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Influence of Passivation Layers on Positive Gate Bias-Stress Stability of Amorphous InGaZnO Thin-Film Transistors
摘要: Passivation (PV) layers could effectively improve the positive gate bias-stress (PGBS) stability of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs), whereas the related physical mechanism remains unclear. In this study, SiO2 or Al2O3 films with different thicknesses were used to passivate the a-IGZO TFTs, making the devices more stable during PGBS tests. With the increase in PV layer thickness, the PGBS stability of a-IGZO TFTs improved due to the stronger barrier effect of the PV layers. When the PV layer thickness was larger than the characteristic length, nearly no threshold voltage shift occurred, indicating that the ambient atmosphere effect rather than the charge trapping dominated the PGBS instability of a-IGZO TFTs in this study. The SiO2 PV layers showed a better improvement effect than the Al2O3 because the former had a smaller characteristic length (~5 nm) than that of the Al2O3 PV layers (~10 nm).
关键词: thin-film transistor (TFT),positive gate bias stress (PGBS),passivation layer,characteristic length,amorphous InGaZnO (a-IGZO)
更新于2025-09-23 15:21:21
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Vacuum-free, Room-temperature Organic Passivation of Silicon: towards Very Low Recombination of Micro/Nano-Textured Surface Structures
摘要: Crystalline silicon (c-Si) solar cells remain dominant in the photovoltaic (PV) market due to their cost-effective advantages. However, the requirement for expensive vacuum equipment and the power-hungry thermal budget for surface passivation technology, which is one of the key enablers of the high performance of c-Si solar cells, impede further reductions of costs. Thus, the omission of the vacuum and high-temperature process without compromising the passivation effect is highly desirable due to cost concerns. Here, we demonstrate a vacuum-free, room-temperature organic Nafion thin-film passivation scheme with an effective minority carrier lifetime (τeff) exceeding 9 ms on an n-type c-Si wafer with a resistivity of 1-5 Ω·cm, corresponding to an implied open circuit voltage (iVoc) of 724 mV and upper-limit surface recombination velocities (SRV) of 1.46 cm/s, which is a level that is in line with the hydrogenated amorphous Si film-passivation scheme used in the current PV industry. We find that the Nafion film passivation of Si can be enhanced in an O2 atmosphere and that the Nafion/c-Si interface oxidation should be responsible for the passivation mechanism. This highly effective passivation is also achieved on various micro/nano-textured Si surface structures from actual production, including a pyramidal surface and nanopore-pyramid hybrid structure with nanopores on the inclined plane of the pyramid. We develop an organic Nafion-passivated n-type back-junction Si solar cell to examine application in a real device. The open circuit voltage (Voc) of the solar cell with the Nafion passivation layer achieves a clear improvement (30.8 mV) over those without the passivation layer, resulting in an increase (1.5%) in the power conversion efficiency (PCE). These results suggest the potential use of these organic electronics with current Si microelectronics and a new strategy for the development of vacuum-free, low-temperature Si-based PVs at low cost.
关键词: passivation,Silicon,Nafion thin film,Photovoltaic
更新于2025-09-23 15:21:21
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Investigation of hydrogen effect on phosphorus-doped polysilicon thin films
摘要: Polycrystalline silicon is widely used in microelectronic and photovoltaic applications. The main problem of this material is the recombination of charge carriers at the grain boundaries which affects the efficiency of the polycrystalline silicon solar cells. In order to improve the crystalline quality and the electrical properties of phosphorus-doped poly-silicon thin films, heat treatments under hydrogen were carried out. This allowed the occupation of the dangling bonds at the grain boundaries and made them inactive, which resulted in improved optoelectronic properties of the treated samples. It has been shown that the effect of hydrogen on the electrical characteristics is more pronounced for low doping concentrations where a 20% improvement of the free carrier concentration was obtained. In addition, the results have shown that the introduction of hydrogen in poly-silicon thin films reduces the density of trap states at the grain boundaries.
关键词: hydrogen,passivation,solar cells,grain boundaries,Polycrystalline silicon
更新于2025-09-23 15:21:21
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Trap State and Charge Recombination in Nanocrystalline Passivized Conductive and Photoelectrode Interface of Dye-Sensitized Solar Cell
摘要: The dynamic competition between electron generation and recombination was found to be a bottleneck restricting the development of high-performance dye-sensitized solar cells (DSSCs). Introducing a passivation layer on the surface of the TiO2 photoelectrode material plays a crucial role in separating the charge by preventing the recombination of photogenerated electrons with the oxidized species. This study aims to understand in detail the kinetics of the electron recombination process of a DSSC fabricated with a conductive substrate and photoelectrode film, both passivized with a layer of nanocrystalline TiO2. Interestingly, the coating, which acted as a passivation layer, suppressed the back-electron transfer and improved the overall performance of the integrated DSSC. The passivation layer reduced the exposed site of the fluorine-doped tin oxide (FTO)–electrolyte interface, thereby reducing the dark current phenomenon. In addition, the presence of the passivation layer reduced the rate of electron recombination related to the surface state recombination, as well as the trapping/de-trapping phenomenon. The photovoltaic properties of the nanocrystalline-coated DSSC, such as short-circuit current, open-circuit voltage, and fill factor, showed significant improvement compared to the un-coated photoelectrode film. The overall performance efficiency improved by about 22% compared to the un-coated photoelectrode-based DSSC.
关键词: Electron recombination,electrochemical analysis,nanocrystalline coating,Dye-sensitized solar cell,passivation layer
更新于2025-09-23 15:21:01
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The effect of ethylene-amine ligands enhancing performance and stability of perovskite solar cells
摘要: The inclusion of long chain alkyl-amine organics in perovskite solar cells (PSCs) has been reported to enhance water-resistance of perovskite films, but this strategy lowers device efficiency at the same time. Herein, we develop an approach that combines molecular dimensionality control and interfacial passivation of perovskite layers using a novel post-device treatment (PDT) with the vapour of ethylene-amine salts of different carbon chain lengths to improve both efficiency and stability of the PSCs. The effect of a series of ligand vapours including ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA) was systematically investigated. A thin hydrophobic two-dimensional (2D) perovskite capping layer formed in the device after the 3D perovskite was exposed to the vapour of long chain ethylene-amine molecules, such as DETA and TETA, which protected the underlying bulk 3D perovskite layer from moisture attack. An improved energy level alignment was obtained in the treated devices and that a reduced density of defects was present in the perovskite after treatment with DETA and TETA vapours. Consequently, enhanced efficiency from 17.07% to 18.09% (DETA) and improved moisture stability with PCE retention from 73.8% to 90.0% (TETA) under a relative humidity>65% for 1000 h were achieved by this vapour treatment respectively.
关键词: Dimensional engineering,Moisture stability,Perovskite solar cells,Surface passivation
更新于2025-09-23 15:21:01
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Conductive Holea??Selective Passivating Contacts for Crystalline Silicon Solar Cells
摘要: Defect state passivation and conductivity of materials are always in opposition; thus, it is unlikely for one material to possess both excellent carrier transport and defect state passivation simultaneously. As a result, the use of partial passivation and local contact strategies are required for silicon solar cells, which leads to fabrication processes with technical complexities. Thus, one material that possesses both a good passivation and conductivity is highly desirable in silicon photovoltaic (PV) cells. In this work, a passivation-conductivity phase-like diagram is presented and a conductive-passivating-carrier-selective contact is achieved using PEDOT:Nafion composite thin films. A power conversion efficiency of 18.8% is reported for an industrial multicrystalline silicon solar cell with a back PEDOT:Nafion contact, demonstrating a solution-processed organic passivating contact concept. This concept has the potential advantages of omitting the use of conventional dielectric passivation materials deposited by costly high-vacuum equipment, energy-intensive high-temperature processes, and complex laser opening steps. This work also contributes an effective back-surface field scheme and a new hole-selective contact for p-type and n-type silicon solar cells, respectively, both for research purposes and as a low-cost surface engineering strategy for future Si-based PV technologies.
关键词: solar cells,PEDOT,Nafion,passivation,conductivity
更新于2025-09-23 15:21:01
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Efficiency Enhancement of Cu(In,Ga)(S,Se)2 Solar Cells by Indium-doped CdS Buffer Layer
摘要: Improving power conversion efficiency of photovoltaic devices has been widely investigated, however, most of researches mainly focus on the modification of the absorber layer. Here, we present an approach to enhance the efficiency of Cu(In,Ga)(S,Se)2 (CIGSSe) thin-film solar cells simply by tuning the CdS buffer layer. The CdS buffer layer was deposited by chemical bath deposition. Indium doping was done during the growth process by adding InCl3 into the growing aqueous solution. We show that the solar cell efficiency is increased by properly Indium doping. Based on the characteristics of the single CdS (with or without In-doping) layer and of the CIGSSe/CdS interface, we conclude that the efficiency enhancement is attributed to the interface-defect passivation of heterojunction, which significantly improves both open circuit voltage and fill factor. The results were supported by SCAPS simulations, which suggest that our approach can also be applied to other buffer systems.
关键词: CdS buffer layer,interface passivation,SCAPS simulations,Indium doping,CIGSSe-based solar cell
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The Influence of Al <sub/>2</sub> O <sub/>3</sub> Passivation of III-V on Ge Multijunction Solar Cells to the Spatial Distribution of Luminescent Coupling Effect
摘要: The nonuniformity of luminescent coupling (LC) effect in III-V based multijunction solar cells (MJSCs) is partly ascribed to recombination at perimeter defects. An attempt to solve this was done by sidewall passivation of InGaP/GaAs/Ge triple junction solar cells through atomic layer deposition of thin Al2O3. Results revealed that sidewall passivation of a complete MJSC can increase LC current collection in a limiting GaAs middle cell by 21.9% and enhance its uniformity by 7.2%; hence, demonstrating a non-invasive way to improve current matching among subcells.
关键词: photovoltaic cells,luminescence coupling,current mapping,atomic layer deposition,laser beam-induced passivation
更新于2025-09-23 15:21:01
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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
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Suppressing Shallow Defect of Printable Mesoscopic Perovskite Solar Cells with a N719@TiO <sub/>2</sub> Inorganic-Organic Core-Shell Structured Additive
摘要: Shallow defects are one of the energy states that trap photoexcited electrons leading to charge recombination and limit the increase in the photocurrent of perovskite solar cells (PSCs). Due to the large perovskite thickness and uncontrollable crystallization processes, suppressing shallow defects, especially methylamine (MA) vacancies, has become a key challenge for fully printable PSCs. Herein, nano-TiO2 is unprecedentedly used to load the commercial dye N719, forming N719@TiO2 nanoparticles, which crucially improves the passivation effect of MA vacancies on the surface of perovskite and charge extraction, by the unbounded carboxyl group of N719 as a shell on the surface of TiO2. Meanwhile, the core TiO2 serves as a centre to bind the dyes, assisting the perovskite crystallization and enhancing the passivation effect. It is found that the charge extraction increases to 1.8007 (cid:1) 10 N719@TiO2 from 1.5507 (cid:1) 10 short-circuit current density (Jsc) is signi?cantly enhanced to 23.58 mA cm in the device containing N719@TiO2 over that of the control device (21.95 mA cm PSCs via organic passivator with carboxyl anchoring group loaded on n-type semiconductors (nano-TiO2).
关键词: passivation,printable solar cells,dyes,titanium dioxide,perovskite solar cells
更新于2025-09-23 15:21:01