Photoluminescence Quenching Research Articles

Deciphering the Atomic-Scale Structural Origin for Photoluminescence Quenching in Tin-Lead Alloyed Perovskite Nanocrystals.

The development of tin-lead alloyed halide perovskite nanocrystals (PNCs) is highly desirable for creating ultrastable, eco-friendly optoelectronic applications. However, the current incorporation of tin into the lead matrix results in severe photoluminescence (PL) quenching. To date, the precise atomic-scale structural origins of this quenching are still unknown, representing a significant barrier to fully realizing the potential of these materials. Here, we uncover the distinctive defect-related microstructures responsible for PL quenching using atomic-resolution scanning transmission electron microscopy and theoretical calculations. Our findings reveal an increase in point defects and Ruddlesden-Popper (RP) planar faults with increasing tin content. Notably, the point defects include a spectrum of vacancies and previously overlooked antisite defects with bromide vacancies and cation antisite defects emerging as the primary contributors to deep-level defects. Furthermore, the RP planar faults exhibit not only the typical rock-salt stacking pattern found in pure Pb-based PNCs but also previously undocumented microstructures rich in bromide vacancies and deep-level cation antisite defects. Direct strain imaging uncovers severe lattice distortion and significant inhomogeneous strain distributions caused by point defect aggregation, potentially breaking the local force balance and driving RP planar fault formation via lattice slippage. Our work illuminates the nature and evolution of defects in tin-lead alloyed halide perovskite nanocrystals and their profound impact on PL quenching, providing insights that support future material strategies in the development of less toxic tin-lead alloyed perovskite nanocrystals.

Elucidating the Mechanism of Copper-Induced Photoluminescence Quenching in 2-Phenylbenzimidazole-5-Sulfonic Acid.

To explore the possible impact of 2-Phenylbenzimidazole-5-sulfonic acid (PBSA) on the function of a sunscreen, in this work we investigate the binding of copper metal ions (Cu2+) to PBSA. Due to the existence of an intrinsic interaction phenomenon between Cu2+ ions and PBSA molecules, the photoluminescence (PL) quenching arises owing to the charge transfer from PBSA to Cu2+ ions. The mechanism of fluorescence quenching is probed experimentally following excitation at 306 nm by evaluating various quenching parameters with the help of the Stern-Volmer plot. Through the assessment of the values of the Stern-Volmer constant ( ) and bimolecular quenching rate constant ( ), it is deduced that the dynamic mode of PL quenching is operative between PBSA and Cu2+ ions. We evaluate the number of binding sites (n = 1) that advocate the presence of a single binding site in PBSA for Cu2+ ions. The numerical value of standard Gibbs free energy change, ~ -27.485 kJ.mol-1 implies the spontaneous binding between Cu2+ ions and PBSA molecules. The results obtained give an insight into the mechanism of metal-induced PL quenching of water soluble PBSA sunscreen.

Rücktitelbild: Photoluminescence Quenching of Hydrophobic Ag29 Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling (Angew. Chem. 12/2024)

Rücktitelbild: Photoluminescence Quenching of Hydrophobic Ag₂₉ Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling (Angew. Chem. 12/2024)

Back Cover: Photoluminescence Quenching of Hydrophobic Ag29 Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling (Angew. Chem. Int. Ed. 12/2024)

Back Cover: Photoluminescence Quenching of Hydrophobic Ag₂₉ Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling (Angew. Chem. Int. Ed. 12/2024)

Negative Thermal Quenching of Photoluminescence: An Evaluation from the Macroscopic Viewpoint.

Negative thermal quenching (NTQ) denotes that the integral emission spectral intensity of a given phosphor increases continuously with increasing temperature up to a certain elevated temperature. NTQ has been the subject of intensive investigations in recent years, and a large number of phosphors are reported to have exhibited NTQ. In this paper, a collection of results in the archival literature about NTQ of specific phosphors is discussed from a macroscopic viewpoint, focusing on the following three aspects: (1) Could the NTQ of a given phosphor be reproducible? (2) Could the associated data for a given phosphor exhibiting NTQ be in line with the law of the conservation of energy? (3) Could the NTQ of a given phosphor be demonstrated in a prototype WLED device? By analyzing typical cases based on common sense, we hope to increase awareness of the issues with papers reporting the NTQ of specific phosphors based on spectral intensity, along with the importance of maintaining stable and consistent measurement conditions in temperature-dependent spectral intensity measurement, which is a prerequisite for the validity of the measurement results.

Photoluminescence Quenching of Hydrophobic Ag29 Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling.

Exploiting emissive hydrophobic nanoclusters for hydrophilic applications remains a challenge because of photoluminescence (PL) quenching during phase transfer. In addition, the mechanism underlying PL quenching remains unclear. In this study, the PL-quenching mechanism was examined by analyzing the atomically precise structures and optical properties of a surface-engineered Ag29 nanocluster with an all-around-carboxyl-functionalized surface. Specifically, phase-transfer-triggered PL quenching was justified as molecular decoupling, which directed an unfixed cluster surface and weakened the radiative transition. Furthermore, emission recovery of the quenched nanoclusters was accomplished by using a supramolecular recoupling approach through the glutathione-addition-induced aggregation of cluster molecules, wherein the restriction of intracluster motion and intercluster rotation strengthened the radiative transition of the clusters. The results of this work offer a new perspective on structure-emission correlations for atomically precise nanoclusters and hopefully provide insight into the fabrication of highly emissive cluster-based nanomaterials for downstream hydrophilic applications.

Photoluminescence Quenching of Hydrophobic Ag29 Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling

AbstractExploiting emissive hydrophobic nanoclusters for hydrophilic applications remains a challenge because of photoluminescence (PL) quenching during phase transfer. In addition, the mechanism underlying PL quenching remains unclear. In this study, the PL‐quenching mechanism was examined by analyzing the atomically precise structures and optical properties of a surface‐engineered Ag29 nanocluster with an all‐around‐carboxyl‐functionalized surface. Specifically, phase‐transfer‐triggered PL quenching was justified as molecular decoupling, which directed an unfixed cluster surface and weakened the radiative transition. Furthermore, emission recovery of the quenched nanoclusters was accomplished by using a supramolecular recoupling approach through the glutathione‐addition‐induced aggregation of cluster molecules, wherein the restriction of intracluster motion and intercluster rotation strengthened the radiative transition of the clusters. The results of this work offer a new perspective on structure‐emission correlations for atomically precise nanoclusters and hopefully provide insight into the fabrication of highly emissive cluster‐based nanomaterials for downstream hydrophilic applications.

Frontispiece: Unusual Thermal Quenching of Photoluminescence from an Organic–Inorganic Hybrid [MnBr4]2−‐based Halide Mediated by Crystalline–Crystalline Phase Transition

Frontispiece: Unusual Thermal Quenching of Photoluminescence from an Organic–Inorganic Hybrid [MnBr₄]²⁻‐based Halide Mediated by Crystalline–Crystalline Phase Transition

Frontispiz: Unusual Thermal Quenching of Photoluminescence from an Organic–Inorganic Hybrid [MnBr4]2−‐based Halide Mediated by Crystalline–Crystalline Phase Transition

Frontispiz: Unusual Thermal Quenching of Photoluminescence from an Organic–Inorganic Hybrid [MnBr₄]²⁻‐based Halide Mediated by Crystalline–Crystalline Phase Transition

PLQ−sim: A computational tool for simulating photoluminescence quenching dynamics in organic donor/acceptor blends

Photoluminescence Quenching Simulator (PLQ−Sim) is a user−friendly software to study the photoexcited state dynamics at the interface between two organic semiconductors forming a blend: an electron donor (D), and an electron acceptor (A). Its main function is to provide substantial information on the photophysical processes relevant to organic photovoltaic and photothermal devices, such as charge transfer state formation and subsequent free charge generation or exciton recombination. From input parameters provided by the user, the program calculates the transfer rates of the D/A blend and employs a kinetic model that provides the photoluminescence quenching efficiency for initial excitation in the donor or acceptor. When calculating the rates, the user can choose to use disorder parameters to better describe the system. In addition, the program was developed to address energy transfer phenomena that are commonly present in organic blends. The time evolution of state populations is also calculated providing relevant information for the user. In this article, we present the theory behind the kinetic model, along with suggestions for methods to obtain the input parameters. A detailed demonstration of the program, its applicability, and an analysis of the outputs are also presented. PLQ−Sim is license free software that can be run via dedicated webserver nanocalc.org or downloading the program executables (for Unix, Windows, and macOS) from the PLQ-Sim repository on GitHub.

Unusual Thermal Quenching of Photoluminescence from an Organic–Inorganic Hybrid [MnBr4]2−‐based Halide Mediated by Crystalline–Crystalline Phase Transition

AbstractThe ability to generate and manipulate photoluminescence (PL) behavior has been of primary importance for applications in information security. Excavating novel optical effects to create more possibilities for information encoding has become a continuous challenge. Herein, we present an unprecedented PL temporary quenching that highly couples with thermodynamic phase transition in a hybrid crystal (DMML)2MnBr4 (DMML=N,N‐dimethylmorpholinium). Such unusual PL behavior originates from the anomalous variation of [MnBr4]2− tetrahedrons that leads to non‐radiation recombination near the phase transition temperature of 340 K. Remarkably, the suitable detectable temperature, narrow response window, high sensitivity, and good cyclability of this PL temporary quenching will endow encryption applications with high concealment, operational flexibility, durability, and commercial popularization. Profited from these attributes, a fire‐new optical encryption model is devised to demonstrate high confidential information security. This unprecedented optical effect would provide new insights and paradigms for the development of luminescent materials to enlighten future information encryption.

Unusual Thermal Quenching of Photoluminescence from an Organic-Inorganic Hybrid [MnBr4 ]2- -based Halide Mediated by Crystalline-Crystalline Phase Transition.

The ability to generate and manipulate photoluminescence (PL) behavior has been of primary importance for applications in information security. Excavating novel optical effects to create more possibilities for information encoding has become a continuous challenge. Herein, we present an unprecedented PL temporary quenching that highly couples with thermodynamic phase transition in a hybrid crystal (DMML)2 MnBr4 (DMML=N,N-dimethylmorpholinium). Such unusual PL behavior originates from the anomalous variation of [MnBr4 ]2- tetrahedrons that leads to non-radiation recombination near the phase transition temperature of 340 K. Remarkably, the suitable detectable temperature, narrow response window, high sensitivity, and good cyclability of this PL temporary quenching will endow encryption applications with high concealment, operational flexibility, durability, and commercial popularization. Profited from these attributes, a fire-new optical encryption model is devised to demonstrate high confidential information security. This unprecedented optical effect would provide new insights and paradigms for the development of luminescent materials to enlighten future information encryption.

Quenching of Photoluminescence of Carbon Dots by Metal Cations in Water: Estimation of Contributions of Different Mechanisms

Quenching of Photoluminescence of Carbon Dots by Metal Cations in Water: Estimation of Contributions of Different Mechanisms

Electric Field-Induced Quenching of MAPbI3 Photoluminescence in PeLED Architecture.

Photoluminescence (PL) measurements are a widely used technique for the investigation of perovskite-based materials and devices. Although electric field-induced PL quenching provides additional useful information, this phenomenon is quite complex and not yet clearly understood. Here, we address the PL quenching of methylammonium lead iodide (MAPbI3) perovskite in a light-emitting diode (PeLED) architecture. We distinguish two quenching mechanisms: (a) indirect quenching by slow irreversible or partially reversible material changes that occur gradually under the applied light and electric field and (b) direct quenching by the influence of the electric field on the charge carrier densities, their spatial distributions, and radiative recombination rates. Direct quenching, observed under the abrupt application of negative voltage, causes a decrease of the PL intensity. However, the PL intensity then partially recovers within tens of milliseconds as mobile ions screen the internal electric field. The screening time increases to hundreds of seconds at low temperatures, indicating activation energies for ion motion of about 80 meV. On the other hand, ultrafast time-resolved PL measurements revealed two main phases of direct quenching: an instantaneous reduction in the radiative carrier recombination rate, which we attribute to the electron and hole displacement within individual perovskite grains, followed by a second phase lasting hundreds of picoseconds, which is due to the charge carrier extraction and spatial separation of electron and hole "clouds" within the entire perovskite layer thickness.

Au13 Superatom Bearing Two Terpyridines at Coaxial Positions: Photoluminescence Quenching via Complexation with 3d Metal Ions

Abstract A gold cluster [Au13(dppe)5(EPTpy)2]3+ (dppe = 1,2-bis(diphenylphosphino)ethane, EPTpy-H = 4′-(4-ethynylphenyl)-2,2′:6′,2′′-terpyridine) was synthesized by ligand exchange reaction of [Au13(dppe)5Cl2]3+. Single-crystal X-ray diffraction analysis revealed that two terpyridyl moieties were σ-bonded to the coaxial positions of the icosahedral Au13 core. These two terpyridyl moieties were coordinated with 3d metal ions M2+ (M = Co, Ni, Cu, Zn) in acetonitrile solution under ambient conditions. The photoluminescence (PL) of [Au13(dppe)5(EPTpy)2]3+ with a quantum yield of 0.17 at ∼780 nm was almost completely quenched by coordination with Co2+, Ni2+, and Cu2+, while the PL was not affected by Zn2+ coordination. The metal-dependent PL quenching behavior is ascribed to the difference in the electronic structure of the metal ions. The energy transfer from the Au13 chromophore to the coordinated Co2+, Ni2+, or Cu2+ with an open electronic structure proceeds efficiently via an electron exchange mechanism, while the process is prohibited for Zn2+ with a closed electronic structure.

Rapid Detection of Ag(I) via Size-Induced Photoluminescence Quenching of Biocompatible Green-Emitting, l-Tryptophan-Scaffolded Copper Nanoclusters.

Atomically precise metal nanoclusters capped with small molecules like amino acids are highly favored due to their specific interactions and easy incorporation into biological systems. However, they are rarely explored due to the challenge of surface functionalization of nanoclusters with small molecules. Herein, we report the synthesis of a green-emitting (λex = 380 nm, λem = 500 nm), single-amino-acid (l-tryptophan)-scaffolded copper nanocluster (Trp-Cu NC) via a one-pot route under mild reaction conditions. The synthesized nanocluster can be used for the rapid detection of a heavy metal, silver (Ag(I)), in the nanomolar concentration range in real environmental and biological samples. The strong green photoluminescence intensity of the nanocluster quenched significantly upon the addition of Ag(I) due to the formation of bigger nanoparticles, thereby losing its energy quantization. A notable color change from light yellow to reddish-brown can also be observed in the presence of Ag(I), allowing its visual colorimetric detection. Portable paper strips fabricated with the Trp-Cu NC can be reliably used for on-site visual detection of Ag(I) in the micromolar concentration range. The Trp-Cu NC possesses excellent biocompatibility, making it a suitable nanoprobe for cell imaging; thus, it can act as an in vivo biomarker. The nanocluster showed a significant spectral overlap with anticancer drug doxorubicin and thus can be used as an effective fluorescence resonance energy transfer (FRET) pair. FRET results can reveal important information regarding the attachment of the drug to the nanocluster and hence its role as a potential drug carrier for targeted drug delivery within the human body.

Effect of partially reduced fullerenol‐graphene hybrid nanofiller on photophysical and super capacitance properties of fluorescence conducting polymer nanocomposites

AbstractThe effect of partially reduced fullerenol‐graphene oxide (rFGO) nanofiller on photophysical and super capacitance properties of binary nanocomposites containing phenylene‐alt‐thiophene fluorescence conducting polymer (FCP) were investigated. Nanocomposites were prepared by solution mixing, which allows uniform nanofiller distribution into the polymer matrix. Microscopic analyses of nanocomposites display homogeneous dispersion of nanofiller into the polymer matrix. Quenching of photoluminescence reveals the photosensitized electron transfer from light‐absorbing FCP (acting as an electron donor) to fullerenol‐graphene nanofiller (acting as an electron acceptor). The presence of partially reduced graphene sheets in rFGO nanofiller facilitates the photosensitized electron transfer along the surface and also through the interlayer channels of graphene sheets due to the pillar effect of fullerenol. UV–vis and photoluminescence spectroscopic characterization data reveal excellent interaction between filler and matrix, responsible for electron transfer mechanism. Super capacitance properties of binary nanocomposites in three different electrolytes (acid, neutral and alkaline) were also investigated and the best galvanic charge discharge result of 173 F/g at 2 A/g current density was obtained at 2 wt% loading up to 500th cycle for rFGO in acid electrolyte only. The material was ineffective in the alkaline electrolyte and showed poor results in neutral electrolyte. An attempt has been made to evaluate the structure–property relationship of nanocomposites from their thermal, photophysical, and electrochemical properties.

In situ synthesis of WS2 QDs for sensing of H2O2: Quenching and recovery of absorption and photoluminescence

In situ synthesis of WS2 QDs for sensing of H2O2: Quenching and recovery of absorption and photoluminescence

Abnormal Negative Thermal Quenching of Photoluminescence (PL) in Laser-Induced Exfoliated Black Phosphorus Quantum Dots for Applications as a Semiconductor PL Nanomaterial

Black phosphorus quantum dots (BPQDs) are promising candidates for semiconductor photoluminescence (PL) nanomaterials with the desired blue-violet emission and size-tuned optical response. Here, three prominent PL peaks were observed in the BPQDs with uniform nanosize, which were fabricated by pulsed-laser ablation of black phosphorus crystals. A sharp increase in the peak intensity was observed in the narrow temperature range of 225–250 K. This anomalous temperature dependence of the PL intensity is derived from negative thermal quenching, in which more electrons that are restricted in the intermediate states are thermally activated and excited to the lowest unoccupied molecular orbital (LUMO) with increasing temperature. The intermediate states were formed due to the defects induced by laser ablation. Consequently, the radiative transitions from LUMO to the σinner, σouter, and surface states dominate. By contrast, in the temperature ranges of 200–225 and 250–320 K, the PL intensity decreases because of normal thermal quenching, which usually occurs in conventional PL materials. The fitting result shows a nonmonotonicity similar to that in the negative thermal quenching semiconductors, reflecting the competition between normal and negative thermal quenching with changing temperature. Furthermore, the PL peak positions are blue-shifted with increasing temperature, which is associated with the stronger electron–phonon coupling and the lattice thermal expansion caused by transverse optical vibrations. The peak full width at half-maximum values broadened with temperature, which is attributed to the exciton–phonon interaction. This work is of great significance for not only a comprehensive understanding of the PL mechanism of the BPQDs but also the design of BPQDs-based optoelectrical nanodevices.

Fast electronic trapping and de-trapping by mid-gap states in CH3NH3PbCl3 single crystal

The assumed existence of mid-gap states and their roles acting as electronic traps in lead halide perovskites are under intensive discussion. Yet, knowledge about their physical characteristics remains limited due to the lack of directly accessed optical evidence. Here, we report direct access of spectroscopic responses by mid-gap states in one prototypical metal halide perovskite, CH3NH3PbCl3 single crystal. Mid-gap electronic trapping shown by sub-gap absorption and photoluminescence quenching is demonstrated. Quenching of the inter-band photoluminescence leads to instantaneous broadening in the energetic distributions of the mid-gap, making it hard to determine the energy of each individual mid-gap state. Therefore, the subsequent mid-gap luminescence following electronic de-trapping shows largely increased spectral linewidth and varied luminescence maxima energy. Time-resolved photoluminescence revealed the fast trapping and de-trapping kinetics by mid-gap states in the CH3NH3PbCl3 single crystal. By combining existing knowledge about mid-gap states in semiconductor crystals, we define a general on-lattice surface dangling bonds scenario serving as the creation of mid-gap states in the robust CH3NH3PbCl3 single crystal.