- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Numerical modelling of non-fullerene organic solar cell with high dielectric constant ITIC-OE acceptor
摘要： The low dielectric constant of organic semiconductors has been a limiting factor in the organic photovoltaics. Non-Fullerene Acceptor Bulk Heterojunction (NFA-BHJ) organic solar cells with high dielectric constant acceptors have been gaining a lot of attention. No simulation work has been done on NFA-BHJ organic solar cell with a high dielectric constant acceptor so far to study the influence of various material parameters on the device performance. In this work, a comprehensive device modelling of the conventional structure of NFA-BHJ with poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b]dithiophene)-co-(1,3-di(5-thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c]dithiophene-4,8-dione)] (PBDB-T)as the polymer donor and (3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetraki(4-hexylphenyl)-dithieno [2,3-d:2,3-d]-s-indaceno [1,2-b:5,6-b]dithiophene)) with Oligo-Ethylene side chain (ITIC-OE) as the non-fullerene acceptor is performed. We did a detailed analysis on the impact of technological parameters on the cell performance and optimized the device characteristics to produce improved efficiency. Numerical simulation is done using SCAPS 1-D program and the validity of simulated output has been verified by comparing with the measurements from reported literature. Optimization of the device parameters produced an improved device performance with an open circuit voltage of 0.9562 V, short circuit current density of mA/cm2, Fill factor of 69.75 % and a power conversion efficiency of 11%. The results are encouraging to develop NFA-BHJ organic solar cells with high dielectric constant acceptors in the near future.
关键词： numerical modelling,Non-Fullerene Acceptor Bulk Heterojunction,high dielectric constant,ITIC-OE acceptor,organic solar cells
更新于2025-09-23 15:19:57
-
Local valence electronic states of silicon (sub)oxides on HfO2/Si-(sub)oxide/Si(110) and HfSi2/Si-(sub)oxide/Si(110) Islands
摘要： The effect on the local valence electronic states of Sin+ suboxide components (n = 2, 3, and 4) of hafnium deposited on a low-index Si(110) substrate is investigated by Si-L23VV Auger electron Sin+-2p photoelectron coincidence spectroscopy (Si-L23VV-Sin+-2p APECS), and the chemical states and stabilities are discussed. Hafnium-covered Si(110) is immediately oxidized to HfO2 and SiO2 because hafnium serves as an effective catalyst for Si oxidation. Therefore, a HfO2/Sin+-(sub)oxide/Si(110) [HfO2/Sin+/Si(110)] structure is easily formed (n = 1, 2, 3, and 4). Oxygen diffusion from HfO2 layers toward the Si(110) substrate is promoted by annealing at 923 K. Oxygen atom desorption from the HfO2/Sin+/Si(110) surface occurs after annealing at 1073 K, and HfSi2 islands (i-HfSi2) are formed with a partly exposed Si(110)-16 × 2 double domain (DD) surface. i-HfSi2 shows low reactivity toward O2 molecules, whereas the exposed Si(110)-16 × 2 DD surface is immediately oxidized. Here, a i-HfSi2/Sin+-(sub)oxide/Si(110) structure is formed. Furthermore, we measure the Si-L23VV-Sin+-2p APECS spectra of Sin+ in the HfO2/Sin+/Si(110) and the i-HfSi2/Sin+/Si(110) structures (n = 2, 3, and 4) to evaluate the local valence electronic states of the Sin+ (sub)oxide components. The binding energy at the valence band maximum (BEVBM) of Sin+ in the i-HfSi2/Sin+/Si(110) structure is lower than 1.5 ± 0.7 eV as compared to that in the HfO2/Sin+/Si(110) structure (n = 2, 3, and 4). The local valence electric states of the nearest neighbors and the second neighbors through oxygen of Sin+ are determined to affect those of the Sin+ atom (n = 2, 3, and 4). The Sin+ atoms in the i-HfSi2/Sin+/Si(110) structure can directly bond to hafnium atoms as the nearest neighbors and most commonly have Sim+ atoms in lower ionic valence states as second neighbors (m < 4), whereas the Sin+ atoms in the HfO2/Sin+/Si(110) structure cannot form this bond. In addition, the existence of Hf silicide and Si in lower ionic valence states can reduce the band gap of the HfO2/Si(110) structure.
关键词： High-dielectric-constant material,X-ray photoelectron spectroscopy,Local valence electronic states at surface and interface,Synchrotron radiation,Auger photoelectron coincidence spectroscopy,Metal-insulator-semiconductor structure
更新于2025-09-11 14:15:04
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Metrological Challenge for Scanning Microwave Microscopy
摘要： We have demonstrated a near-field scanning microscopy (NSOM) based on an atomic force microscope (AFM) for characterization of high dielectric constant materials. The NSOM is applied to measure the dielectric constant of high dielectric constant materials by using a near-field microwave microscope. The NSOM is based on a cantilever with a sharp tip that is used to scan the sample surface. The microwave signal is applied to the tip and the reflected signal is detected by a microwave detector. The dielectric constant of the sample is determined by the phase shift of the reflected signal. The NSOM can measure the dielectric constant of materials with high spatial resolution. The NSOM is used to measure the dielectric constant of high dielectric constant materials such as BaTiO3, SrTiO3, and Pb(Zr,Ti)O3. The dielectric constant of these materials is measured with high accuracy and high spatial resolution.
关键词： dielectric constant,high dielectric constant materials,microwave,AFM,NSOM
更新于2025-09-10 09:29:36
-
Structural, dielectric, and impedance study on ZnO doped Sr(Fe0.5Nb0.5)O3 ceramics
摘要： SrFe0.5Nb0.5O3 (SFN) ceramics doped with ZnO were synthesized via a conventional mixed oxide technique. Phase formation investigation by X-ray diffraction technique (XRD) revealed that all ceramic samples exhibited pure perovskite phase. Grain size as observed by an electron microscopy (SEM), was found to decrease with increasing the additive concentration. Dielectric properties and other related properties of the ceramics were also investigated. Very high dielectric constants > 3.3×105 (at temperature 250 °C and 1 kHz) were found for the 3 vol% doped samples. The impedance spectroscopy analysis suggested that the dielectric behavior of the samples could be linked with the Maxwell - Wagner polarization mechanism.
关键词： Perovskite,High dielectric constant,Ceramics,Maxwell - Wagner polarization,Impedance spectroscopy,SrFe0.5Nb0.5O3
更新于2025-09-04 15:30:14