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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - A Simulation Perspective: The Potential and Limitation of Ge GAA CMOS Devices
摘要： The electrical characteristics of <110> n/p Ge nanowire transistors (NWTs) with the cross section of 6×6nm2 have been studied. The ION performance and the subthreshold swing are simulated by multi-subband Boltzmann transport equation and ballistic quantum transport solvers, respectively. The performance of <110> nGe NWTs is sensitive to the barrier height of interfacial layer due to highly-anisotropic Λ-valleys. The dimension-dependent k·p parameters based on tight-binding full band are used to address the strong confinement of pGe NWTs. Comparing to Si NWTs, the intrinsic ION is twice as high for both n/p Ge NWTs at 28nm channel length. As the channel length is scaled down, such ION benefit is maintained till the tunneling effect comes in and degrades the subthreshold swing.
关键词： source-to-drain tunneling,Ge,ballistic ratio,nanowire,CMOSFETs,interfacial layer
更新于2025-09-23 15:22:29
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Interfacing green synthesized flake like-ZnO onto TiO <sub/>2</sub> as a bilayer electron extraction for efficient perovskite solar cells
摘要： To improve the performance of the PSCs, it is essential to prevent the carrier recombination losses at the interfaces of the transparent metal oxide electrode/electron transport layer (ETL) / active absorber perovskite layer. This present work reports about the green synthesis approach used for the preparation of flake like-ZnO nanostructure (GF-ZnO NSs), naturally extracted from the leaf of Albizia Amara - as a reducing cum capping agent. Herein, we have introduced the above prepared an n-type GF-ZnO NSs material as efficient electron transport interfacial layer (bi-ETL) at the ETL/perovskite junction in the fabricated perovskite solar cells (PSCs). The structure of the fabricated PSC device as follow: Glass/ITO/bi-ETL (c-TiO2/GF-ZnO NSs)/CH3NH3PbI3-xClx/Spiro-MeOTAD/Au. A comparative study has also been made by deploying electron transport materials such as c-TiO2 and GF-ZnO NSs separately. From this, it has been found that the bi-ETL perovskite solar cell devices achieved a maximum power conversion efficiency (PCE) of 7.83% with open-circuit voltage (VOC) of 0.728 V, short circuit current density (JSC) of 20.46 mA/cm2 and a fill factor (FF) of 52.61% compared to that of the chemically reduced ZnO based devices. Whereas, the c-TiO2, GF-ZnO NSs and the chemically reduced CR-ZnO based ETL based devices achieved a PCE of 4.84%, 5.82% and 6.81% respectively. The obtained better performance of the bi-ETL based devices is ascribed to the enhanced carrier extraction and the reduced recombination losses at the interface between the ETL and the active perovskite layer.
关键词： bilayer electron extraction,green synthesis,Perovskite solar cells,Interfacial layer,ZnO nanostructure,Albizia Amara leaf extract
更新于2025-09-23 15:19:57
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Polyolefin Elastomer as the Anode Interfacial Layer for Improved Mechanical and Air Stabilities in Non-fullerene Solar Cells
摘要： Despite the breakthroughs in power conversion efficiency (PCE) values of organic solar cells (OSCs), the other important issue concerns stability, which is urgently needed to be resolved for potential commercialization. A commercial and chemically stable polyolefin elastomer (POE) was incorporated into high-performance PBDB-T:ITIC, PM6:IT-4F and PM6:Y6 non-fullerene systems to serve as the anode interfacial layer, affording remarkably improved mechanical and air stabilities when compared with those of the most studied MoO3 interfacial layer. The POE was found to selectively transport holes rather than electrons, due to the upshifted surface contact potential of active layer and the better ohmic contact between active layer and electrode. The POE serving as an encapsulating layer is supposed to suppress the penetration of water and oxygen in addition to the diffusion of Ag atoms into active layer. After storing in an air environment with a humidity of approximately 70% for 150 days, the PCE of the device based on PM6:IT-4F with the POE anode interfacial layer decreased from 11.88% to 9.60%, retaining 80.8% of its original PCE value. The device using MoO3 as the anode interfacial layer showed a PCE value that was sharply reduced from 12.31% to 2.98% after storing for only 30 days. The POE could be potentially useful for flexible and large-scale device fabrication, accelerating the commercialization of OSCs.
关键词： stability,polyolefin elastomer,non-fullerene,organic solar cells,interfacial layer
更新于2025-09-19 17:13:59
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Defect Passivation by Amide-Based Hole Transporting Interfacial Layer Enhanced Perovskite Grain Growth for Efficient p-i-n Perovskite Solar Cells
摘要： In this study we synthesized four A-D-A type hole transporting materials (HTMs) of SY1~SY4 for an HTMs/interfacial layer with carbazole as the core moiety and ester/amide as the acceptor unit. These HTMs contain 4-hexyloxyphenyl substituents on the carbazole N atom, with extended π-conjugation achieved through phenylene and thiophene units at the 3,6-positions of the carbazole. When using amide-based HTMs SY2 as a dopant-free HTM in a p–i–n perovskite solar cell (PSC), we achieved a power conversion efficiency (PCE) of 13.59% under AM 1.5G conditions (100 mW cm–2); this PCE was comparable with that obtained when using PEDOT:PSS as the HTM (12.33%). Amide-based SY2 and SY4 HTMs showed a larger perovskite grain than SY1 and SY3, due to the passivation of traps/defects at the grain boundaries and stronger interaction with the perovskite layer. In further investigation, we demonstrated highly efficient and stable PSCs when using the dopant-free p–i–n device structure ITO/NiOx/interfacial layer (SY-HTMs)/perovskite/PC61BM/BCP/Ag. The interfacial layer improved the PCEs and large grain size (micrometer scale) of the perovskite layer due to defect passivation and interface modification; the amide group exhibited a Lewis base adduct property coordinated to Ni and Pb ions in the NiOx and perovskite, bifacial defect passivation and reduced the grain boundaries to improve the crystallinity of the perovskite. The amide-based SY2 exhibited the stronger interaction with the perovskite layer than that of ester-based SY1, which is related to the observations in X-ray absorption near edge structure (XANES). The best performance of the NiOx/SY2 device was characterized by a short-circuit current density (Jsc) of 21.76 mA cm–2, an open-circuit voltage (Voc) of 1.102 V, and a fill factor (FF) of 79.1%, corresponding to an overall PCE of 18.96%. The stability test of the PCE of the NiOx/SY2 PSC device PCE showed a decay of only 5.01% after 168 h; it retained 92.01% of its original PCE after 1000 h in Ar atmosphere. Time-resolved photoluminescence (TRPL) spectra of the perovskite films suggested that the hole extraction capabilities of the NiOx/SY-HTMs were better than that of the bare NiOx. The superior film morphologies of the NiOx/SY-HTMs were responsible for the performances of their devices being comparable with those of bare NiOx-based PSCs. The photophysical properties of the HTMs were analyzed through time-dependent density functional theory with the B3LYP functional.
关键词： p-i-n type perovskite solar cells,interfacial layer,amide-based hole transporting material,perovskite solar cells
更新于2025-09-16 10:30:52
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Adjusting Interfacial Chemistry and Electronic Properties of Photovoltaics Based on a Highly Pure Sb <sub/>2</sub> S <sub/>3</sub> Absorber by Atomic Layer Deposition
摘要： The combination of oxide and heavier chalcogenide layers in thin film photovoltaics suffers limitations associated with oxygen incorporation and sulfur deficiency in the chalcogenide layer or with a chemical incompatibility which results in dewetting issues and defect states at the interface. Here, we establish atomic layer deposition (ALD) as a tool to overcome these limitations. ALD allows one to obtain highly pure Sb2S3 light absorber layers, and we exploit this technique to generate an additional interfacial layer consisting of 1.5 nm ZnS. This ultrathin layer simultaneously resolves dewetting and passivates defect states at the interface. We demonstrate via transient absorption spectroscopy that interfacial electron recombination is one order of magnitude slower at the ZnS-engineered interface than hole recombination at the Sb2S3/P3HT interface. The comparison of solar cells with and without oxide incorporation in Sb2S3, with and without the ultrathin ZnS interlayer, and with systematically varied Sb2S3 thickness provides a complete picture of the physical processes at work in the devices.
关键词： interfacial layer,extremely thin absorber,transient absorption,atomic layer deposition,antimony sulfide,ultrathin layer
更新于2025-09-12 10:27:22
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Enhancing the Power Conversion Efficiency of Organic Solar Cells
摘要： Organic solar cells (OSCs) have significantly reduced the overall cost of solar energy system, making solar oriented devices universally clean and green energy source. However, to make OSCs more competitive in diverse photovoltaic (PV) technologies, it is essential to attain high efficiencies by analyzing novel materials and realizing optimal arrangements of donor–acceptor materials. In this paper, we attempt to show a terse depth insight of OSCs by investigating three novel architecture schemes with special emphasis on improving the power conversion efficiency. The materials include include i) poly (3-hexylthiophene):[(6,6)]-phenyl C61 butyric acid methyl ester (P3HT:PCBM), ii) thieno [3,4-b] thiophene-alt-benzodithiophene:[6,6]-phenyl-C61 butyric acid methyl ester (PTB7:PCBM), and iii) poly{4,4′-bis(2-ethylhexyl) dithieno [3,2-b:2′,3′-d] silole-alt-5,6-difluoro-4,7-bis (4-hexylthiophen-2-yl)-2,1,3-benzothiadiazle):[6,6]-phenyl-C61 butyric acid methyl ester (PDTS-DTffBT:PCBM), respectively. Results show that the extracted performance parameters including short circuit current (JSC) = 10.88 mA/m2, open circuit voltage (Voc) = 0.82 V, fill factor (FF) = 83.52%, and efficiency (?) = 7.49% is highest for the second scheme among others. Different intermediate layers have also been analyzed with the objective to reduce the recombination losses and enhance the power conversion efficiency of the proposed cell. The impact of temperature on the overall ? is also presented and it is discovered that high temperature reduces the performance of the solar cell. Furthermore, the performance of the proposed structure is compared with various kinds of OSCs and it is found that our design exhibit highest efficiency. The achievement of high efficiencies in this work may accelerate the practical applications of OSCs.
关键词： interfacial layer,absorber materials,Organic solar cell,and efficiency.
更新于2025-09-12 10:27:22
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New Antimony-Based Organic–Inorganic Hybrid Material as Electron Extraction Layer for Efficient and Stable Polymer Solar Cells
摘要： Hybrid organic-inorganic materials are a new class of material used as interfacial layers in polymer solar cells. A hybrid material, composed of antimony as inorganic part and diaminopyridine as organic part, is synthesized and described as a new material for electron extraction layer in polymer solar cells and compared to the recently demonstrated hybrid materials using bismuth instead of antimony. The hybrid compound is solution-processed onto the photoactive layer based on a classical blend, composed of PTB7-Th low bandgap polymer as donor mixed with PC70BM fullerene as acceptor material. By using a regular device structure and an aluminum cathode, the solar cells exhibited a power conversion efficiency of 8.42%, equivalent to the reference device using ZnO nanocrystals as interfacial layer, and strongly improved compared to bismuth-based hybrid material. The processing of extraction layers up to a thickness of 80 nm of such hybrid material reveals that the change from bismuth to antimony has strongly improved the charge extraction and transport properties of the hybrid materials. Interestingly, nanocomposites made of the hybrid material mixed with ZnO nanocrystals in a 1:1 ratio further improved the electronic properties of the extraction layers, leading to power conversion efficiency of 9.74%. This was addressed to a more closely packed morphology of the hybrid layer, leading to further improved electron extraction. It is important to note that these hybrid electron extraction layers, both pure and ZnO-doped, also greatly improved the stability of solar cells, both under dark storage in air and under lighting under inert atmosphere compared to solar cells treated with ZnO intermediate layers.
关键词： solar cell,morphology,hybrid material,electron extraction,nanocrystals,interfacial layer
更新于2025-09-12 10:27:22
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Toward Highly Thermal Stable Perovskite Solar Cells by Rational Design of Interfacial Layer
摘要： Heat is crucial to the long term stability of perovskite solar cells (PVSCs). Herein, thermal stability of PVSCs based on metal oxide (MO) and polymer (P) was investigated. Firstly, chemical decomposition behavior of perovskite films was characterized and analyzed, revealing that chemically active MO would accelerate the decomposition of methylamine lead iodide (MAPbI3). Secondly, thermal-induced stress, resulting from the mismatched thermal expansion coefficients of different layers of PVSCs, and its effect on the mechanical stability of perovskite films were studied. Combining experiment and simulation, we conclude that “soft” (low modulus) and thick (> 20 nm) interfacial layers offer better relaxation of thermal-induced stress. As a result, PVSCs employing thick polymer interfacial layer offer a remarkably improved thermal stability. This work offers not only the degradation insight of perovskite films on different substrates, but also the path toward highly thermal stable PVSCs by rational design of interfacial layers.
关键词： perovskite solar cells,mechanics simulation,interfacial layer,heat endurance,kinetics analysis
更新于2025-09-12 10:27:22
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A zwitterionic polymer as an interfacial layer for efficient and stable perovskite solar cells
摘要： Perovskite solar cells have been rapidly developed in the past ten years. It was demonstrated that the interfacial layer plays an important role in device performance of perovskite solar cells. In this study, we report utilization of a photoinitiation-crosslinked zwitterionic polymer, namely dextran with carboxybetaine modified by methacrylate (Dex-CB-MA), as an interfacial layer to improve the film morphology of the CH3NH3PbI3 photoactive layer and the interfacial contact between the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole extraction layer and CH3NH3PbI3 photoactive layer. It is found that the Dex-CB-MA thin layer forms a better band alignment between the PEDOT:PSS hole extraction layer and CH3NH3PbI3 photoactive layer, and improves the crystallization of the CH3NH3PbI3 photoactive layer, resulting in efficient charge carrier transport. As a result, perovskite solar cells with the PEDOT:PSS/Dex-CB-MA hole extraction layer exhibit more than 30% enhancement in efficiency and dramatically boosted stability as compared with that with the PEDOT:PSS hole extraction layer. Our studies provide an effective and facile way to fabricate stable perovskite solar cells with high power conversion efficiency.
关键词： interfacial layer,zwitterionic polymer,stability,perovskite solar cells,power conversion efficiency
更新于2025-09-12 10:27:22