Quantum Yield Research Articles

Boosting the Quantum Efficiency of Ionic Carbon Nitrides in Photocatalytic H2O2 Evolution via Controllable n → π* Electronic Transition Activation.

Hydrogen peroxide (H2O2) is a crucial chemical used in numerous industrial applications, yet its manufacturing relies on the energy-demanding anthraquinone process. Solar-driven synthesis of H2O2 is gaining traction as a promising research area, providing a sustainable method for its production. Herein, a controllable activation of n → π* electronic transition is presented to boost the photocatalytic H2O2 evolution in ionic carbon nitrides. This enhancement is achieved through the simultaneous introduction of structural distortions and defect sites (─C ≡ N groups and N vacancies) into the KPHI framework. The optimal catalyst (2%Ox-KPHI) reached an apparent quantum yield of 41% at 410nm without the need for any cocatalysts, outperforming most previously reported carbon nitride-based photocatalysts. Extensive experimental characterizations and theoretical calculations confirm that a corrugated configuration and the presence of defects significantly broaden the light absorption profile, improve carrier separation and migration, promote O2 adsorption, and lower the energy barriers for H2O2 desorption. Transient absorption spectroscopy indicates that the enhanced photocatalytic performance of 2%Ox-KPHI is largely attributed to the preferential migration of electrons at defect sites over extended timescales, following the diffusion of geminate carriers across the PHI sheets.

Mercaptopropionic acid-capped CdZnTe Quantum dots as Fluorescence Probe for Sensitive Detection of Cr(III) ions.

Although Cr(III) ions are essential for the human body, excessive amounts can lead to skin inflammation, allergic reactions, and genotoxicity. A highly sensitive fluorescence probe was developed using mercaptopropionic acid (MPA) capped CdZnTe quantum dots (QDs) synthesized via an aqueous solution heating method for precise detection of Cr(III) ions. The synthesized MPA-CdZnTe QDs had a size of 2.38 ± 0.13nm and exhibited a zinc-blende structure, with MPA molecules effectively capping the surface through Cd-S bonds. Investigation into the effects of reflux times and solution pH on the absorption and fluorescence spectra of MPA-CdZnTe QDs revealed the occurrence of Ostwald ripening during prolonged reflux processes. The quantum yield (QY) of the synthesized CdZnTe QDs could reach 89%, and the QY was higher under acidic conditions than alkaline. Leveraging the quenching effect of Cr(III) ions on MPA-CdZnTe QDs, a robust method for the quantitative detection of trace amounts of Cr(III) ions was established. Linear quenching behavior was observed within the concentration range of 3.33 × 10- 6 to 5.00 × 10- 4 mol L- 1 for Cr(III) ions, with the fluorescence quenching rate described by a linear regression equation: 1-F/F0 = 0.218 + 829.5268CCr(III). The limit of detection was determined to be 2.63 × 10- 6 mol L- 1. The mechanism of the fluorescence behavior of MPA capped CdZnTe QDs towards Cr(III) ions was photo-induced electron transfer.

Green Synthesis of Luminescent Carbon Dots from Ficus benghalensis Aerial Roots for Bioimaging.

In this work, carbon quantum dots (CQDs) were prepared using a one-step hydrothermal green synthesis method from a low-cost and eco-friendly renewable biomass, specifically the Ficus benghalensis aerial roots (FB-AR). For the past two decades, CQDs have been noted for their tunable emission spectrum, quantum yield, biocompatibility, photostability, and unique optoelectronic properties such as photoluminescence (PL), and fluorescence. The synthesized Ficus benghalensis carbon quantum dots (FB-CQDs) were characterized for their physical, structural, and chemical properties using XRD, Raman, HRTEM, XPS, FTIR, TG-DTG, UV-visible, and photoluminance analysis. XPS analysis confirmed the presence of phytoconstituent functionalities and the composition of components. The FB-CQDs, which exhibit long-range emissions, have potential applications in various biological and therapeutic fields. Their bioimaging capability is tested in Escherichia coli bacteria. However, despite their promising characteristics, the FB-CQDs showed no antibacterial inhibition against Escherichia coli and Staphylococcus aureus, likely due to its carbonization temperature.

Room‐Temperature Phosphorescence of Cocrystals of Aromatic Bisimides and Triplet Sensitizer Pt(acac)2

AbstractFour sterically shielded aromatic bisimides are synthesized and their ability to form cocrystals with the triplet sensitizer platinum(II) acetylacetonate (Pt(acac)2) is investigated. Single crystals of the individual electron‐deficient bisimides are studied first, two showing bright blue fluorescence with quantum yields of up to 28%, while the other two barely emit at all. After successful cocrystallization of all four aromatic bisimides with the electron‐rich Pt(II) complex, two different stoichiometries, either 1:1 or 1:2, are found in the crystalline solid state, whose absorbance and photoluminescence exhibit distinct bathochromic shifts. While two naphthalene bisimides show strong and long‐lived room‐temperature phosphorescence (RTP) with quantum yield exceeding 50%, the other two aromatic bisimides show only minor photoluminescence at RT, but a bright low‐temperature phosphorescence (LTP) at 80 K. Theoretical calculations reveal the importance of changing the magnetic quantum number ml of the involved d‐orbitals at the platinum center as well as the alignment of the Pt(II) center above an aromatic C─C bond for an efficient intersystem crossing in these hybrid systems.

Higly Luminescent Aceno[6]helicenones by Intramolecular Radical Cyclization.

Helicenes and helicenoid structures are promising candidates for future applications exploiting circularly polarized light. Ideal candidates should possess near-quantitative photoluminescence quantum yield, high a luminescence dissymmetry factor and an adjustable HOMO-LUMO gap. However, carbo[n]helicenes are poorly luminescent compounds and they absorb light mainly in the ultraviolet region. Here we show that the incorporation of a carbonyl group into helical scaffold significantly improves the fluorescence quantum yield and shifts the absorption to visible region. Although the carbonyl group is commonly considered as detrimental to efficient emission, fluorescence quantum yields up to Φ = 0.43 were recorded. A straightforward synthetic approach to a highly luminescent tetraceno[6]helicenone and an aza analogue has been developed. The key step is a radical cyclization which is achieving dehydrative π-extension. The aza-analogue was incorporated as an emitter in organic light emitting diodes (OLEDs) and showed good performance.

Au···I coinage bonds: Boosting photoluminescence efficiency and solid‐state molecular motion

AbstractCoinage bonds, a type of noncovalent interaction, occur between group 11 elements (Au, Ag, and Cu) with electron donor groups. Despite theoretical validation, empirical evidence remains limited. In this study, an aggregation‐induced emission (AIE)‐active Au(I) complex, ITCPAu, which exhibits Au···I coinage bonds, was revealed based on the single‐crystal X‐ray diffraction and theoretical calculations. Further examination of the luminescence properties of the ITCPAu revealed multiswitchable behavior, including mechanochromism and thermochromism. Nearly pure white‐light emission was achieved with Commission Internationale de L'Eclairage (CIE) 1931 chromaticity coordinates of (0.30, 0.31) by grinding the green‐emissive ITCPAu monomer crystals. Moreover, visualization and manipulation of solid‐state molecular motion (SSMM) in the yellow‐emissive ITCPAu dimer crystals, driven by the robust Au···I coinage bonds, were revealed through a combination of crystal engineering and luminescent properties. Furthermore, to support the robust Au···I coinage bonds, a versatile carrier for small solvent molecules in crystal lattices was developed for uptake and release. Our findings provide experimental and theoretical evidence for Au···I coinage bonds, highlighting their ability to boost photoluminescence quantum yield (PLQY) and trigger SSMM, emphasizing their potential in developing smart materials with stimuli‐responsive properties.

Antithermal-Quenching All-Inorganic Perovskite Crystals with Green Ultralong Persistent Luminescence for Advanced Anticounterfeiting Applications.

Long persistent luminescence (PersL) materials have revolutionized many fields of optoelectronics and photonics due to their applications in anticounterfeiting, information encryption, and in vivo bioimaging. Here, we reported a novel PersL crystal prepared by the heterovalent doping of Sb3+ into perovskite tetragonal phase RbCdCl3, comparing with the pristine non-perovskite orthorhombic phase analogue without PersL property. Surprisingly, under the UV light irradiation, the title crystals concurrently exhibit green ultralong PersL (>2400 s), high photoluminescence quantum yield (49.1%), and antithermal quenching in the range from 148 to 328 K. It was revealed by experimental results and theoretical analyses that green ultralong PersL and antithermal quenching of perovskite-phase RbCdCl3/Sb3+ crystals originate from the electron transition between the 5s2 level of the dopant Sb3+ and the electronic defect-induced trap states. Enlightened by the excellent optical properties, the tetragonal perovskite-phase RbCdCl3/Sb3+ PersL materials show promising application prospects in anticounterfeiting and encryption of information.

Simultaneous Structural and Electronic Engineering on Bi- and Rh-co-doped SrTiO3 for Promoting Photocatalytic Water Splitting.

Activating metal ion-doped oxides as visible-light-responsive photocatalysts requires intricate structural and electronic engineering, a task with inherent challenges. In this study, we employed a solid (template)-molten (dopants) reaction to synthesize Bi- and Rh-codoped SrTiO3 (SrTiO3 : Bi,Rh) particles. Our investigation reveals that SrTiO3 : Bi,Rh manifests as single-crystalline particles in a core (undoped)/shell (doped) structure. Furthermore, it exhibits a well-stabilized Rh3+ energy state for visible-light response without introducing undesirable trapping states. This precisely engineered structure and electronic configuration promoted the generation of high-concentration and long-lived free electrons, as well as facilitated their transfer to cocatalysts for H2 evolution. Impressively, SrTiO3 : Bi,Rh achieved an exceptional apparent quantum yield (AQY) of 18.9 % at 420 nm, setting a new benchmark among Rh-doped-based SrTiO3 materials. Furthermore, when integrated into an all-solid-state Z-Scheme system with Mo-doped BiVO4 and reduced graphene oxide, SrTiO3 : Bi,Rh enabled water splitting with an AQY of 7.1 % at 420 nm. This work underscores the significance of simultaneous structural and electronic engineering and introduces the solid-molten reaction as a viable approach for this purpose.

Fluorescence turn-off detection of myoglobin as a cardiac biomarker using water-stable L-glutamic acid functionalized cesium lead bromide perovskite quantum dots.

Water dispersible L-glutamic acid (Glu) functionalized cesium lead bromide perovskite quantum dots (CsPbBr3 PQDs), namely CsPbBr3@Glu PQDs were synthesized and used for the fluorescence "turn-off" detection of myoglobin (Myo). The as-prepared CsPbBr3@Glu PQDs exhibited an exceptional photoluminescence quantum yield of 25% and displayed emission peak at 520nm when excited at 380nm. Interestingly, thefluorescence "turn-off" analytical approach was designed to detect Myo using CsPbBr3@Glu PQDs as a simple optical probe. The developed probe exhibited awide linear range (0.1-25µM) and a detection limit of 42.42nM for Myo sensing. The CsPbBr3@Glu PQDs-based optical probe provides high ability to determineMyo in serum and plasma samples.

Simultaneous Structural and Electronic Engineering on Bi‐ and Rh‐co‐doped SrTiO3 for Promoting Photocatalytic Water Splitting

AbstractActivating metal ion‐doped oxides as visible‐light‐responsive photocatalysts requires intricate structural and electronic engineering, a task with inherent challenges. In this study, we employed a solid (template)‐molten (dopants) reaction to synthesize Bi‐ and Rh‐codoped SrTiO3 (SrTiO3 : Bi,Rh) particles. Our investigation reveals that SrTiO3 : Bi,Rh manifests as single‐crystalline particles in a core (undoped)/shell (doped) structure. Furthermore, it exhibits a well‐stabilized Rh3+ energy state for visible‐light response without introducing undesirable trapping states. This precisely engineered structure and electronic configuration promoted the generation of high‐concentration and long‐lived free electrons, as well as facilitated their transfer to cocatalysts for H2 evolution. Impressively, SrTiO3 : Bi,Rh achieved an exceptional apparent quantum yield (AQY) of 18.9 % at 420 nm, setting a new benchmark among Rh‐doped‐based SrTiO3 materials. Furthermore, when integrated into an all‐solid‐state Z‐Scheme system with Mo‐doped BiVO4 and reduced graphene oxide, SrTiO3 : Bi,Rh enabled water splitting with an AQY of 7.1 % at 420 nm. This work underscores the significance of simultaneous structural and electronic engineering and introduces the solid‐molten reaction as a viable approach for this purpose.

Elucidating the Supramolecular Interaction of Positively Supercharged Fluorescent Protein with Anionic Phthalocyanines.

Developing bioinspired materials to convert sunlight into electricity efficiently is paramount for sustainable energy production. Fluorescent proteins are promising candidates as photoactive materials due to their high fluorescence quantum yield and absorption extinction coefficients in aqueous media. However, developing artificial bioinspired photosynthetic systems requires a detailed understanding of molecular interactions and energy transfer mechanisms in the required operating conditions. Here, the supramolecular self-assembly and photophysical properties of fluorescent proteins complexed with organic dyes are investigated in aqueous media. Supercharged mGreenLantern protein, mutated to have a charge of +22, is complexed together with anionic zinc phthalocyanines having 4 or 16 carboxylate groups. The structural characterization reveals a strong electrostatic interaction between the moieties, accompanied by partial conformational distortion of the protein structure, yet without compromising the mGreenLantern chromophore integrity as suggested by the lack of emission features related to the neutral form of the chromophore. The self-assembled biohybrid shows a total quenching of protein fluorescence, in favor of an energy transfer process from the protein to the phthalocyanine, as demonstrated by fluorescence lifetime and ultrafast transient absorption measurements. These results provide insight into the rich photophysics of fluorescent protein-dye complexes, anticipating their applicability as water-based photoactive materials.

Multimode Luminescence Tailoring in PMA4Na(In,Sb)Cl8 Organic–inorganic Hybrid Metal Halide via Rigid Benzene Ring Induced Local Lattice Distortion

AbstractLow dimensional organic‐inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity‐forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow‐emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low‐dimensional OIMHs single crystal with a PLQY as high as 88 % was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity‐forbidden transition by strong spin‐orbit (SO) coupling and Jahn‐Teller (JT) interaction. The as‐prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1→1S0 transitions of Sb3+ in [SbCl6]3− octahedral caused by JT deformation. Moreover, wide‐range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3− octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti‐thermal quenching from 8 to 400 K owing to the suppression of non‐radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti‐counterfeiting and WLED applications.

Reactivity of a Morita-Baylis-Hillman Adduct Derivative Bearing a Triphenylamine Moiety with Lysine Models.

The reactivity of Morita-Baylis-Hillman Adduct (MBHA) derivative 7 was studied with different primary amine derivatives such as n-butylamine, Nα-acetyl-L-lysine methyl ester, and a poly-(L-lysine) derivative as lysine models to obtain information about the possible reactions in complex protein environments. MBHA derivative 7 reacted with n-butylamine or Nα-acetyl-L-lysine methyl ester producing monoadducts 9a or 9c, which showed bright emission features in the green region at 526-535 nm with photoluminescence quantum yield values in solutions of 73 % and 51 %, respectively. Based on these results, MBHA derivative 7 can be considered an interesting new fluorogenic probe potentially useful in the labelling of basic amino acid residues. Furthermore, similar to other MBHA derivatives, compound 7 showed the tendency to produce diadducts especially in polar solvents system where specific interactions between the extended aromatic moieties may play a major role.

Polydimethylsiloxanes - Based Fluorescent Probe for H2S Detection in Living Cells.

The development of fluorescent probes for H2S detection especially in living cells is of great significance due to its fundamental role as signal molecule. A promising scaffold for the development of such probes is polydimethylsiloxanes (PDMS), which is cost-effectiveness, non-toxicity, flexibility, and biocompatibility and easy to post-functionalize. Surprisingly, fluorescent probes for H2S detection based on PDMS have not been investigated. Moreover, 4-nitro - 2,1,3-benzoxadiazole (NBD) derivates provides high fluorescence quantum yield, a large molar absorption coefficient, and sensitivity to environmental changes. Through reasonable design and adjustment of substituents on the NBD group, precise control of its fluorescence properties can be achieved. Herein, a novel H2S fluorescent probe, P-NBD, was designed and synthesized by a one-step aromatic ring nucleophilic substitution of Cl-NBD with a PDMS derivative. Due to the occurrence of the cleavage reaction strategy and the intramolecular charge transfer process, P-NBD can detect H2S via a colorimetric method. The limit of detection is down to 93 nM. P-NBD demonstrated considerable detection capability comparable to other reported types of H2S probes. Moreover, the probe can also be utilized for H2S imaging in HeLa cells. This work provides new insights into the design and synthesis of novel H2S probes while also offering experimental evidence for the application of PDMS in cellular imaging.

Intense and Stable Blue Light Emission From CsPbBr3/Cs4PbBr6 Heterostructures Embedded in Transparent Nanoporous Films

AbstractLead halide perovskite nanocrystals are attractive for light emitting devices both as electroluminescent and color‐converting materials since they combine intense and narrow emissions with good charge injection and transport properties. However, while most perovskite nanocrystals shine at green and red wavelengths, the observation of intense and stable blue emission still remains a challenging target. In this work, a method is reported to attain intense and enduring blue emission (470–480 nm), with a photoluminescence quantum yield (PLQY) of 40%, originating from very small CsPbBr3 nanocrystals (diameter < 3 nm) formed by controllably exposing Cs4PbBr6 to humidity. This process is mediated by the void network of a mesoporous transparent scaffold in which the zero‐dimensional Cs4PbBr6 lattice is embedded, which allows the fine control over water adsorption and condensation that determines the optimization of the synthetic procedure and, eventually, the nanocrystal size. The approach provides a means to attain highly efficient transparent and stable blue light‐emitting films that complete the palette offered by perovskite nanocrystals for lighting and display applications.

TICT, and Deep-Blue Electroluminescence from Acceptor-Donor-Acceptor Molecules.

Donor-acceptor (D-A) materials based on butterfly-shaped molecules could inhibit exciton-migration-induced quenching due to molecular twist. To explore this attribute towards beneficial photophysical properties, three novel bipolar acceptor-donor-acceptor (A-D-A) molecules with triphenyl triazine end capping along with substitution ortho to the Tröger's base (TB) scaffold varying from H, Me, and F were explored. The installation of H/Me/F imparted an electron push-pull effect with concomitant maneuvering of photophysical properties. On increasing solvent polarity, a remarkable bathochromic shift with a significant decrease in emission efficiency was observed due to the twisted intramolecular charge transfer state (TICT). Emission enhancement in the ethylene glycol-water mixture and diminution in the THF-water mixture further confirmed the existence of TICT states in these TBs. The torsional dynamics in the excited state were also evidenced by the time-dependent density-functional theory (TD-DFT) calculations. Owing to the butterfly architecture of the TB that suppressed TICT, TB-Trzs exhibited a significant blue shift, accompanied by a favorable quantum yield in the solid state. Among the three compounds, Me-TB-Trz exhibited deep-blue photoluminescence and was explored as a dopant in organic light-emitting diodes (OLEDs) to obtain deep-blue electroluminescence of brightness 4128 cdm-2 and CIE coordinates of (0.16, 0.09).

Spacer Twisting Strategy to Realize Ultrabright Near-Infrared II Polymer Nanoparticles for Fluorescence Imaging-Guided Tumor Phototheranostics.

Conjugated polymers are becoming popular near-infrared II (NIR-II) phototheranostic agents (PTAs) due to their numerous advantages, such as high photostability, large molar extinction coefficients, and excellent photothermal properties. However, the strong π-π interactions between the chains of the conjugated polymers resulted in their generally low NIR-II emission quantum yields (QY). Therefore, the synthesis of conjugated polymers with high QY is an interesting but challenging task. Herein, we proposed a spacer twisting strategy to realize ultrabright NIR-II polymer nanoparticles for fluorescence imaging-guided tumor phototheranostics. Theoretical calculations indicated that the polymer PY-IT has the largest dihedral angle between the largely π-conjugated skeleton and the spacer, which can effectively inhibit intermolecular π-π stacking, resulting in an improved QY as high as 16.5% in nanoparticles. In addition, PY-IT NPs can effectively perform NIR-II imaging and photothermal treatment of tumors. The work presents some valuable guides for achieving ultrabright NIR-II polymeric PTAs with high QY.

High Quantum Yields and Energy Transfer Efficiency of Lanthanide‐Based Coordination Polymers as Luminescent Thermometer in Low Temperature Range

ABSTRACTLuminescent lanthanide‐based coordination polymers (LnCPs) present great potential in low‐temperature detection due to their convenience in contactless readout. High quantum yields and energy transfer efficiency are favored by LnCPs as luminescent thermometer. In this work, based on the thermogravimetric analysis and temperature‐dependent powder x‐ray diffraction, coordinated and isolated molecules of [Ln2(mip)3(H2O)8·4H2O]∞ (abbreviated as Ln2MIP) were removed by dehydration process. Combining luminescent measurement and calculation, both quantum yields and energy transfer efficiency between Tb3+ and Eu3+ have been greatly enhanced. Additionally, the Eu3+ intensity of dehydrated Gd0.2Tb1.08Eu0.72MIP displays excellent temperature sensing ability from 77 to 300 K with enhanced relative sensitivity. These results demonstrate the potential of LnCPs in low‐temperature sensing with high quantum yields and energy transfer efficiency.

Selective Recognition of the Dimeric NG16 Parallel G-Quadruplex Structure Using Synthetic Turn-On Red Fluorescent Protein Chromophore.

Red fluorescent protein (RFP)-based fluorescent probes that can selectively interact with specific nucleic acids are of great importance for therapeutic and bioimaging applications. Herein, we have reported the synthesis of RFP chromophores for selective recognition of G-quadruplex nucleic acids in vitro and ex vivo. We identified DFHBI-DM as a fluorescent turn-on probe that binds to the dimeric NG16 parallel quadruplex with superior selectivity and sensitivity over various parallel, antiparallel, and hybrid topologies. The binding of DFHBI-DM to NG16 exhibited excellent photophysical properties, including high binding affinity, large Stokes shift, high photostability, and quantum yield. The MD simulation study supports the 1:1 binding stoichiometry. It confirms the planar conformation of DFHBI-DM, which makes strong binding interactions with a flat quartet of NG16 compared to other antiparallel and hybrid topologies. The cell imaging and MTT assays revealed that DFHBI-DM is a biocompatible and efficient fluorescent probe for intracellular imaging of NG16. Overall, these results demonstrated that DFHBI-DM could be an effective fluorescent G4-stabilizing agent for the dimeric NG16 parallel quadruplex, and it could be a promising candidate for further exploration of bioimaging and therapeutic applications.

Triscyanocorrole, the Newest and Most Intriguing Member of the C1-Substituted Corrole Family.

Considering the potential advantages of minimally sized corroles for diverse applications, this study reports a facile access to cyano-substituted derivatives via a rare CF3/CN conversion. Investigation of the fully characterized gallium, phosphorus, and cobalt complexes discloses multiple effects of the meso-nitrile groups attached to the macrocycle. This corrole appears to be the most electron poor derivative which comes into play in the redox potentials of the corresponding complexes. Compared to its precursor, both the absorption and emission are strongly red shifted and the fluorescence lifetime and quantum yield are much larger. The coordination chemistry is affected as well, by virtue of axial ligands being perpendicular rather than parallel relative to each other.