a description of the current application is provided and complemented with future perspectives.

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The transfer of chemical vapor deposited graphene is a crucial process, which can affect the quality of the transferred films and compromise their application in devices. Finding a robust and intrinsically clean material capable of easing the transfer of graphene without interfering with its properties remains a challenge. We here propose the use of an organic compound, cyclododecane, as a transfer material. This material can be easily spin coated on graphene and assist the transfer, leaving no residues and requiring no further removal processes. The effectiveness of this transfer method for few-layer graphene on a large area was evaluated and confirmed by microscopy, Raman spectroscopy, x-ray photoemission spectroscopy, and four-point probe measurements. Schottky-barrier solar cells with few-layer graphene were fabricated on silicon wafers by using the cyclododecane transfer method and outperformed reference cells made by standard methods.