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Interband optical absorption in wurtzite GaN/InxGa1?xN/GaN spherical quantum dots with built-in electric field
摘要： Based on the principle of density matrix and the finite element method, the interband optical absorption between the electron and hole has been investigated in a wurtzite GaN/InxGa1?xN/GaN spherical core–shell quantum dot (CSQD) including a strong built-in electric field (BEF). We have studied the effects of the size and the ternary mixed crystal on the optical absorption coefficients (ACs) and refraction index changes (RICs). The results indicate that the absorption peaks of ACs and RICs decrease rapidly, and show a redshift with the increase of the component x. It is also found that the absorption peaks of ACs and RICs reduce obviously and depend on the core radius and the well width. When the core radius increases, the positions of the maximum ACs and RICs show a blueshift. At the same time, it presents a redshift when the well width increases. Particularly, the influence of the well width is much stronger than the core radius in the wurtzite GaN/InxGa1?xN/GaN spherical CSQDs. We hope that these results could provide guidance on both theoretical and experimental study related to the optical properties of spherical CSQDs.
关键词： Core–shell quantum dot,built-in electric field,optical property,ternary mixed crystal effect
更新于2025-09-12 10:27:22
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Investigation of AgInS2/ZnS Quantum Dots by Magnetic Circular Dichroism Spectroscopy
摘要： Over recent years, quantum dots (QDs) based on ternary metal dichalcogenides have attracted a lot of attention due to their unique properties and a range of potential applications. Here, we review the latest studies on the optical properties of AgInS2/ZnS QDs with emphasis on their theoretical modeling, and present our investigations of electronic transitions invisible in unstructured absorption spectra of AgInS2/ZnS QDs. The analysis of the absorption, photoluminescence excitation (PLE), and magnetic circular dichroism (MCD) spectra of hydrophobic and hydrophilic AgInS2/ZnS QDs of different sizes enables us to determine positions of electron transitions in these QDs. We demonstrate that the use of the second derivative of PLE spectra provides more unequivocal data on the position of the energy transitions compared with the second derivative of absorption spectra. Analysis of the MCD spectra reveals that the magnetic field induces energy level mixing in AgInS2/ZnS QDs in contrast to the traditional Cd-based QDs, where MCD is associated only with removing degeneracy of the excited energy level.
关键词： AgInS2/ZnS,electronic transitions,magnetic circular dichroism,AIS,ternary quantum dots
更新于2025-09-12 10:27:22
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Nonlinear optical properties and Q-switched laser application of a novel Mo<sub>0.5</sub>Re<sub>0.5</sub>S<sub>2</sub> ternary alloy material at 2 μm
摘要： In this study, a novel ternary alloy using Mo0.5Re0.5S2 as a saturable absorber (SA) is prepared by liquid phase separation method (LPE) and successfully applied to a passively Q-switched (PQS) Tm:YAP bulk laser for the first time. The nonlinear saturable absorption effect of the prepared Mo0.5Re0.5S2 SA at 2 μm is characterized using the open-aperture Z-scan technique and results in a saturable intensity of 5.62 μJ/cm2 and modulation depth of 7.92%. Using Mo0.5Re0.5S2 as an SA, a 2 μm Q-switched Tm:YAP laser is realized, generating a maximum output power of 0.957 W with a shortest pulse width of 857.5 ns and a maximum repetition rate of 95 kHz. The corresponding single pulse energy and peak power are 10.1 μJ and 11.5 W, respectively. These achievements indicate that Mo0.5Re0.5S2 could be an excellent and reliable SA for mid-infrared laser applications, and the ternary transition metal disulfide alloy will bring new application opportunities to optoelectronic devices in the future.
关键词： 2 μm,ternary alloy,Mo0.5Re0.5S2,Q-switched laser,saturable absorber
更新于2025-09-12 10:27:22
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Regulating the Phase Separation of Ternary Organic Solar Cells via 3D Architectured AIE Molecules
摘要： An optimized bulk heterojunction (BHJ) interface, certifying enhanced exciton-splitting, charge separation and recombination inhibition, is vastly desired to obtain high power conversion efficiencies (PCEs). Herein, the ternary strategy has been employed to effectively modify the phase separation between the J71:ITIC blend by incorporating a 3D aggregation-induced emission (AIE) material, Tetraphenylethylene (TPE). Hence, as a consequence of improved charge mobility, lower bimolecular recombination and enhanced fill factor (FF), an excellent PCE of 12.16% has been achieved; a 21.23% increment over the PCE of binary devices. Likewise, Flory-Huggins parameter (c ) and surface free energy analysis reveals a high degree of miscibility between J71 and TPE, that leads to a rearrangement at the D-A interface such that TPE settles in between the D and A and thus forces the ITIC away from J71 and out of the mixed phase, indicating relatively higher average acceptor domain purity at the interface and ultimately better FF and PCE for the ternary devices. Likewise, TPE inclusion in various other fullerene and nonfullerene systems also leads to similar results, signifying this to be an effective methodology to boost the PCEs of the organic solar cells, especially for the systems with low FF.
关键词： energy transfer,aggregation-induced emission,3D molecule,ternary organic solar cells,bulk heterojunction interface,phase separation
更新于2025-09-12 10:27:22
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Bandgap Tunable Ternary Cd <sub/><i>x</i> </sub> Sb <sub/> 2– <i>y</i> </sub> S <sub/>3?δ</sub> Nanocrystals for Solar Cell Applications
摘要： We report the synthesis and photovoltaic performance of a new nonstoichiometric ternary metal sulfide alloyed semiconductor?CdxSb2?yS3?δ nanocrystals prepared by the two-stage sequential ionic layer adsorption reaction technique. The synthesized CdxSb2?yS3?δ nanocrystals retain the orthorhombic structure of the host Sb2S3 with Cd substituting a fraction (x = 0?0.15) of the cationic element Sb. The CdxSb2?yS3?δ lattice expands relative to the host, Sb2S3, with its lattice constant a increasing linearly with Cd content x. Optical and external quantum efficiency (EQE) spectra revealed that the bandgap Eg of CdxSb2?yS3?δ decreased from 1.99 to 1.69 eV (i.e., 625?737 nm) as x increased from 0 to 0.15. Liquid-junction CdxSb2?yS3?δ quantum dot-sensitized solar cells were fabricated using the polyiodide electrolyte. The best cell yielded a power conversion efficiency (PCE) of 3.72% with the photovoltaic parameters of Jsc = 15.97 mA/cm2, Voc = 0.50 V, and FF = 46.6% under 1 sun. The PCE further increased to 4.86%, a respectable value for a new solar material, under a reduced light intensity of 10% sun. The PCE (4.86%) and Jsc (15.97 mA/cm2) are significantly larger than that (PCE = 1.8%, Jsc = 8.55 mA/cm2) of the Sb2S3 host. Electrochemical impedance spectroscopy showed that the ZnSe passivation coating increased the electron lifetime by three times. The EQE spectrum of CdxSb2?yS3?δ has a maximal EQE of 82% at λ = 350 nm and covers the spectral range of 300?750 nm, which is significantly broader than that (300?625 nm) of the Sb2S3 host. The EQE-integrated current density yields a Jph of 11.76 mA/cm2. The tunable bandgap and a respectable PCE near 5% suggest that CdxSb2?yS3?δ could be a potential candidate for a solar material.
关键词： ternary metal sulfide,CdxSb2?yS3?δ nanocrystals,photovoltaic performance,quantum dot-sensitized solar cells,bandgap tunable
更新于2025-09-12 10:27:22
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Highly-Crystalline Near-Infrared Acceptor Enabling Simultaneous Efficiency and Photostability Boosting in High-Performance Ternary Organic Solar Cells
摘要： The near-infrared (NIR) absorbing fused-ring electron acceptor, COi8DFIC, has demonstrated very good photovoltaic performance when combined with PTB7-Th as donor in binary organic solar cells (OSCs). In this work, the NIR acceptor was added to state-of-the art PBDB-T-2F:IT-4F-based solar cells as a third component, leading to: (i) an efficiency increase of the ternary devices compared to the binary solar cells in the presence of the highly-crystalline COi8DFIC acceptor and (ii) much improved photostability under 1-sun illumination. The electron transport properties were investigated and revealed the origin of the enhanced device performance. Compared to the binary cells, the optimized ternary PBDB-T-2F:COi8DFIC:IT-4F blends exhibit improved electron transport properties in the presence of 10% COi8DFIC, which is attributed to improved COi8DFIC molecular packing. Furthermore, transient absorption spectroscopy revealed slow recombination of charge carriers in the ternary blend. The improved electron transport properties were preserved in the ternary OSC upon aging, while in the binary devices they seriously deteriorated after simulated 1-sun illumination of 240 hours. Our work demonstrates a simple approach to enhance both OSC efficiency and photostability.
关键词： near-infrared acceptor,organic solar cell,ternary solar cell,photostability
更新于2025-09-12 10:27:22
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Ternary Polymer Solar Cells Facilitating Improved Efficiency and Stability
摘要： The use of a ternary active layer offers a promising approach to enhance the power conversion efficiency (PCE) of polymer solar cells (PSCs) via simply incorporating a third component. Here, a ternary PSC with improved efficiency and stability facilitated by a new small molecule IBC-F is demonstrated. Even though the PBDB-T:IBC-F-based device gives an extremely low PCE of only 0.21%, a remarkable PCE of 15.06% can be realized in the ternary device based on PBDB-T:IE4F-S:IBC-F with 20% IBC-F, which is ≈10% greater than that (PCE = 13.70%) of the control binary device based on PBDB-T:IE4F-S. The improvement in the device performance of the ternary PSC is mainly attributed to the enhancement of fill factor, which is due to the improved charge dissociation and extraction, suppressed bimolecular and trap-assisted recombination, longer charge-carrier lifetime, and enhanced intermolecular interactions for preferential face-on orientation. Additionally, the ternary device with 20% IBC-F shows better thermal and photoinduced stability over the control binary device. This work provides a new angle to develop the third components for building ternary PSCs with enhanced photovoltaic performance and stability for practical applications.
关键词： power conversion efficiency,stability,fill factor,ternary polymer solar cells
更新于2025-09-12 10:27:22
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Functionalized and reduced graphene oxide as hole transport layer and for use in ternary organic solar cell
摘要： Here is reported the performance of organic solar cells (OSCs) by using a new graphene oxide derivative as hole transport layer (HTL). OSCs are based on the PTB7:PC71BM blend as active layer and the alternative top electrode Field’s metal (Bi/In/Sn: 32.5%, 51%, 16.5%), which can be easily deposited through a vacuum-free process at regular atmosphere and low temperature (90°C). Graphene oxide (GO) was chemically functionalized and reduced with pentafluorophenylhydrazine, this fluorinated reduced graphene oxide (F5-rGO) was suspended in dimethylformamide for easy deposit by wet techniques such as spin-cast. F5-rGO has a work-function of 5.1 eV due to the high electronegativity of fluorine atoms incorporated into the GO sheets. The best achieved PCE of the OSCs fabricated for a single layer of F5-rGO was 5.82%. An enhanced PCE of 7.67% when F5-GO was used as interlayer between ITO and PEDOT:PSS was reached (PCE of PEDOT:PSS-based was 7.29%). Additionally, functionalized and reduced (chemically) graphene oxide (H5-rGO) was also obtained from GO treated with phenylhydrazine, and ternary OSCs were also prepared by adding H5-rGO to the PTB7:PC71BM blend at different weight ratios: 0, 3, and 6%. The best results were achieved with 3% of H5-rGO: OSCs presented a PCE of 7.56%.
关键词： Functionalized-reduced graphene oxide,PTB7:PC71BM,Hole transport layer,Ternary OSCs,Organic solar cells
更新于2025-09-11 14:15:04
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Energetic Disorder and Activation Energy in Efficient Ternary Organic Solar Cells with Nonfullerene Acceptor Eh‐IDTBR as the Third Component
摘要： Solution processed ternary organic solar cells (OSCs) contain a third component in the active layer besides the donor/acceptor materials. Two main avenues are considered to fabricate ternary OSCs: (i) to improve the short circuit current density by the selected third component that can broaden and/or enhance the absorption of the host films; (ii) to increase the fill factor by adding materials with diverse crystallinity to tune the film morphology. However, little work has been reported for the improvement of open circuit voltage (VOC), energetic disorder, charge transfer state energy (ECT), and activation energy in ternary OSCs. Herein, we used ternary OSCs with active layer composed of PCE10: F8IC: Eh-IDTBR as model to examine these parameters besides the morphology. We found in the ternary device that the additional Eh-IDTBR improved the crystallinity of the acceptor phase in the ternary mixture; the VOC was 58 mV higher than that of the reference caused by the reduced energetic disorder; due to the good miscibility of Eh-IDTBR with both PCE10 and F8IC, only 50 meV in ECT was observed; zero field activation energy was lower than that for the reference. Our findings provide an alternative way to understand the complex ternary structural-electrical properties correlations.
关键词： ternary organic solar cells,charge transfer state energy,crystallinity phase,energetic disorder,activation energy
更新于2025-09-11 14:15:04
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High-Performance Ternary Organic Solar Cells Enabled by Combining Fullerene and Nonfullerene Electron Acceptors
摘要： Recently, by elaborately designing nonfullerene acceptors and selecting suitable polymer donors great progresses have been made towards binary organic solar cells (OSCs) with power conversion efficiencies (PCEs) over 15%. Ternary organic photovoltaics by introducing a third component into the host binary system is recognized to be highly effective to elevate the performance through extending the light absorption, manipulating the recombination behavior of the carriers, and improving the morphology of the active layer. In this work, we synthesized a new electron-acceptor ZITI-4F matching it with the wide-bandgap polymer donor PBDB-T The PBDB-T:ZITI-4F-based OSC showed a high PCE of 12.33%. After introducing 40% of PC71BM as the third component, the ternary device achieved an improved PCE of 13.40% with simultaneously improved photovoltaic parameters. The higher performance of the ternary device can be attributed to the improved and more balanced charge mobility, reduced bimolecular recombination, and more favorable morphology. These results indicate that the cooperation of a fullerene-based acceptor and a nonfullerene acceptor to fabricate ternary OSCs is an effective approach to optimizing morphology and therefore to increase the performance of OSCs.
关键词： ternary organic solar cells,power conversion efficiencies,indenoin-dene,electron acceptors
更新于2025-09-11 14:15:04