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"Xie, Feng-Ming"
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Nondestructive halide exchange via SN2-like mechanism for efficient blue perovskite light-emitting diodes
2024
Blue perovskite light-emitting diodes (PeLEDs) still remain poorly developed due to the big challenge of achieving high-quality mixed-halide perovskites with wide optical bandgaps. Halide exchange is an effective scheme to tune the emission color of PeLEDs, while making perovskites susceptible to high defect density due to solvent erosion. Herein, we propose a versatile strategy for nondestructive in-situ halide exchange to obtain high-quality blue perovskites with low trap density and tunable bandgaps through long alkyl chain chloride incorporated chloroform post-treatment. In comparison with conventional halide exchange method, the ionic exchange mechanism of the present strategy is similar to a bimolecular nucleophilic substitution process, which simultaneously modulates perovskite bandgaps and inhibits new halogen vacancy generation. Consequently, efficient PeLEDs across blue spectral regions are obtained, exhibiting external quantum efficiencies of 23.6% (sky-blue emission at 488 nm), 20.9% (pure-blue emission at 478 nm), and 15.0% (deep-blue emission at 468 nm), respectively.
Zhang et al. report non-destructive halide exchange by employing butylammonium halide incorporated post-treatment to achieve perovskite with low trap density and tuneable bandgap for blue LEDs, with external quantum efficiencies of 23.6%, 20.9%, and 15.5% for emission peaks at 488, 478, and 468 nm, respectively.
Journal Article
Harnessing plasmon-exciton energy exchange for flexible organic solar cells with efficiency of 19.5
2025
The plasmonic effects have unlocked remarkable advancements in modern optoelectronics, enabling enhanced light-matter interactions for applications ranging from sensing to photovoltaics. However, the nonradiative damping of plasmonic effects causes parasitic absorption which limits the light-utilization efficiency of optoelectronics, particularly for photovoltaic cells. Herein, we propose a plasmon energy recycling scheme consisting of green fluorophore (BCzBN) and nickel oxide to compensate for the plasmon energy loss. The plasmons trapped in silver nanowire (AgNW) electrodes are coupled to green emission through plasmon-exciton energy exchange. Backward electron and energy transfer are inhibited due to the spectral mismatch and energy level offset. The optically enhanced flexible AgNW electrode exhibits an improvement of 10.74% in transmittance, yielding flexible organic solar cells with an efficiency of 19.51% and a certified value of 18.69%. This innovative strategy provides a pathway for overcoming plasmon energy losses in plasmonic optoelectronics, opening horizons for highly efficient flexible photovoltaics and plasmonic devices.
The parasitic absorption caused by nonradiative damping of plasmonic effects limits the light utilization efficiency of optoelectronics. Here, authors employ green fluorophore and nickel oxide to recycle plasmon energy, achieving maximum device efficiency of 19.51% for flexible organic solar cells.
Journal Article
High‐Performance Nondoped Blue Delayed Fluorescence Organic Light‐Emitting Diodes Featuring Low Driving Voltage and High Brightness
2020
Thermally activated delayed fluorescence (TADF) provides great potential for the realization of efficient and stable organic light‐emitting diodes (OLEDs). However, it is still challenging for blue TADF emitters to simultaneously achieve high efficiency, high brightness, and low Commission Internationale de l'Eclairage (CIE) y coordinate (CIEy) value. Here, the design and synthesis of two new benzonitrile‐based TADF emitters (namely 2,6‐di(9H‐carbazol‐9‐yl)‐3,5‐bis(3,6‐diphenyl‐9H‐carbazol‐9‐yl)benzonitrile (2PhCz2CzBn) and 2,6‐di(9H‐carbazol‐9‐yl)‐3,5‐bis(3,6‐di‐tert‐butyl‐9H‐carbazol‐9‐yl)benzonitrile (2tCz2CzBn)) with a symmetrical and rigid heterodonor configuration are reported. The TADF OLEDs doped with both the emitters can achieve a high external quantum efficiency (EQE) over 20% and narrowband blue emission of 464 nm with a CIEy < 0.2. Moreover, the incorporation of a terminal tert‐butyl group can weaken the intermolecular π–π stacking in the nondoped TADF emitter, and thus significantly suppress self‐aggregation‐caused emission quenching for enhanced delayed fluorescence. A peak EQE of 21.6% is realized in the 2tCz2CzBn‐based nondoped device with an extremely low turn‐on voltage of 2.7 V, high color stability, a high brightness over 20 000 cd m−2, a narrow full‐width at half‐maximum of 70 nm, and CIE color coordinates of (0.167, 0.248). A new blue thermally activated delayed fluorescence emitter of 2tCz2CzBn is synthesized with a symmetrical and rigid heterodonor configuration, enabling significant suppression of self‐aggregation‐caused emission quenching. High‐performance nondoped organic light‐emitting diodes are achieved with a high external quantum efficiency of 21.6%, an extremely low turn‐on voltage of 2.7 V, and narrowband blue emission.
Journal Article
Interfacial “Anchoring Effect” Enables Efficient Large‐Area Sky‐Blue Perovskite Light‐Emitting Diodes
by
Gao, Xingyu
,
Cai, Xiao‐Yi
,
Xie, Feng‐Ming
in
anchoring effect
,
Contact angle
,
Crystallization
2021
While tremendous progress has recently been made in perovskite light‐emitting diodes (PeLEDs), large‐area blue devices feature inferior performance due to uneven morphologies and vast defects in the solution‐processed perovskite films. To alleviate these issues, a facile and reliable interface engineering scheme is reported for manipulating the crystallization of perovskite films enabled by a multifunctional molecule 2‐amino‐1,3‐propanediol (APDO)‐triggered “anchoring effect” at the grain‐growth interface. Sky‐blue perovskite films with large‐area uniformity and low trap states are obtained, showing the distinctly improved radiative recombination and hole‐transport capability. Based on the APDO‐induced interface engineering, synergistical boost in device performance is achieved for large‐area sky‐blue PeLED (measuring at 100 mm2) with a peak external quantum efficiency (EQE) of 9.2% and a highly prolonged operational lifetime. A decent EQE up to 6.1% is demonstrated for the largest sky‐blue device emitting at 400 mm2. A facile and effective grain‐growth manipulation scheme enabled by interface “anchoring effect” is proposed for high‐quality sky‐blue perovskite emitter. Remarkable boost in device performance is achieved for large‐scale sky‐blue perovskite LEDs with peak external quantum efficiencies of 9.2% and 6.1% measured at scales of 100 and 400 mm2, respectively.
Journal Article
Hot‐electron emission‐driven energy recycling in transparent plasmonic electrode for organic solar cells
2022
Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics. However, the nonradiative damping of surface plasmon polaritons (SPPs) during coupling with sunlight results in the conversion of the excited hot‐electrons to heat, which limits the absorption of light and generation of photocurrent. Herein, an energy recycling strategy driven by hot‐electron emission for recycling the SPP energy trapped in the plasmonic electrodes is proposed. A transparent silver‐based plasmonic metal electrode (A‐PME) with a periodic hexagonal nanopore array is constructed, which is combined with a luminescent organic emitter for radiative recombination of the injected hot‐electrons. Owing to the suppressed SPP energy loss via broadband hot‐electron emission, the A‐PME achieves an optimized optical transmission with an average transmittance of over 80% from 380 to 1200 nm. Moreover, the indium‐tin‐oxide‐free organic solar cells yield an enhanced light harvesting with a power conversion efficiency of 16.1%. Hot‐electron emission approach is proposed to recycle the energy of surface plasmon polaritons (SPPs) in photovoltaics by combining the transparent silver‐based plasmonic metal electrode (A‐PME) with a luminescent organic emitter. The nonradiative SPP damping in A‐PMEs is drastically restrained, achieving efficient organic solar cells with a power conversion efficiency of over 16%.
Journal Article
Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives
2018
Two novel D–A bipolar blue phosphorescent host materials based on phenothiazine-5,5-dioxide: 3-(9 H -carbazol-9-yl)-10-ethyl-10 H -phenothiazine-5,5-dioxide (CEPDO) and 10-butyl-3-(9 H -carbazol-9-yl)-10 H -phenothiazine-5,5-dioxide (CBPDO) were synthesized and characterized. The photophysical, electrochemical and thermal properties were systematically investigated. CEPDO and CBPDO not only have a high triplet energy but also show a bipolar behavior. Moreover, their fluorescence emission peaks are in the blue fluorescence region at 408 nm and the fluorescence quantum efficiency (Φ) of CEPDO and CBPDO were 62.5% and 59.7%, respectively. Both CEPDO and CBPDO showed very high thermal stability with decomposition temperatures ( T d ) of 409 and 396 °C as well as suitable HOMO and LUMO energy levels. This preferable performance suggests that CEPDO and CBPDO are alternative bipolar host materials for the PhOLEDs.
Journal Article
Nondestructive halide exchange via S N 2-like mechanism for efficient blue perovskite light-emitting diodes
2024
Blue perovskite light-emitting diodes (PeLEDs) still remain poorly developed due to the big challenge of achieving high-quality mixed-halide perovskites with wide optical bandgaps. Halide exchange is an effective scheme to tune the emission color of PeLEDs, while making perovskites susceptible to high defect density due to solvent erosion. Herein, we propose a versatile strategy for nondestructive in-situ halide exchange to obtain high-quality blue perovskites with low trap density and tunable bandgaps through long alkyl chain chloride incorporated chloroform post-treatment. In comparison with conventional halide exchange method, the ionic exchange mechanism of the present strategy is similar to a bimolecular nucleophilic substitution process, which simultaneously modulates perovskite bandgaps and inhibits new halogen vacancy generation. Consequently, efficient PeLEDs across blue spectral regions are obtained, exhibiting external quantum efficiencies of 23.6% (sky-blue emission at 488 nm), 20.9% (pure-blue emission at 478 nm), and 15.0% (deep-blue emission at 468 nm), respectively.
Journal Article
A novel method for evaluating brain function and microstructural changes in Parkinson's disease
by
Ming-fang Jiang Feng Shi Guang-ming Niu Sheng-hui Xie Sheng-yuan Yu
in
Cardiovascular disease
,
Dopamine
,
Hospitals
2015
In this study,microstructural brain damage in Parkinson's disease patients was examined using diffusion tensor imaging and tract-based spatial statistics.The analyses revealed the presence of neuronal damage in the substantia nigra and putamen in the Parkinson's disease patients.Moreover,disease symptoms worsened with increasing damage to the substantia nigra,confirming that the substantia nigra and basal ganglia are the main structures affected in Parkinson's disease.We also found that microstructural damage to the putamen,caudate nucleus and frontal lobe positively correlated with depression.Based on the tract-based spatial statistics,various white matter tracts appeared to have microstructural damage,and this correlated with cognitive disorder and depression.Taken together,our results suggest that diffusion tensor imaging and tract-based spatial statistics can be used to effectively study brain function and microstructural changes in patients with Parkinson's disease.Our novel findings should contribute to our understanding of the histopathological basis of cognitive dysfunction and depression in Parkinson's disease.
Journal Article
Role of rat liver cytochrome P450 3A and 2D in metabolism of imrecoxib
by
Hai-yan XU Zhi-yong XIE Peng ZHANG Jin SUN Feng-ming cno Zong-ru GUO Da-fang ZHONG
in
Animals
,
Biotransformation
,
Cyclooxygenase 2 Inhibitors - metabolism
2006
Aim: To investigate the in vitro metabolism of imrecoxib in rat liver microsomes and to identify the cytochrome P450 (CYP) forms involved in its metabolism. Methods: Liver microsomes of Wistar rats were prepared using an ultracentrifuge, The in vitro metabolism of imrecoxib was studied by incubation with rat liver microsomes. To characterize the CYP forms involved in the 4'-methyl hydroxylation of imrecoxib, the effects of typical CYP inducers (such as dexamethasone, isoniazid and β-naphthoflavone) and of CYP inhibitors (such as ketoconazole, quinine, α-naphthoflavone, methylpyrazole, and cimetidine) on the formation rate of 4'-hydroxymethyl imrecoxib were investigated. Results: Imrecoxib was metabolized to 3 metabolites by rat liver microsomes: 4'-hydroxymethyl imrecoxib (M4), 4'-hydroxymethyl-5-hydoxyl imrecoxib (M3), and 4'-hydroxymethyl-5-carbonyl imrecoxib (M5). Over the imrecoxib concentration range studied (5-600 μmol/L), the rate of 4'-methyl hydroxylation conformed to monophasic MichaelisMenten kinetics. Dexamethasone significantly induced the formation of M4. Ketoconazole markedly lowered the metabolic rate of imrecoxib in a concentration-dependent manner. Moreover, a significant inhibitory effect of quinine on the formation of M4 was observed in microsomes obtained from control rats, isoniazid-induced rats, and β-naphthoflavone-induced rats. In contrast, α- naphthoflavone, cimetidine, and methylpyrazole had no inhibitory effects on this metabolic pathway. Conclusion: Imrecoxib is metabolized via 4'-methyl hydroxylation in rat liver microsomes. The reaction is mainly catalyzed by CYP 3A. CYP 2D also played a role in control rats, in isoniazid-induced rats and in β- naphthoflavone-induced rats.
Journal Article
Profiling PRMT methylome reveals roles of hnRNPA1 arginine methylation in RNA splicing and cell growth
2021
Numerous substrates have been identified for Type I and II arginine methyltransferases (PRMTs). However, the full substrate spectrum of the only type III PRMT, PRMT7, and its connection to type I and II PRMT substrates remains unknown. Here, we use mass spectrometry to reveal features of PRMT7-regulated methylation. We find that PRMT7 predominantly methylates a glycine and arginine motif; multiple PRMT7-regulated arginine methylation sites are close to phosphorylations sites; methylation sites and proximal sequences are vulnerable to cancer mutations; and methylation is enriched in proteins associated with spliceosome and RNA-related pathways. We show that PRMT4/5/7-mediated arginine methylation regulates hnRNPA1 binding to RNA and several alternative splicing events. In breast, colorectal and prostate cancer cells, PRMT4/5/7 are upregulated and associated with high levels of hnRNPA1 arginine methylation and aberrant alternative splicing. Pharmacological inhibition of PRMT4/5/7 suppresses cancer cell growth and their co-inhibition shows synergistic effects, suggesting them as targets for cancer therapy.
Arginine methyltransferases (PRMTs) are involved in the regulation of various physiological and pathological conditions. Using proteomics, the authors here profile the methylation substrates of PRMTs 4, 5 and 7 and characterize the roles of these enzymes in cancer-associated splicing regulation.
Journal Article