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A multi‐resonance (MR) fluorophore exhibiting circularly polarized luminescence (CPL) holds a significant promise for enhancing the utility of organic light‐emitting devices. To meet this demand, we have devised molecular dyads having azaoxaborin MR emitters based on homochiral (R)‐ and (S)‐1,1′‐bi‐2‐naphthol. The synthesized 12,12′‐di‐tert‐butyl‐9,9′‐bi(8,8′‐dioxa‐4b,4′b‐diaza‐14b,14′b‐diborafluorantheno[1,2,3‐de]tetracene) products (TBNBOCz) exhibit strong blue fluorescence, with a remarkable 100% fluorescence quantum yield and an extremely narrow full width at half‐maximum of 22 nm. However, unexpectedly, TBNBOCz exhibits negligible electric circular dichroism and CPL activities. Chiroptical investigations into the reaction precursors reveals an occurrence of racemization in the borylation step. This result emphasizes the importance of understanding synthetic processes and their impact on the chiroptical properties. [ABSTRACT FROM AUTHOR]

This research elucidates the effects of structural modulations on electroluminescent Au(I) complexes, shedding light on factors governing radiative and nonradiative processes. A series of Au(I) complexes, fortified with ortho‐substituents in carbene and amido ligands, are subjected to rigorous structural, photophysical, and quantum chemical investigations, which unveil distinct structural and electronic effects exerted by the ligands. The investigations reveal that nonradiative processes are governed primarily by the energy‐gap law. Radiative processes are observed to have a weak correlation with the mutual interactions of the molecular orbitals of carbene and amido ligands. Rather, it is discovered that an accumulation of the negative charge in the Au 5d orbital in the excited state decelerates radiative processes. The effectiveness of these findings is substantiated through the larger external quantum efficiency of electroluminescence devices employing the Au(I) complex, in comparison to those based on the archetypical Au(I) complex and the organic thermally activated delayed fluorescent molecule. These compelling revelations underscore the untapped potential of Au(I) complexes in the advancement of electroluminescence technology and advocate for continued investigations into the intriguing domain of ligand structural control. [ABSTRACT FROM AUTHOR]

Two‐coordinate coinage metal complexes have emerged as promising emitters for highly efficient organic light‐emitting devices (OLEDs). However, achieving efficient long‐wavelength electroluminescence emission from these complexes remains as a daunting challenge. To address this challenge, molecular design strategies aimed at bolstering the photoluminescence quantum yield (Φ) of Au(I) complex emitters in low‐energy emission regions are investigated. By varying amido ligands, a series of two‐coordinate Au(I) complexes is developed that exhibit photoluminescence peak wavelengths over a broad range of 533−750 nm. These complexes, in particular, maintain Φ values up to 10% even in the near‐infrared emission region, overcoming the constraints imposed by an energy gap. Quantum chemical calculations and photophysical analyses reveal the action of radiative control, which serves to overcome the energy gap law, becomes more pronounced as the overlap between hole and electron distributions (Sr(r)) in the excited state increases. It is further elucidated that Sr(r) increases with the distance between the hole‐distribution centroid and the nitrogen atom in an amido ligand. Finally, multilayer OLEDs involving the Au(I) complex emitters exhibit performances beyond the borderline of the electroluminescence wavelength−external quantum efficiency space set by previous devices of coinage metal complexes. [ABSTRACT FROM AUTHOR]

In this study, we introduced the electron‐donating group (−OH) to the aromatic rings of Ru(salophen)(NO)Cl (0) (salophenH2=N,N′‐(1,2‐phenylene)bis(salicylideneimine)) to investigate the influence of the substitution on NO photolysis and NO‐releasing dynamics. Three derivative complexes, Ru((o‐OH)2‐salophen)(NO)Cl (1), Ru((m‐OH)2‐salophen)(NO)Cl (2), and Ru((p‐OH)2‐salophen)(NO)Cl (3) were developed and their NO photolysis was monitored by using UV/Vis, EPR, NMR, and IR spectroscopies under white room light. Spectroscopic results indicated that the complexes were diamagnetic Ru(II)−NO+ species which were converted to low‐spin Ru(III) species (d5, S=1/2) and released NO radicals by photons. The conversion was also confirmed by determining the single‐crystal structure of the photoproduct of 1. The photochemical quantum yields (ΦNOs) of the photolysis were determined to be 0>1, 2, 3 at both the visible and UV excitations. Femtosecond (fs) time‐resolved mid‐IR spectroscopy was employed for studying NO‐releasing dynamics. The geminate rebinding (GR) rates of the photoreleased NO to the photolyzed complexes were estimated to be 0≃1, 2, 3. DFT and TDDFT computations found that the introduction of the hydroxyl groups elevated the ligand π‐bonding orbitals (π (salophen)), resulting in decrease of the HOMO‐LUMO gaps in 1–3. The theoretical calculations suggested that the Ru‐NNO bond dissociations of the complexes were mostly initiated by the ligand‐to‐ligand charge transfer (LLCT) of π(salophen)→π*(Ru−NO) with both the visible and UV excitations and the decreasing ΦNOs could be explained by the changes of the electronic structures in which the photoactivable bands of 1–3 have relatively less contribution of transitions related with Ru‐NO bond than those of 0. [ABSTRACT FROM AUTHOR]

In this paper, we propose an ultrahigh‐resolution organic light‐emitting diodes (OLEDs) pixels patterned by conventional photolithography through by incorporating silicone into phosphorescent small‐molecule networks. This silicone‐integrated phosphorescent organic light‐emitting diode (SI‐phOLED), in which silicone molecules are homogeneously crosslinked with small‐molecule light‐emitting materials, can effortlessly achieve to 3,000 PPI ultrahigh‐resolution patterns using the photolithography process. [ABSTRACT FROM AUTHOR]

Circularly polarized luminescence (CPL) with tunable chirality is currently a challenging issue in the development of supramolecular nanomaterials. We herein report the formation of helical nanoribbons which grow into helical tubes through dynamic helicity inversion. For this, chiral PtII complexes of terpyridine derivatives, namely S‐trans‐1 and R‐trans‐1, with respective S‐ and R‐alanine subunits and incorporating trans‐double bonds in the alkyl chain were prepared. In DMSO/H2O (5 : 1 v/v), S‐trans‐1 initially forms a fibrous self‐assembled product, which then undergoes dynamic transformation into helical tubes (left‐handed or M‐type) through helical ribbons (right‐handed or P‐type). Interestingly, both helical supramolecular architectures are capable of emitting CPL signals. The metastable helical ribbons show CPL signals (glum=±4.7×10−2) at 570 nm. Meanwhile, the nanotubes, which are the thermodynamic products, show intense CPL signals (glum=±5.6×10−2) at 610 nm accompanied by helicity inversion. This study provides an efficient way to develop highly dissymmetric CPL nanomaterials by regulating the morphology of metallosupramolecular architectures. [ABSTRACT FROM AUTHOR]

NO photorelease and its dynamics for two {RuNO}6 complexes, Ru(salophen)(NO)Cl (1) and Ru(naphophen)(NO)Cl (2), with salen-type ligands bearing π-extended systems (salophenH2 = N,N′-(1,2-phenylene)-bis(salicylideneimine) and naphophenH2 = N,N′-1,2-phenylene-bis(2-hydroxy-1-naphthylmethyleneimine)) were investigated. NO photolysis was performed under white room light and monitored by UV/Vis, EPR, and NMR spectroscopies. NO photolysis was also performed under 459 and 489 nm irradiation for 1 and 2, respectively. The photochemical quantum yields of the NO photolysis (ΦNO) of both 1 and 2 were determined to be 9% at the irradiation wavelengths. The structural and spectroscopic characteristics of the complexes before and after the photolysis confirmed the conversion of diamagnetic Ru(II)(L)(Cl)–NO+ to paramagnetic S = ½ Ru(III)(L)(Cl)–solvent by photons (L = salophen2− and naphophen2−). The photoreleased NO radicals were detected by spin-trapping EPR. DFT and TDDFT calculations found that the photoactive bands are configured as mostly the ligand-to-ligand charge transfer (LLCT) of π(L) → π*(Ru–NO), suggesting that the NO photorelease was initiated by the LLCT. Dynamics of NO photorelease from the complexes in DMSO under 320 nm excitation were investigated by femtosecond (fs) time-resolved mid-IR spectroscopy. The primary photorelease of NO occurred for less than 0.32 ps after the excitation. The rate constants (k−1) of the geminate rebinding of NO to the photolyzed 1 and 2 were determined to be (15 ps)−1 and (13 ps)−1, respectively. The photochemical quantum yields of NO photolysis (ΦNO, λ = 320 nm) were estimated to be no higher than 14% for 1 and 11% for 2, based on the analysis of the fs time-resolved IR data. The results of fs time-resolved IR spectroscopy and theoretical calculations provided some insight into the overall kinetic reaction pathway, localized electron pathway or resonance pathway, of the NO photolysis of 1 and 2. Overall, our study found that the investigated {RuNO}6 complexes, 1 and 2, with planar N2O2 ligands bearing π-extended rings effectively released NO under visible light. [ABSTRACT FROM AUTHOR]

Integration of distinct materials to form heterostructures enables the proposal of new functional devices based on emergent physical phenomena beyond the properties of the constituent materials. The optical responses and electrical transport characteristics of heterostructures depend on the charge and exciton transfer (CT and ET) at the interfaces, determined by the interfacial energy level alignment. In this work, heterostructures consisting of aggregates of fluorescent molecules (DY1) and 2D semiconductor MoS2 monolayers are fabricated. Photoluminescence spectra of DY1/MoS2 show quenching of the DY1 emission and enhancement of the MoS2 emission, indicating a strong electronic interaction between these two materials. Nanoscopic mappings of the light‐induced contact potential difference changes rule out the CT process at the interface. Using femtosecond transient absorption spectroscopy, the rapid interfacial ET process from DY1 aggregates to MoS2 and a fourfold extension of the exciton lifetime in MoS2 are elucidated. These results suggest that the integration of 2D inorganic semiconductors with fluorescent molecules can provide versatile approaches to engineer the physical characteristics of materials for both fundamental studies and novel optoelectronic device applications. [ABSTRACT FROM AUTHOR]