1
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Spectrometer based on a compact disordered multi-mode interferometer. OPTICS EXPRESS 2023; 31:12624-12633. [PMID: 37157418 DOI: 10.1364/oe.484199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present a compact, CMOS compatible, photonic integrated circuit (PIC) based spectrometer that combines a dispersive array element of SiO2-filled scattering holes within a multimode interferometer (MMI) fabricated on the silicon-on-insulator (SOI) platform. The spectrometer has a bandwidth of 67 nm, a lower bandwidth limit of 1 nm, and a peak-to-peak resolution of 3 nm for wavelengths around 1310 nm.
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2
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Laser-Assisted Ultrafast Fabrication of Crystalline Ta-Doped TiO 2 for High-Humidity-Processed Perovskite Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2022; 14:15141-15153. [PMID: 35330992 PMCID: PMC9098116 DOI: 10.1021/acsami.1c24225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/11/2022] [Indexed: 05/27/2023]
Abstract
A titanium dioxide (TiO2) compact film is a widely used electron transport layer (ETL) for n-i-p planar perovskite solar cells (PSCs). However, TiO2 sufferers from poor electrical conductivity, leading to high energy loss at the perovskite/ETL/transparent conductive oxide interface. Doping the TiO2 film with alkali- and transition-metal elements is an effective way to improve its electrical conductivity. The conventional method to prepare these metal-doped TiO2 films commonly requires time-consuming furnace treatments at 450-600 °C for 30 min to 3 h. Herein, a rapid one-step laser treatment is developed to enable doping of tantalum (Ta) in TiO2 (Ta-TiO2) and to simultaneously induce the crystallization of TiO2 films from its amorphous precursor to an anatase phase. The PSCs based on the Ta-TiO2 films treated with the optimized fiber laser (1070 nm) processing parameters (21 s with a peak processing temperature of 800-850 °C) show enhanced photovoltaic performance in comparison to that of the device fabricated using furnace-treated films at 500 °C for 30 min. The ambient-processed planar PSCs fabricated under high relative humidity (RH) of 50-70% display power conversion efficiencies (PCEs) of 18.34% and 16.04% for devices based on Cs0.1FA0.9PbI3 and CH3NH3PbI3 absorbers, respectively. These results are due to the improved physical and chemical properties of the Ta-TiO2 films treated by the optimal laser process in comparison to those for the furnace process. The laser process is rapid, simple, and potentially scalable to produce metal-doped TiO2 films for efficient PSCs.
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Manipulation of Molecular Vibrations on Condensing Er 3+ State Densities for 1.5 μm Application. J Phys Chem Lett 2021; 12:9620-9625. [PMID: 34585923 DOI: 10.1021/acs.jpclett.1c02691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Vibrational modes of chemical bonds in organic erbium (Er3+) materials play an important role in determining the efficiency of the 1.5 μm Er3+ emission. This work studies the energy coupling of the Er3+ intra-4f transitions and vibrational modes. The results demonstrate that the coupling introduces enormous nonradiative internal relaxation, which condenses the excited erbium population on to the 4I13/2 state. This suggests that vibrational modes can be advantageous for optimizing the branching ratio for the 1.5 μm transition in organic erbium materials. Through control of the quenching effect on to the 4I13/2 state and a reliable determination of intrinsic radiative rates, it is found that the pump power for population inversion can be reduced by an order of magnitude at high erbium concentrations compared to conventional inorganic erbium materials.
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Preparation of solution processed photodetectors comprised of two-dimensional tin(ii) sulfide nanosheet thin films assembled via the Langmuir-Blodgett method. RSC Adv 2021; 11:26813-26819. [PMID: 35479979 PMCID: PMC9037678 DOI: 10.1039/d1ra04470b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/30/2021] [Indexed: 01/09/2023] Open
Abstract
We report the manufacture of fully solution processed photodetectors based on two-dimensional tin(ii) sulfide assembled via the Langmuir-Blodgett method. The method we propose can coat a variety of substrates including paper, Si/SiO2 and flexible polymer allowing for a potentially wide range of applications in future optoelectronic devices.
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Synthesis of IR-emitting HgTe quantum dots using an ionic liquid-based tellurium precursor. NANOSCALE ADVANCES 2021; 3:4062-4064. [PMID: 36132826 PMCID: PMC9418010 DOI: 10.1039/d1na00291k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/24/2021] [Indexed: 06/16/2023]
Abstract
New scalable precursor chemistries for quantum dots are highly desirable and ionic liquids are viewed as an attractive alternative to existing solvents, as they are often considered green and recyclable. Here we report the synthesis of HgTe quantum dots with emission in the near-IR region using a phosphonium based ionic liquid, and without standard phosphine capping agents.
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Abstract
![]()
Hybrid
bismuth-containing halides are emerging as alternative candidates
to lead-containing perovskites for light-harvesting applications,
as Bi3+ is isoelectronic with Pb2+ and the presence of an active lone pair of electrons
is expected to result in outstanding charge-carrier transport properties.
Here, we report a family of one binary and three ternary iodobismuthates
containing 1,4-diazabicyclo[2.2.2]octane (DABCO). These materials
have been prepared solvothermally and their crystal structures, thermal
stability, and optical properties determined. Reactions carried out
in the presence of bismuth iodide and DABCO produced (C6H12N2)BiI3 (1), which
consists of hybrid ribbons in which pairs of edge-sharing bismuth
octahedra are linked by DABCO ligands. Short I···I
contacts give rise to a three-dimensional network. Similar reactions
in the presence of copper iodide produced (C8H17N2)2Bi2Cu2I10(2) and [(C6H13N2)2BiCu2I7](C2H5OH) (3) in which either ethylated DABCO cations (EtDABCO)+ or monoprotonated DABCO cations (DABCOH)+ are
coordinated to copper in discrete tetranuclear and trinuclear clusters,
respectively. In the presence of potassium iodide, a unique three-dimensional
framework, (C6H14N2)[(C6H12N2)KBiI6] (4), was
formed, which contains one-dimensional hexagonal channels approximately
6 Å in diameter. The optical band gaps of these materials, which
are semiconductors, range between 1.82 and 2.27 eV, with the lowest
values found for the copper-containing discrete clusters. Preliminary
results on the preparation of thin films are presented. The solvothermal syntheses, crystal structures, and optical
properties of four new iodobismuthates containing 1,4-diazabicyclo[2.2.2]octane
(DABCO) are described. In the absence of hydriodic acid, DABCO can
act as a ligand instead of acting as a countercation.
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Non-diffracting beam generated from a photonic integrated circuit based axicon-like lens. OPTICS EXPRESS 2021; 29:10480-10490. [PMID: 33820182 DOI: 10.1364/oe.419618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
We demonstrate an on-chip silicon-on-insulator (SOI) device to generate a non-diffracting beam of ≈850 µm length from a diffractive axicon-like lens etched using a low resolution (200 nm feature size, 250 nm gap) deep-ultraviolet lithographic fabrication. The device consists of circular gratings with seven stages of 1x2 multimode interferometers. We present a technique to apodize the gratings azimuthally by breaking up the circles into arcs which successfully increased the penetration depth in the gratings from ≈5 µm to ≈60 µm. We characterize the device's performance by coupling 1300±50 nm swept source laser in to the chip from the axicon and measuring the out-coupled light from a grating coupler. Further, we also present the implementation of balanced homodyne detection method for the spectral characterization of the device and show that the position of the output lobe of the axicon does not change significantly with wavelength.
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Loss of phenotypic inheritance associated with ydcI mutation leads to increased frequency of small, slow persisters in Escherichia coli. Proc Natl Acad Sci U S A 2020; 117:4152-4157. [PMID: 32029596 PMCID: PMC7049120 DOI: 10.1073/pnas.1914741117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Whenever a genetically homogenous population of bacterial cells is exposed to antibiotics, a tiny fraction of cells survives the treatment, the phenomenon known as bacterial persistence [G.L. Hobby et al., Exp. Biol. Med. 50, 281-285 (1942); J. Bigger, The Lancet 244, 497-500 (1944)]. Despite its biomedical relevance, the origin of the phenomenon is still unknown, and as a rare, phenotypically resistant subpopulation, persisters are notoriously hard to study and define. Using computerized tracking we show that persisters are small at birth and slowly replicating. We also determine that the high-persister mutant strain of Escherichia coli, HipQ, is associated with the phenotype of reduced phenotypic inheritance (RPI). We identify the gene responsible for RPI, ydcI, which encodes a transcription factor, and propose a mechanism whereby loss of phenotypic inheritance causes increased frequency of persisters. These results provide insight into the generation and maintenance of phenotypic variation and provide potential targets for the development of therapeutic strategies that tackle persistence in bacterial infections.
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Confinement Effects and Charge Dynamics in Zn 3N 2 Colloidal Quantum Dots: Implications for QD-LED Displays. ACS APPLIED NANO MATERIALS 2019; 2:7214-7219. [PMID: 32118200 PMCID: PMC7036766 DOI: 10.1021/acsanm.9b01714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/28/2019] [Indexed: 05/11/2023]
Abstract
Zinc nitride (Zn3N2) colloidal quantum dots are composed of nontoxic, low-cost, and earth-abundant elements. The effects of quantum confinement on the optical properties and charge dynamics of these dots are studied using steady-state optical characterization and ultrafast fluence-dependent transient absorption. The absorption and emission energies are observed to be size-tunable, with the optical band gap increasing from 1.5 to 3.2 eV as the dot diameter decreased from 8.9 to 2.7 nm. Size-dependent absorption cross sections (σ = 1.22 ± 0.02 × 10-15 to 2.04 ± 0.03 × 10-15 cm2), single exciton lifetimes (0.36 ± 0.02 to 0.65 ± 0.03 ns), as well as Auger recombination lifetimes of biexcitons (3.2 ± 0.4 to 5.0 ± 0.1 ps) and trions (20.8 ± 1.8 to 46.3 ± 1.3 ps) are also measured. The degeneracy of the conduction band minimum (g = 2) is determined from the analysis of the transient absorption spectra at different excitation fluences. The performance of Zn3N2 colloidal quantum dots thus broadly matches that of established visible light emitting quantum dots based on toxic or rare elements, making them a viable alternative for QD-LED displays.
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Solution Processable 1D Fullerene C 60 Crystals for Visible Spectrum Photodetectors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703624. [PMID: 29350479 DOI: 10.1002/smll.201703624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/17/2017] [Indexed: 05/15/2023]
Abstract
Visible spectrum photodetector devices fabricated using molecular crystals of carbon C60 are reported. The devices operate efficiently, extending over and beyond the full visible light spectrum (300-710 nm) with a bias voltage tunable responsivity of 4 mA-0.5 mA W-1 . Across this range of wavelengths, the noise equivalent power of these devices remains below 102 nW Hz-1/2 , providing a detectivity of 107 Jones. The noise current in these devices is found to have a strong dependence on both bias voltage and frequency, varying by 4 orders of magnitude from 1 nA Hz-1/2 to 0.1 pA Hz-1/2 . The devices also display a near-linear dependence of photocurrent on light intensity over 4 orders of magnitude, providing a dynamic range approaching 80 dB. The 3 dB bandwidth of the devices is found to be above 102 Hz, while the 18 dB bandwidth exceeds 1 kHz. The transient photocurrents of the devices have a rise time of ≈50 µs and a long fall time of ≈4 ms. The spectral photocurrent of the devices is found to quench gradually with a reduction in temperature from ≈300 K and is fully quenched at temperatures below T ≈ 100 K. Upon reheating, the device performance is fully recovered.
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11
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The Biosynthesis of Infrared-Emitting Quantum Dots in Allium Fistulosum. Sci Rep 2016; 6:20480. [PMID: 26857581 PMCID: PMC4746658 DOI: 10.1038/srep20480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 01/04/2016] [Indexed: 11/24/2022] Open
Abstract
The development of simple routes to emissive solid-state materials is of paramount interest, and in this report we describe the biosynthesis of infrared emitting quantum dots in a living plant via a mutual antagonistic reaction. Exposure of common Allium fistulosum to mercury and tellurium salts under ambient conditions resulted in the expulsion of crystalline, non-passivated HgTe quantum dots that exhibited emissive characteristics in the near-infrared spectral region, a wavelength range that is important in telecommunications and solar energy conversion.
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12
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The Role of Substituent Effects in Tuning Metallophilic Interactions and Emission Energy of Bis-4-(2-pyridyl)-1,2,3-triazolatoplatinum(II) Complexes. Angew Chem Int Ed Engl 2015; 54:7949-53. [DOI: 10.1002/anie.201502390] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Indexed: 11/11/2022]
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13
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The Role of Substituent Effects in Tuning Metallophilic Interactions and Emission Energy of Bis-4-(2-pyridyl)-1,2,3-triazolatoplatinum(II) Complexes. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502390] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Tuneable paramagnetic susceptibility and exciton g-factor in Mn-doped PbS colloidal nanocrystals. NANOSCALE 2014; 6:8919-8925. [PMID: 24966016 DOI: 10.1039/c4nr02336f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report on PbS colloidal nanocrystals that combine within one structure solubility in physiological solvents with near-infrared photoluminescence, and magnetic and optical properties tuneable by the controlled incorporation of magnetic impurities (Mn). We use high magnetic fields (B up to 30 T) to measure the magnetization of the nanocrystals in liquid and the strength of the sp-d exchange interaction between the exciton and the Mn-ions. With increasing Mn-content from 0.1% to 7%, the mass magnetic susceptibility increases at a rate of ∼ 10(-7) m(3) kg(-1) per Mn percentage; correspondingly, the exciton g-factor decreases from 0.47 to 0.10. The controlled modification of the paramagnetism, fluorescence and exciton g-factor of the nanocrystals is relevant to the implementation of these paramagnetic semiconductor nanocrystals in quantum technologies ranging from quantum information to magnetic resonance imaging.
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15
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Phase separation in garnet solid solutions and its effect on optical properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:6448-6452. [PMID: 23996703 DOI: 10.1002/adma.201302288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/05/2013] [Indexed: 06/02/2023]
Abstract
Phase behavior is studied in erbium-doped Y3 Al5 O12 (YAG) garnets synthesized by solid-state reactions. High resolution synchrotron XRD and SEM-EDX studies reveal phase separation at an erbium content between 8 and 50 at%, depending upon the processing conditions. Similar results are found in closely-related garnet systems. The phase separation has a striking effect on the optical properties of YAG:Er(3+) .
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16
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Reply to comment on 'Temperature dependent optical properties of PbS nanocrystals'. NANOTECHNOLOGY 2013; 24:288002. [PMID: 23792634 DOI: 10.1088/0957-4484/24/28/288002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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17
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On the analogy between photoluminescence and carrier-type reversal in Bi- and Pb-doped glasses. OPTICS EXPRESS 2013; 21:8101-8115. [PMID: 23571900 DOI: 10.1364/oe.21.008101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Reaction order in Bi-doped oxide glasses depends on the optical basicity of the glass host. Red and NIR photoluminescence (PL) bands result from Bi(2+) and Bin clusters, respectively. Very similar centers are present in Bi- and Pb-doped oxide and chalcogenide glasses. Bi-implanted and Bi melt-doped chalcogenide glasses display new PL bands, indicating that new Bi centers are formed. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi(2+) and Bi clusters.
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Facile synthesis of titania nanowires via a hot filament method and conductometric measurement of their response to hydrogen sulfide gas. ACS APPLIED MATERIALS & INTERFACES 2013; 5:1197-1205. [PMID: 23327919 DOI: 10.1021/am302655j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Titania nanostructures are of increasing interest for a variety of applications, including photovoltaics, water splitting, and chemical sensing. Because of the photocatalytical properties of TiO₂, chemical processes that occur at its surface can be exploited for highly efficient nanodevices. A facile and fast synthesis route has been explored that is free of catalysts or templates. An environmental scanning electron microscopy (ESEM) system was employed to grow titania nanowires (NWs) in a water vapor atmosphere (∼1 mbar) and to monitor the growth in situ. In addition, the growth process was also demonstrated using a simple vacuum chamber. In both processes, a titanium filament was heated via the Joule effect and NWs were found to grow on its surface, as a result of thermal oxidation processes. A variety of nanostructures were observed across the filament, with morphologies changing with the wire temperature from the center to the end points. The longest NWs were obtained for temperatures between ∼730 °C and 810 °C. Typically, they have an approximate thickness of ∼300 nm and lengths of up to a few micrometers. Cross sections prepared by focused-ion-beam milling revealed the presence of a porous layer beneath the NW clusters. This indicates that the growth of NWs is driven by oxidation-induced stresses in the subsurface region of the Ti filament and by enhanced diffusion along grain boundaries. To demonstrate the potential of titania NWs grown via the hot filament method, single NW devices were fabricated and used for conductometric sensing of hydrogen sulfide (H₂S) gas. The NW electric resistance was found to decrease in the presence of H₂S. Its variation can be explained in terms of the surface depletion model.
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Abstract
A comprehensive study of the optical properties of PbS nanocrystals (NCs) is reported that includes the temperature dependent absorption, photoluminescence (PL) and PL lifetime in the range of 3-300 K. The absorption and PL are found to display different temperature dependent behaviour though both redshift as temperature is reduced. This results in a temperature dependent Stokes shift which increases from ∼75 meV at 300 K with reducing temperature until saturating at ∼130 meV below ∼150 K prior to a small reduction to 125 meV upon cooling from 25 to 3 K. The PL lifetime is found to be single exponential at 3 K with a lifetime of τ(1) = 6.5 μs. Above 3 K biexponential behaviour is observed with the lifetime for each process displaying a different temperature dependence. The Stokes shift is modelled using a three-level rate equation model incorporating temperature dependent parameter values obtained via fitting phenomenological relationships to the observed absorption and PL behaviour. This results in a predicted energy difference between the two emitting states of ∼6 meV which is close to the excitonic exchange energy splitting predicted theoretically for these systems.
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Comment on 'Unconventional gap state of trapped exciton in lead sulfide quantum dots'. NANOTECHNOLOGY 2011; 22:238001-238002. [PMID: 21483050 DOI: 10.1088/0957-4484/22/23/238001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In a recent paper (Lewis et al 2010 Nanotechnology 21 45502) proposed a previously unidentified gap state within lead sulfide nanocrystals (PbS-NCs) based on analysis of their temperature dependent optical properties. In the following we argue that due to oversights in the analysis of the data presented, inconsistencies arise which question their exclusion of 'dark' excitonic states as the origin of the observed effects.
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Optimization of hybrid organic-inorganic interdigitated photovoltaic device structure using a 2D diffusion model. ACS NANO 2011; 5:3069-3078. [PMID: 21425859 DOI: 10.1021/nn200197f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
To improve the efficiency of organic photovoltaic devices the inclusion of semiconducting nanoparticles such as PbS has been used to enhance near-infrared absorption. Additionally the use of interdigitated heterojunctions has been explored as a means of improving charge extraction. In this paper we provide a two-dimensional model taking into account these approaches with the aim of predicting an optimized device geometry to maximize the efficiency. The steady-state exciton population has been calculated in each of the active regions taking into account the full optical response based on using a finite difference approach to obtain approximate numerical solutions to the 2D exciton diffusion equation. On the basis of this we calculate the contribution of each active material to the device short circuit current and power conversion efficiency. We show that optimized structures can lead to power conversions efficiencies of ∼50% compared to a maximum of ∼17% for planar heterojunction devices. To achieve this the interdigitated region thickness should be ∼800 nm with PbS and C(60) widths of ∼60 and 20 nm, respectively. Even modest nanopatterning using much thinner active regions provides improvements in efficiency and may be approached using a variety of methods including nanoimprinting lithography, nanotemplating, or the incorporation of presynthesized nanorod structures.
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Efficient white light emission by upconversion in Yb3+-, Er3+- and Tm3+-doped Y2BaZnO5. Chem Commun (Camb) 2011; 47:6263-5. [DOI: 10.1039/c1cc11427a] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Synthesis and optical characterization of infra-red emitting mercury sulfide (HgS) quantum dots. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm10363f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Oxide phosphors for efficient light upconversion: Yb3+ and Er3+ co-doped Ln2BaZnO5 (Ln = Y, Gd). ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c000127a] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Charge transfer in hybrid organic–inorganic PbS nanocrystal systems. Phys Chem Chem Phys 2010; 12:7371-7. [DOI: 10.1039/c003179h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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The fabrication and analysis of a PbS nanocrystal:C(60) bilayer hybrid photovoltaic system. NANOTECHNOLOGY 2009; 20:245202. [PMID: 19468169 DOI: 10.1088/0957-4484/20/24/245202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A near-infrared sensitive hybrid photovoltaic system between PbS nanocrystals (PbS-NCs) and C(60) is demonstrated. Up to 0.44% power conversion efficiency is obtained under AM1.5G with a short circuit current density (J(sc)) of 5 mA cm(-2) when the PbS-NC layer is treated in anhydrous methanol. The observed J(sc) is found be approximately one-third of the maximum expected from this hybrid configuration, indicating the potential for further optimization. Crucial for device operation, a smooth film of nanocrystals is seen to form on the hole transporting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer deposited on the transparent electrode, facilitated through an ionic interaction between nanocrystal capping ligands and the PEDOT:PSS. The formation of the open circuit voltage in this system is seen to be influenced by an interfacial dipole formed at the hole-extracting electrode, providing insights for further optimization.
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Abstract
Organic-inorganic hybrid heterojunctions have potential as the basis for future photovoltaic devices. Herein, we report the results of investigations exploring the possibility of using pentacene and tetracene as photoelectron donors in conjunction with PbS nanocrystals (PbS-NCs). Photoinduced charge transfer was probed using external quantum efficiency measurements on acene:PbS-NC hybrid photovoltaic devices in conjunction with photoluminescence studies of the corresponding bilayer films. It is shown that photoelectron transfer from pentacene to the PbS-NCs is inefficient as compared to that between tetracene and PbS-NCs. The latter case can be rationalized in terms of the energy level alignment at the heterojunction assuming a common vacuum level. However, in the case of pentacene:PbS-NC junctions an interfacial energy level shift must be considered in order to explain the observations.
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28
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Controlled growth of true nanoscale single crystal fullerites for device applications. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b802417k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Modified Dipicolinic Acid Ligands for Sensitization of Europium(III) Luminescence. Inorg Chem 2006; 45:1739-44. [PMID: 16471988 DOI: 10.1021/ic051461u] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of substitution at the 4 and 3,5 positions in the pyridine ring of europium(III) pyridine-2,6-dicarboxylate complexes has been investigated with particular emphasis on sensitization of the Eu3+ ion. Sensitization of the Eu3+ 615-nm emission was achieved through excitation of the ligands in which the 4 substituent was -H, -OH, and -Cl and the 3,5 position was -H. In these cases, the ligand-to-Eu3+ ratio was confirmed as being 3:1. The sensitization was found to increase following substitution of the 4 position in the order Cl > H > OH. This is attributed to energy transfer occurring from the ligands into different Eu3+ intra-atomic energy levels, with spin selection rules governing the efficiency of this process. The Eu3+ luminescence lifetime was measured and found to vary from 1.16 to 2.90 ms depending on the excitation energy, ligand, and solvent. For the case of the 3,5-dibromo-4-hydroxy derivative, no sensitization was observed and a ligand-to-Eu3+ ratio of 1:1 was found. The solubility of these complexes in water and their long emission lifetime make them attractive for use as probes in biological systems.
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Structural and optoelectronic properties of C60 rods obtained via a rapid synthesis route. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b609074e] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Extreme hypersensitivity observed from 6H15/2↔6F11/2 transition of Dy3+ in inorganic noncrystalline solids. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.12.108] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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