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Review on III-V Semiconductor Single Nanowire-Based Room Temperature Infrared Photodetectors
摘要： Recently, III-V semiconductor nanowires have been widely explored as promising candidates for high-performance photodetectors due to their one-dimensional morphology, direct and tunable bandgap, as well as unique optical and electrical properties. Here, the recent development of III-V semiconductor-based single nanowire photodetectors for infrared photodetection is reviewed and compared, including material synthesis, representative types (under different operation principles and novel concepts), and device performance, as well as their challenges and future perspectives.
关键词： nanowire,III-V semiconductor,infrared photodetector
更新于2025-09-23 15:19:57
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Homoleptic mer-Ir(III) complexes for highly efficient solution-processable green phosphorescent organic light-emitting diodes with high current efficiency
摘要： Two new highly efficient homoleptic green-emitting meridional iridium (III) complexes namely, mer-tris[5-hexyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin-6-one]iridium(III) (mer-Ir1) and mer-tris[5-ethylhexyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin-6-one]iridium(III) (mer-Ir2) were designed and synthesized at high temperature. These new Ir(III) complexes consist of amide bridged trifluoromethyl substituted phenylpyridine skeleton with longer alkyl chain. Interestingly, both Ir(III) complexes, mer-Ir1 and mer-Ir2 show bright green emission (λmax = 528 nm) with high photoluminescence quantum yields of 42 and 51% in solution at room temperature, respectively. Their thermal, photophysical, electrochemical, and electroluminescent (EL) properties were fully investigated. Both complexes were used as dopants for solution-processed green phosphorescence organic light-emitting diodes (PHOLEDs). Notably, the device using mer-Ir2 as new green dopant exhibited excellent EL performance with a maximum external quantum efficiency of 20.03% and maximum current efficiency of 67.81 cd A-1. To the best of our knowledge, this is the first time, particularly Ir(C^N)3 based mer-Ir(III) isomers showing excellent EL performance with high luminous efficiency in the green region via solution-processed PHOLEDs has been reported.
关键词： high photoluminescence quantum yields,current efficiency,external quantum efficiency,homoleptic green-emitting meridional iridium (III) complexes,solution-processed green phosphorescence organic light-emitting diodes (PHOLEDs)
更新于2025-09-23 15:19:57
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High-Speed MOVPE Growth of InGaP Solar Cells
摘要： Impacts of reactor pressure and growth temperature on the qualities and properties of InGaP epitaxial layers grown in a narrow-channel horizontal metalorganic vapor-phase epitaxy (MOVPE) reactor were investigated with a growth rate of 10 μm/h. The roughness of InGaP was improved remarkably when the pressure was increased from 6 to 10 and 15 kPa. The reason is most likely related to the absolute pressure of P and the migrations of In and Ga adatoms on the wafer surface. Owing to the gas-phase reactions and desorption of P from InGaP, the surface of InGaP became rough, and the pit dislocation was increased with an increase in growth temperature. Although a low temperature was beneficial in order to obtain a smooth InGaP surface, the carrier lifetime in InGaP was shortened as a drawback. Consequently, InGaP n-on-p solar cells grown at a low temperature suffered from the degradations of both short-circuit current density and open-circuit voltage. Background impurities and defect densities in low temperature grown InGaP were attributed to these deteriorations. At the optimized growth temperature of 650 °C and the reactor pressure of 15 kPa, the growth rate of InGaP was accelerated to 20 and 30 μm/h. InGaP solar cells were successfully fabricated with the rate of 30 μm/h that opened up the way for the fabrication of III–V multijunction solar cells in the high-speed MOVPE reactor.
关键词： III–V semiconductor materials,semiconductor growth,photovoltaic cells
更新于2025-09-23 15:19:57
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Diastereoselective Photooxidation and Reduction of Chiral Iridium(III) Complexes
摘要： A diastereoselective photooxidation of α-amino acid (AA) complexes into imino acid complexes using a chiral iridium(III) complex as a photosensitizer and stereo-controller under visible light irradiation and oxygen was developed. It was found that the oxidative rate of Δ-[Ir(pq)2(L-AA)] (pq is 2-phenylquinoline) diastereomer is significantly higher than that of the corresponding Δ-[Ir(pq)2(D-AA)] diastereomer, providing a new protocol for kinetic resolution of AAs via a nonenzymatic pathway. Moreover, the thermodynamic controlled strategy offered a complemental method for the diastereoselective hydrogenation of imine bonds using NaBH4 as a reductant under the chiral Ir(III) complex as a stereo-controller. The combination of diastereoselective photooxidation and reduction processes results in a new protocol for deracemization of α-amino acids under mild conditions. Mechanism study strongly indicates that singlet oxygen is a key participant in the reaction and the α-C?H bond cleavage of AAs is the rate-determining step.
关键词： kinetic resolution,diastereoselective photooxidation,chiral iridium(III) complex,deracemization,α-amino acids
更新于2025-09-23 15:19:57
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Simultaneously photocatalytic redox and removal of chromium(VI) and arsenic(III) by hydrothermal carbon-sphere@nano-Fe3O4
摘要： The coexistence of multiple-component contaminants, such as Cr(VI) and As(III) in acid mineral drainage, brings more difficulties in the wastewater treatment. This study developed a novel strategy for simultaneous redox conversion and removal of Cr(VI) and As(III) in solution. By employing iron oxide encapsulated in hydrothermal carbon sphere (HCS@Fe3O4), the synergistic photocatalytic reduction of Cr(VI) and oxidation of As(III) were markedly accelerated under simulated solar light irradiation. The transformed Cr(III) and As(V) were readily removed by forming Cr(OH)3 and FeAsO4 precipitates. The Fe(III)/Fe(II) cycle in the system, which was greatly reinforced by photocatalysis in the presence of HCS@Fe3O4, has been demonstrated to be critical in the redox of Cr(VI) and As(III). It can keep sufficient Fe(II) in solution to both directly reduce Cr(VI) and promote the generation of ?OH for the oxidation of As(III). These findings provide an effectively synergistic conversion and removal strategy for implications in multiple-contaminated water treatment.
关键词： chromium(VI),carbon sphere@Fe3O4,photocatalytic redox,arsenic(III)
更新于2025-09-19 17:15:36
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Understanding the Citric Acid-Urea Co-Directed Microwave Assisted Synthesis and Ferric Ion Modulation of Fluorescent Nitrogen Doped Carbon Dots: A Turn On Assay for Ascorbic Acid
摘要： Herein, nitrogen doped carbon dots (NCDs) were synthesised from citric acid and urea via a previously reported microwave assisted route. The NCDs shows emission maximum at 500 nm on excitation at 400 nm. The fluorescence of NCDs decreases slightly with increase in basicity of solution up to pH 7.5 and then increases again after pH 8.5, along with a blue-shift in tested alkaline pH. This pH dependent blue-shift indicates the presence of both carboxyl?carboxylate and phenol?phenolate prototropic equilibrium in NCDs. Due to the special interaction of these phenolates and carboxylates on NCDs surface with di- or tri- valent heavy transition metal ions; it is demonstrated that ferric ion (Fe3 + ion) can quench the fluorescence of NCDs. This Fe3 + induced static quenching of NCDs is a collaborative effect of inner filter effect, aggregation and ferromagnetism. However, Ascorbic acid (AA) can recover the fluorescence of Fe3 + quenched NCD with detection limit as low as 96 μM. This detection strategy has good selectivity towards AA over other antioxidants, saccharides, proteins and neurotransmitters. Furthermore, (spiked) human serum and (spiked) human urine were analysed and found good recovery percentage.
关键词： Fluorescence,Ascorbic Acid,Biosensor,Inner Filter Effect,Iron(III),Carbon Dots
更新于2025-09-19 17:15:36
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The influence of molecular structure on collision radius for optical sensing of molecular oxygen based on cyclometalated Ir( <scp>iii</scp> ) complexes
摘要： Three triphenylamine (TPA) substituted cyclometalated Ir(III) complexes IrA1, IrA2, and IrA3 based on Ir(ppy)3 were synthesized and applied as phosphorescent probes for the monitoring of molecular oxygen. The phosphorescence intensity of all the Ir(III) complexes in tetrahydrofuran (THF) was gradually quenched with an increase of oxygen concentration. The increase of TPA substituents on the meta-position of 2-phenylpyridine (IrA1-IrA3) gradually improved the oxygen sensitivity of cyclometalated Ir(III) complexes. IrA3 showed the highest oxygen sensitivity in THF with a KappSV of 204.8 bar?1 and a limit of detection (LOD) of 0.27 mbar. The relationship between molecular structure and the collision radiuses (s) of all the Ir(III) complexes has been investigated on the basis of the Demas model and the fundamental expression of luminescence quenching systems by oxygen. The ratio of collision radiuses are sIrA1/sIr(ppy)3 = 1.27 ± 0.05, sIrA2/sIr(ppy)3 = 1.72 ± 0.10, and sIrA3/sIr(ppy)3 = 2.13 ± 0.07, respectively. The introduction and increase of TPA substituents can obviously increase the collision radiuses of cyclometalated Ir(III) complexes which leading to potential oxygen sensitivity. And the incremental effect of collision radiuses caused by the introduction of TPA substituents resulted in outstanding oxygen sensitivity of IrA3. The results demonstrate for the first time evidence between molecular structure and oxygen sensitivity of the emitters for optical sensing.
关键词： optical sensing,collision radius,molecular oxygen,triphenylamine substituents,cyclometalated Ir(III) complexes
更新于2025-09-19 17:15:36
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Investigation on the photophysical properties of a series of promising phosphorescent iridium (III) complexes with modified cyclometalating ligands
摘要： Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were applied to investigate the electronic structures and photophysical properties of a series of phosphorescent iridium (III) complexes, [(C^N)2Ir(N^N)]+(PF6)(cid:2), in which C^N = 4-aryl-1-benzyl-1H-1, 2, 3-triazoles. Herein, aryl = phenyl, biphenyl, three-phenyl aromatic for complexes 1a, 2a, 3a (N^N = 2, 20-bipyridine) and aryl = 40, 60-di?uorophenyl, 60-?uoro-biphenyl, 60-?uoro-three-phenyl aromatic for complexes 1b, 2b, 3b (N^N = 4, 40-di-tert-butyl-2, 20-bipyridine), respectively. The geometric/electronic con?gurations, absorption/emission properties and phosphorescent performances have been outlined for each of the complexes. Based on the two simpli?cations presented in this paper and the available experimental data, the phosphorescent radiative rates for complexes 1a-3b were approximately obtained to be: 1.20 (cid:3) 106 s(cid:2)1, 1.68 (cid:3) 105 s(cid:2)1, 2.19 (cid:3) 107 s(cid:2)1, 3.85 (cid:3) 106 s(cid:2)1, 1.85 (cid:3) 107 s(cid:2)1 and 1.50 (cid:3) 107 s(cid:2)1, respectively. In view of the electroluminescent applications in OLED, our present research work is of great importance for the design and synthesis of organo-transition metal complexes with improved phosphorescent performances.
关键词： Phosphorescence,Photophysical properties,Time-dependent DFT,Iridium (III) complexes,Density functional theory (DFT)
更新于2025-09-19 17:15:36
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A ratiometric fluorescent sensor for sensitive detection of UDG using poly(thymine)-templated copper nanoclusters and DAPI with exonuclease III assisted amplification
摘要： As one of critical base excision repair enzymes, uracil-DNA glycosylase (UDG) can specifically repair uracil-induced DNA damage to maintain the genome integrity of organisms. Moreover, abnormal expression of UDG is related to various cancers and other serious diseases. Therefore, it is essential to accurately and sensitively monitor UDG activity. In this work, a ratiometric fluorescence method using poly-(thymine) DNA template copper nanoclusters (Cu NCs) and 4',6-diamidino-2-phenylindole (DAPI) as the output signals is developed for simple, selective, and sensitive detection of UDG. A double-stranded DNA (dsDNA) consisting of a uracil-containing single chain and a trigger sequence is designed as a substrate dsDNA. Meanwhile, another dsDNA comprising 30 pairs of A-T bases ((AT)30 dsDNA) is designed to be partially complementary to the trigger chain. The (AT)30 dsDNA itself has no blunt or recessed 3’ end and cannot be cut by exonuclease III (Exo III). With the Exo III-assisted amplification, adding UDG results in the success synthesis of red-emissive Cu NCs, while the dsDNAs in the system are hydrolyzed and the fluorescence signal of DAPI is weak. In contrast, without addition of UDG, the fluorescence intensity of Cu NCs is low, while the DAPI emits significantly enhanced fluorescence signal. The proposed method presents a detection limit of 5.0 × 10?5 U mL-1 and can be applied to the Hela cell lysate sample with satisfactory results. Additionally, the kinetic parameter is studied and the UDG inhibition effect is evaluated. In summary, this work provides a potential platform for DNA repair enzyme-related analysis and clinical diagnosis.
关键词： Uracil-DNA glycosylase,Ratiometric fluorescent sensor,Poly-(thymine) templated copper nanoclusters,DAPI,Exo III-assisted amplification
更新于2025-09-19 17:15:36
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Absorption of light in a single vertical nanowire and a nanowire array
摘要： Both a single III–V semiconductor nanowire and an array of such nanowires have shown promise for solar cell applications. However, the correspondence between the optical properties of the single nanowire and the nanowire array has not been studied. Here, we perform electromagnetic modeling of InP nanowires to study this relationship. We find that a single nanowire can show at an absorption peak, a remarkably high absorption cross-section that is more than 50 times the geometrical cross-section. With optimization of the diameter of the single nanowire, the short-circuit current density is 30 times higher than in a bulk solar cell. With such a strong absorption, we predict an apparent efficiency >500% for the single nanowire solar cell. In contrast, we show that an efficient nanowire array solar cell cannot rely on strong absorption just through the absorption peak. Instead, the nanowires need to be packed rather closely to enhance the absorption of the full solar spectrum. At the optimum diameter for the nanowire array, neighboring nanowires compete strongly for absorption of incident photons at the absorption peak, which limits the absorption per nanowire by a factor of 18. As a result, the single InP nanowire is optimized at a diameter of 110 nm while the nanowires in the array are optimized at a considerably larger diameter of 180 nm. Importantly, we show analytically the coupling efficiency of incident light into the fundamental HE11 guided mode and consecutive absorption of the mode in the nanowires. With that analysis, we explain that a single nanowire shows two different absorption pathways—one through coupling into the guided mode and another by coupling into the nanowire through the sidewall. This analytical analysis also shows at which period the neighboring nanowires in an array start to compete for absorption of incident photons.
关键词： III–V semiconductor nanowire,optics modeling,absorption,solar cell
更新于2025-09-19 17:15:36