- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Enhanced Fluorescence Emission and Magnetic Alignment Control of Biphasic Functionalized Composite Janus Particles
摘要： Janus particles, particles that have two distinct aspects on their surface or interiors, have attracted much attention due to their potential for application. For the application of Janus particles to high-resolution displays, and as light sources for optical circuits and fluorescent probes, the Janus particles should be nanosize to ensure high-resolution display and analysis, responsive to external stimuli, and highly fluorescent. However, it is still a challenging issue to develop such highly fluorescent nanoscale Janus particles and control their alignment. Magnetoresponsive Janus particles, of which the orientation can be controlled by an external magnetic field, are prepared by the simple introduction of polymer-coated magnetic nanoparticles (NPs) into the hemispheres of Janus particles. If these magnetoresponsive Janus particles can be combined with a strong fluorescence system, then they could be ideal candidates as components of the previously mentioned applications. In the present study, Janus particles are prepared with a fluorescent dye and gold nanoparticles (Au NPs) on one side. The optical properties of the resulting particles are assessed and discussed. Furthermore, the response of composite Janus particles containing dyes, Au NPs, and iron oxide NPs to an external magnetic field is discussed.
关键词： fluorescence enhancement,LSPR,magnetic alignment,Janus particles
更新于2025-09-23 15:21:21
-
Enhancement in the performance of nanostructured CuOa??ZnO solar cells by band alignment
摘要： In this study, we investigated the effect of cobalt doping on band alignment and the performance of nanostructured ZnO/CuO heterojunction solar cells. ZnO nanorods and CuO nanostructures were fabricated by a low-temperature and cost-effective chemical bath deposition technique. The band offsets between Zn1?xCoxO (x = 0, 0.05, 0.10, 0.15, and 0.20) and CuO nanostructures were estimated using X-ray photoelectron spectroscopy and it was observed that the reduction of the conduction band offset with CuO. This also results in an enhancement in the open-circuit voltage. It was demonstrated that an optimal amount of cobalt doping could effectively passivate the ZnO related defects, resulting in a suitable conduction band offset, suppressing interface recombination, and enhancing conductivity and mobility. The capacitance–voltage analysis demonstrated the effectiveness of cobalt doping on enhancing the depletion width and built-in potential. Through impedance spectroscopy analysis, it was shown that recombination resistance increased up to 10% cobalt doping, thus decreased charge recombination at the interface. Further, it was demonstrated that the insertion of a thin layer of molybdenum oxide (MoO3) between the active layer (CuO) and the gold electrode hinders the formation of a Schottky junction and improved charge extraction at the interface. The ZnO/CuO solar cells with 10% cobalt doped ZnO and 20 nm thick MoO3 buffer layer achieved the best power conversion efficiency of 2.11%. Our results demonstrate the crucial role of the band alignment on the performance of the ZnO/CuO heterojunction solar cells and could pave the way for further progress on improving conversion efficiency in oxide-based heterojunction solar cells.
关键词： nanostructured,solar cells,X-ray photoelectron spectroscopy,power conversion efficiency,molybdenum oxide,chemical bath deposition,band alignment,CuO–ZnO,cobalt doping
更新于2025-09-23 15:21:01
-
Deep insights into interface engineering by buffer layer for efficient perovskite solar cells: a first-principles study; é?????é??é??????¤aé?3è????μ?±???-?????2?±????é?￠?·￥?¨?????·±??￥???è§￡: ????????§????????????;
摘要： Recent years have seen swift increase in the power conversion efficiency of perovskite solar cells (PSCs). Interface engineering is a promising route for further improving the performance of PSCs. Here we perform first-principles calculations to explore the effect of four candidate buffer materials (MACl, MAI, PbCl2 and PbI2) on the electronic structures of the interface between MAPbI3 absorber and TiO2. We find that MAX (X = Cl, I) as buffer layers will introduce a high electron barrier and enhance the electron-hole recombination. Additionally, MAX does not passivate the surface states well. The conduction band minimum of PbI2 is much lower than that of MAPbI3 absorber, which significantly limits the band bending of the absorber and open-circuit voltage of solar cells. On the other side, suitable bandedge energy level positions, small lattice mismatch with TiO2 surfaces, and excellent surface passivation make PbCl2 a promising buffer material for absorber/electron-transport-layer interface engineering in PSCs. Our results in this work thus provide deep understanding on the effects of interface engineering with a buffer layer, which shall be useful for improving the performance of PSCs and related optoelectronics.
关键词： perovskite solar cells,band alignment,interfacial defect passivation,buffer layer,interface engineering
更新于2025-09-23 15:21:01
-
Decreasing Energy Loss and Optimizing Band Alignment for High Performance CsPbI3 Solar Cells through Guanidine Hydrobromide Post-Treatment
摘要： On account of the superior thermal stability and applicable band gap (~ 1.7 eV), the inorganic halide CsPbI3 perovskite solar cells (PSCs) have aroused intense interest in recent years. Nevertheless, the CsPbI3 PSCs are still facing a problem of high energy loss (Eloss) which leads to low open-circuit voltage (VOC). Herein, we developed efficient CsPbI3 PSCs through guanidine hydrobromide (GABr) post-treatment on the surface of CsPbI3 film. After optimizing, a supreme power conversion-efficiency (PCE) of 18.02% was obtained, which was higher than the original one (16.58%). By further studying, the characterization of passivation was found, which led to the reduced nonradiative recombination rate. Besides, the band alignment between CsPbI3 and interface layer is also optimized, leading to the decreased electron transport barrier for electron collection, and superb hole contact for furnishing a driving force in the hole transferring and forbidding electron to flow in the opposite direction.
关键词： energy loss,GABr,nonradiative recombination,CsPbI3,band alignment
更新于2025-09-23 15:21:01
-
Highly Efficient and Stable Pure 2D Perovskite Based Solar Cells with 3-Aminopropionitrile Organic Cation
摘要： Pure two-dimensional (2D) perovskite (n = 1) based perovskite solar cells (PSCs) have been proven to have excellent stability against humidity, but the photovoltaic performance is very poor due to the parallel orientation to the substrate and mismatched energy alignment in the PSC device. We report herein a novel bulky organic cation of 3-aminopropionitrile (3-APN) for constructing a pure 2D hybrid lead-iodide perovskite. The crystal structure of (3-APN)2PbI4 features a stable layered and undistorted PbI6 octahedral geometry ( ∠ Pb–I–Pb = 180o) with a small I···I distance (4.66 ?), and the crystals grow in a dominant out-of-plane direction to the substrate. In addition, the existence of intramolecular H-bond between cyano groups and ammonium heads result in an appropriate valence band level of (3-APN)2PbI4 for well-matched energy level alignment in the device, benefitting the interfacial charge transfer and hence better photovoltaic performance. As a result, the PSC with the pure 2D (3-APN)2PbI4 perovskite based PSC achieves power conversion efficiency of 3.39%, which is the highest value thus far for the pure 2D lead?iodide perovskite family, to the best of our knowledge. More importantly, this pure 2D (3-APN)2PbI4 perovskite based PSC demonstrates excellent stability against humidity. This work demonstrates that there is great potential to realize efficient and stable pure 2D perovskite based PSCs through the wise design of organic cations.
关键词： crystal orientation,3-aminopropionitrile,pure 2D,energy level alignment,perovskite solar cells
更新于2025-09-23 15:21:01
-
Mechanisms of LiF Interlayer Enhancements of Perovskite Light-Emitting Diodes
摘要： The use of LiF as a thin interlayer between the electron transport layer and cathode has played a pivotal role in remarkable advances in perovskite LEDs (PeLEDs); however, the mechanism behind the effect of LiF remains to be fully understood. Here we report a combined experimental and computational study from which we ascribe the benefits of a LiF interlayer to the migration of dissociated Li into the cathode and dissociated F into the anode. Electronic device simulations reveal that the former improves electron injection by lowering the Schottky barrier height, while the latter reduces the barrier width. These reduce turn-on voltage and improve current density and charge balance in LEDs. We fabricate PeLEDs with and without the LiF interlayer and link these materials and electronic phenomena to the device light-current-voltage characteristics. X-ray photoelectron spectroscopy obtained in sputter profiling of PeLEDs corroborates the dissociation of LiF.
关键词： LEDs,interface dipoles,metal-halide perovskites,photoelectron spectroscopy,band alignment
更新于2025-09-23 15:21:01
-
Critical role of interface contact modulation in realizing low-temperature fabrication of efficient and stable CsPbIBr2 perovskite solar cells
摘要： CsPbIBr2 perovskite solar cells (PSCs) have received considerable concern due to their excellent stability. However, the interface defects and imperfect band alignment between electron transporting layer (ETL) and perovskite is one of the main reasons for hindering further efficiency improvement. Herein, we modulate the band alignment and perovskite crystallization of the ETL/perovskite interface by employing ZnO and SnO2 as ETL, which exhibit high electron mobility and can be fabricated at low temperature. Both ZnO and SnO2-based devices were fabricated at low temperature below 160 ℃. First, the effect of ZnO and SnO2 on the performance of CsPbIBr2 PSCs is systematically investigated. SnO2-based PSCs show a higher power conversion efficiency (PCE) of 10.81% as a consequence of improved Voc and fill factor (FF) as compared to 9.70% of ZnO counterpart, which is attributed to improved band alignment and perovskite crystallization, leading to enhanced electron extraction, reduced interface nonradiative recombination and improved carrier lifetimes. Remarkably, SnO2 ETL can also reduce hysteresis and improve device stability as compared to ZnO ETL. The present study unveils the critical role of interface contact modulation of CsPbIBr2 PSCs and provides an insightful strategy for preparing efficient and stable low-temperature inorganic PSCs.
关键词： Interface contact modulation,Perovskite solar cells,Band alignment,CsPbIBr2
更新于2025-09-23 15:21:01
-
[SpringerBriefs in Applied Sciences and Technology] Air-Stable Inverted Organic Light-Emitting Diodes || Carrier Injection Mechanism
摘要： Both hole and electron injection layers are commonly used in recent OLEDs to reduce the injection barrier between electrodes and organic layers. This injection barrier originates from the energy difference between the work function (WF) of the electrode and the energy level of the organic layer. For instance, the hole injection barrier is defined as the energy difference between the Fermi level of the anode and the highest occupied molecular orbital (HOMO) level of the organic layer on the anode, as shown in Fig. 4.1a. Thus, an ideal hole injection material is the material that can make the surface WF of the anode larger (Fig. 4.1b). On the other hand, an ideal electron injection material is the material that can make the surface WF of the cathode smaller (Fig. 4.1c).
关键词： energy level alignment,OLEDs,electron injection,hole injection,work function
更新于2025-09-23 15:21:01
-
Highly Efficient Inorganic-Organic Heterojunction Solar Cells Based on Polymer and CdX (X=Se, Te) Quantum Dots: An Insight from a Theoretical Study
摘要： By using the density functional method, we explore the potentiality of recently synthesized CdX (X=Se, Te)QD/P3HT composites in solar energy conversion devices. Our study reveals that inorganic/organic hybrid CdXQD/P3HT nanocomposites with larger size of CdX QDs exhibit type-II band alignment, suggesting efficient charge separation upon photoexcitation. But for smaller size of QDs, the composites show type-I band alignment which are devoid of charge separation and thus are not suitable for solar cell applications. To remove this obstacle, we focus on chemical modification to polymer P3HT. The substitution of hydrogen at the beta position of each thiophene ring of polymer by electron withdrawing group (CN) results type-II band alignment and yield spatial charge separation even for smaller size of QDs. Finally, we calculated the powerconversion efficiency (PCE) of CdXQD and CN functionalized P3HT nanocomposites. The maximum calculated PCE value of 10.82% is achieved, which makes them immensely competitive with other reported heterojunction solar cells.
关键词： CdX (X=Se, Te)QD/P3HT composites,powerconversion efficiency,solar energy conversion,charge separation,type-II band alignment
更新于2025-09-23 15:21:01
-
[Lecture Notes in Computer Science] Pattern Recognition and Computer Vision Volume 11256 (First Chinese Conference, PRCV 2018, Guangzhou, China, November 23-26, 2018, Proceedings, Part I) || Image Stitching Using Smoothly Planar Homography
摘要： It is an important but challenging issue to construct a reasonable seamless image mosaic from images with non-ignorable di?erent viewpoints or multiple distinct planes. The main limitations of existing image-stitching approaches lie in two facts: (a) the multiple plane nature of scenes has not been well considered in the image alignment step, which usually results in obvious misalignments; (b) the ignored alignment errors often lead to broken structures in the seam composition step. To overcome these problems, this paper proposed a smoothly planar homography model for image stitching, by considering the multi-plane geometry of natural scene. First, we integrate local warps estimated in each plane to achieve smoothly plane stitching. Then, we introduce a novel alignment-guided seam composition to handle parallax. Experimental results on a series of challenging data demonstrate that our model achieves the state-of-the-art stitching performance.
关键词： Image alignment,Image stitching,Homography
更新于2025-09-23 15:21:01