scholarly journals Ultrabright Au@Cu14 nanoclusters: 71.3% phosphorescence quantum yield in non-degassed solution at room temperature

2021 ◽  
Vol 7 (2) ◽  
pp. eabd2091
Author(s):  
Yongbo Song ◽  
Yingwei Li ◽  
Meng Zhou ◽  
Xuan Liu ◽  
Hao Li ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Biomedical Applications ◽  
Room Temperature ◽  
Organometallic Complexes ◽  
Metal Nanoclusters ◽  
Electron Dynamics ◽  
Electronic Engineering ◽  
Phosphorescence Quantum Yield ◽  
Phosphorescence Emission ◽  
Very High

The photoluminescence of metal nanoclusters is typically low, and phosphorescence emission is rare due to ultrafast free-electron dynamics and quenching by phonons. Here, we report an electronic engineering approach to achieving very high phosphorescence (quantum yield 71.3%) from a [Au@Cu14(SPhtBu)12(PPh(C2H4CN)2)6]+ nanocluster (abbreviated Au@Cu14) in non-degassed solution at room temperature. The structure of Au@Cu14 has a single-Au-atom kernel, which is encapsulated by a rigid Cu(I) complex cage. This core-shell structure leads to highly efficient singlet-to-triplet intersystem crossing and suppression of nonradiative energy loss. Unlike the phosphorescent organic materials and organometallic complexes—which require de-aerated conditions due to severe quenching by air (i.e., O2)—the phosphorescence from Au@Cu14 is much less sensitive to air, which is important for lighting and biomedical applications.

A homoleptic, all-alkynyl-stabilized highly luminescent Au8Ag8cluster with a single crystal X-ray structure

2016 ◽  
Vol 45 (32) ◽  
pp. 12772-12778 ◽  
Author(s):  
Rui Zhang ◽  
Chongyang Zhao ◽  
Xiumin Li ◽  
Zongyao Zhang ◽  
Xicheng Ai ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Single Crystal ◽  
Room Temperature ◽  
X Ray ◽  
Ag Cluster ◽  
Very High

An all-alkynyl-stabilized, intensely luminescent Au–Ag cluster was synthesized and characterized with a very high solution quantum yield at room temperature.

Room-Temperature Luminescence Properties of p-Aminobenzoic Acid and 4-Phenylphenol Adsorbed on α-Cyclodextrin/NaCl Mixtures

1988 ◽  
Vol 42 (4) ◽  
pp. 619-624 ◽  
Author(s):  
J. M. Bello ◽  
R. J. Hurtubise
Keyword(s):  
Quantum Yield ◽  
Solid Surface ◽  
Rate Constants ◽  
Room Temperature ◽  
Aminobenzoic Acid ◽  
Phosphorescence Lifetime ◽  
Phosphorescence Quantum Yield ◽  
Sample Preparation Procedure ◽  
Nonradiative Transitions ◽  
Yield Values

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on α-cyclodextrin/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol on α-cyclodextrin/NaCl mixtures. In addition, the percentages of radiative and nonradiative transitions were calculated for the two compounds. The various luminescence parameters obtained in this work provided important insights into the analyte/α-cyclodextrin substrate interactions responsible for the observed solid-surface room-temperature fluorescence (RTF) and phosphorescence (RTP). Furthermore, the RTF and RTP intensities of PABA and 4-phenylphenol were obtained from several α-cyclodextrin/NaCl mixtures. These data showed the importance of the initial wet chemistry in the sample preparation procedure.

scholarly journals A High Value, Linear and Tunable CMOS Pseudo-Resistor for Biomedical Applications

2019 ◽  
Vol 28 (06) ◽  
pp. 1950096 ◽  
Author(s):  
R. Nagulapalli ◽  
K. Hayatleh ◽  
S. Barker ◽  
P. Georgiou ◽  
F. J. Lidgey
Keyword(s):  
Biomedical Applications ◽  
Room Temperature ◽  
Cutoff Frequency ◽  
Na Current ◽  
Current Generator ◽  
Temperature Drift ◽  
Low Pass ◽  
Low Distortion ◽  
High Pass ◽  
Very High

A subthreshold MOS-based pseudo-resistor featuring a very high value and ultra-low distortion is proposed. A bandpass neural amplifier with a very low high-pass cutoff frequency is designed, to demonstrate the linearity of the proposed resistor. A BJT less CTAT current generator has been introduced to minimize the temperature drift of the resistor and make tuning easier. The standalone resistor has achieved 0.5% better linearity and a 12% improved temperature coefficient over the existing architectures. A neural amplifier has been designed with the proposed resistor as a feedback element. It demonstrated 31[Formula: see text]dB mid-band gain and a low-pass cutoff frequency of 0.85[Formula: see text]Hz. The circuit operates from a 1[Formula: see text]V supply and draws 950[Formula: see text]nA current at room temperature.

scholarly journals Thermochemically Stable Liquid-Crystalline Gold(I) Complexes Showing Enhanced Room Temperature Phosphorescence

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 227 ◽  
Author(s):  
Yuki Kuroda ◽  
Shin-ya Nakamura ◽  
Katam Srinivas ◽  
Arruri Sathyanarayana ◽  
Ganesan Prabusankar ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Rational Design ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Decomposition Temperature ◽  
Ambient Conditions ◽  
Room Temperature Phosphorescence ◽  
Light Emitting ◽  
Phosphorescence Quantum Yield ◽  
Thermochemical Stability

Gold(I) complexes are some of the most attractive materials for generating aggregation-induced emission (AIE), enabling the realization of novel light-emitting applications such as chemo-sensors, bio-sensors, cell imaging, and organic light-emitting diodes (OLEDs). In this study, we propose a rational design of luminescent gold complexes to achieve both high thermochemical stability and intense room temperature phosphorescence, which are desirable features in practical luminescent applications. Here, a series of gold(I) complexes with ligands of N-heterocyclic carbene (NHC) derivatives and/or acetylide were synthesized. Detailed characterization revealed that the incorporation of NHC ligands could increase the molecular thermochemical stability, as the decomposition temperature was increased to ~300 °C. We demonstrate that incorporation of both NHC and acetylide ligands enables us to generate gold(I) complexes exhibiting both high thermochemical stability and high room-temperature phosphorescence quantum yield (>40%) under ambient conditions. Furthermore, we modified the length of alkoxy chains at ligands, and succeeded in synthesizing a liquid crystalline gold(I) complex while maintaining the relatively high thermochemical stability and quantum yield.

Changes in the Photophysical Properties with Heavy Atoms and the Effects of Modulus for 4-Phenylphenol in Solid-Matrix Luminescence

1992 ◽  
Vol 46 (6) ◽  
pp. 988-993 ◽  
Author(s):  
Barbara B. Purdy ◽  
Robert J. Hurtubise
Keyword(s):  
Quantum Yield ◽  
Low Temperature ◽  
Young’S Modulus ◽  
Filter Paper ◽  
Room Temperature ◽  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Phosphorescence Quantum Yield ◽  
Atom Effect ◽  
Fluorescence And Phosphorescence

Fluorescence and phosphorescence quantum yields and fluorescence and phosphorescence lifetimes were obtained for 4-phenylphenol adsorbed on filter paper with either NaCl, NaBr, or Nal at 296 and 93 K. From these data several photophysical parameters were calculated and compared. In general, the photophysical data showed that the heavy-atom effect was operative, with NaI showing the greatest effect. However, NaBr at 93 K showed both the heavy-atom effect and another effect which was particular to NaBr. For 4-phenylphenol with NaI, very little increase occurred for the phosphorescence quantum yield from 296 to 93 K, which indicated that almost maximum phosphorescence quantum yield was achieved at room temperature for 4-phenylphenol with NaI present. The increase in phosphorescence lifetime for 4-phenylphenol from room temperature to low temperature was shown to be related to the increase in the Young's modulus of filter paper as the temperature was lowered. Calculated phosphorescence lifetimes at room temperature and at low temperature with equations that included Young's modulus values agreed very well with experimental lifetime values.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

scholarly journals Synthesis and Physicochemical Properties of [(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-thiophen-5-yl-substituted Tetrapyrazinoporphyrazine with Magnesium(II) Ion

2021 ◽  
Vol 11 (6) ◽  
pp. 2576
Author(s):  
Sebastian Lijewski ◽  
Jiří Tydlitát ◽  
Beata Czarczynska-Goslinska ◽  
Milan Klikar ◽  
Jadwiga Mielcarek ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
2D Nmr ◽  
Nmr Studies ◽  
Oxygen Formation ◽  
Nmr Techniques ◽  
Flash Column Chromatography ◽  
Photochemical Stability ◽  
Singlet Oxygen Formation ◽  
Very High

Tetrapyrazinoporphyrazine with peripheral menthol-thiophenyl substituents was synthesized using Linstead conditions and purified by flash column chromatography. The optimized synthetic and purification procedures allowed us to obtain a new macrocycle with 36% yield. Tetrapyrazinoporphyrazine derivative was characterized by UV–Vis and NMR spectroscopy, as well as MS spectrometry. Complex NMR studies using 1D and 2D NMR techniques allowed the analysis of the bulky menthol-thiophenyl substituted periphery of the new macrocycle. Further, photochemical stability and singlet oxygen quantum yield were determined by indirect method with diphenylisobenzofuran. The new tetrapyrazinoporphyrazine revealed low generation of singlet oxygen with a quantum yield of singlet oxygen formation at 2.3% in dimethylformamide. In turn, the macrocycle under irradiation with visible light presented very high stability with quantum yield for photostability of 9.59 × 10−6 in dimethylformamide, which figures significantly exceed the border for its classification as a stable porphyrinoid (10−4–10−5).

Protein-protected metal nanoclusters as diagnostic and therapeutic platforms for biomedical applications

2021 ◽  
Author(s):  
Iman Zare ◽  
Daniel M. Chevrier ◽  
Anna Cifuentes-Rius ◽  
Nasrin Moradi ◽  
Yunlei Xianyu ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Metal Nanoclusters

Pure room temperature phosphorescence emission of organic host-guest doped system with quantum efficiency of 64%

2021 ◽  
Author(s):  
Xiaoqing Liu ◽  
Wenbo Dai ◽  
Qian Junjie ◽  
Yunxiang Lei ◽  
Miaochang Liu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Room Temperature ◽  
Room Temperature Phosphorescence ◽  
Halogen Atoms ◽  
System P ◽  
Phosphorescence Emission

A new doped system with pure phosphorescent emission is constructed using four 1-(4-(diphenylamino)phenyl)-2-phenylethan-1-one derivatives containing halogen atoms as the guests and benzophenone as the host. That is, the doped system...

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