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Synergistic Effects of Charge Transport Engineering and Passivation Enabling Efficient Inverted Perovskite Quantum-dot Light-emitting Diodes
摘要： All inorganic perovskite quantum dots (QDs) have attracted much attention in the optoelectronic devices due to their fascinating properties such as high photoluminescence quantum yields (PLQYs), narrow emission peak, and facile synthesis process. Herein, we report a synergistic strategy of interfacial engineering and passivation. We construct an inverted device structure with Zinc Magnesium Oxide (Zn0.95Mg0.05O) as electron transport layer and p-n charge generation junction of (N,N’-Bis(naphthalen-1-yl)- N,N’- bis(phenyl) benzidine/ 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile) as hole transport layer to facilitate and balance the charge injection/transport. Meanwhile, a facile post-passivation technique is employed to passivate the cesium lead bromide (CsPbBr3) QDs via supplement of Br anion. The treated QDs exhibit improve PLQY due to decreased surface defect sites and enhanced radiative recombination. As a result, our perovskite quantum dot light-emitting diodes (PVQDLEDs) obtain a maximum luminance of 75792 cd m-2, an extremely low turn-on voltage of 1.9 V, and a maximum external quantum efficiency (EQE) of 5.95%, leading to an increase in EQE by 100% compared with that of the control device. Our work offers an effective approach to improve the performance of PVQDLEDs via multiple effects for the application of displays and solid-state lighting.
关键词： perovskite quantum dots,inverted device structure,passivation,light-emitting diodes,charge transport engineering
更新于2025-09-19 17:13:59
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Impact of 1,2-ethanedithiol treatment on luminescence and charge-transport characteristics in colloidal quantum-dot LEDs
摘要： We report on a substantial increase in luminance and luminous ef?ciency of green-light emitting devices (LEDs) that use colloidal CdSe@ZnS quantum dots (QDs) as a light-emitting material in response to treatment with 1,2-ethanedithiol (EDT). The maximum luminance increased from 1146 to 8075 cd m?2, and luminous yield from 0.15 to 1.41 cd A?1 as a result of treating an incomplete device with drops of EDT right after spin-coating QDs onto a ZnO-nanoparticle layer. Based on systematic studies on substrate-dependent change in photoluminescence, and current-voltage and luminance–voltage characteristics, we propose that passivation of intra-gap defect states and relative shifts of energy levels relevant to the operation of QD LEDs are two main results of EDT treatment. In particular, we argue that energy-level shift without emission-color change can be attributed to surface-dipole effects.
关键词： quantum-dot LED,1,2-ethanedithiol (EDT) treatment,defect-state passivation,surface-dipole effect,green-emitting CdSe@ZnS
更新于2025-09-19 17:13:59
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Interface Engineering by Thiazolium Iodide Passivation Towards Reduced Thermal Diffusion and Performance Improvement in Perovskite Solar Cells
摘要： Interface engineering has become one of the most facile and effective approaches to improve solar cells performance and its long-term stability and to retard unwanted side reactions. Three passivating agents are developed which can functionalize the surface and induce hydrophobicity, by employing substituted thiazolium iodide (TMI) for perovskite solar cells fabrication. The role of TMI interfacial layers in microstructure and electro-optical properties is assessed for structural as well as transient absorption measurements. TMI treatment resulted in VOC and fill factor enhancement by reducing possible recombination paths at the perovskite/hole selective interface and by reducing the shallow as well as deep traps. These in turn allow to achieve higher performance as compared to the pristine surface. Additionally, the TMI passivated perovskite layer considerably reduces CH3NH3 sion and degradation induced by humidity. The un-encapsulated perovskite solar cells employing TMI exhibit a remarkable stability under moisture levels (≈50% RH), retaining ≈95% of the initial photon current efficiency after 800 h of fabrication, paving the way towards a potential scalable endeavor.
关键词： charge transport,opto-electrical properties,perovskites solar cells,passivation,thin film photovoltaics
更新于2025-09-19 17:13:59
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Optimal Interfacial Engineering with Different Length of Alkylammonium Halide for Efficient and Stable Perovskite Solar Cells
摘要： Recently, two-dimensional (2D) structure on three-dimensional (3D) perovskites (graded 2D/3D) has been reported to be effective in significantly improving both efficiency and stability. However, the electrical properties of the 2D structure as a passivation layer on the 3D perovskite thin film and resistance to the penetration of moisture may vary depending on the length of the alkyl chain. In addition, the surface defects of the 2D itself on the 3D layer may also be affected by the correlation between the 2D structure and the hole conductive material. Therefore, systematic interfacial study with the alkyl chain length of long-chained alkylammonium iodide forming a 2D structure is necessary. Herein, the 2D interfacial layers formed are compared with butylammonium iodide (BAI), octylammonium iodide (OAI), and dodecylammonium iodide (DAI) iodide on a 3D (FAPbI3)0.95(MAPbBr3)0.05 perovskite thin film in terms of the PCE and humidity stability. As the length of the alkyl chain increased from BA to OA to DA, the electron-blocking ability and humidity resistance increase significantly, but the difference between OA and DA is not large. The PSC post-treated with OAI has slightly higher PCE than those treated with BAI and DAI, achieving a certified stabilized efficiency of 22.9%.
关键词： defect passivation,perovskite solar cells,long alkylammonium cations
更新于2025-09-19 17:13:59
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Selfa??Crystallized Multifunctional 2D Perovskite for Efficient and Stable Perovskite Solar Cells
摘要： Recently, perovskite solar cells (PSC) with high power-conversion efficiency (PCE) and long-term stability have been achieved by employing 2D perovskite layers on 3D perovskite light absorbers. However, in-depth studies on the material and the interface between the two perovskite layers are still required to understand the role of the 2D perovskite in PSCs. Self-crystallization of 2D perovskite is successfully induced by deposition of benzyl ammonium iodide (BnAI) on top of a 3D perovskite light absorber. The self-crystallized 2D perovskite can perform a multifunctional role in facilitating hole transfer, owing to its random crystalline orientation and passivating traps in the 3D perovskite. The use of the multifunctional 2D perovskite (M2P) leads to improvement in PCE and long-term stability of PSCs both with and without organic hole transporting material (HTM), 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD) compared to the devices without the M2P.
关键词： trap passivation,hole-transporting layers,hole-transfer facilitators,2D perovskites,perovskite solar cells
更新于2025-09-19 17:13:59
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Ultraviolet-ozone modification on TiO2 surface to promote both efficiency and stability of low-temperature planar perovskite solar cells
摘要： As a classical electron transport layer, the high crystallinity TiO2 has been widely used in perovskite solar cells (PSCs), however, its high-temperature preparation process elevates the fabrication cost and limits its application. Here, we report an ultraviolet-ozone assisted strategy to modify low-temperature TiO2 interface for PSCs. In addition to the more appropriate work function and reinforced built-in potential, the lattice strain of perovskite films crystallized on modified TiO2 has also been released in some degree. Ultrafast transient absorption technique is employed to provide an deep insight into the carrier dynamics, revealing that less non-radiative recombination exists in the modified device. Interestingly, transient surface photovoltage results demonstrate that ultraviolet-ozone modification can efficiently suppress the decomposition of perovskite films under light illumination. Taking advantage of these facts, this device exhibits better efficiency and remarkable stability. This demonstrated low-temperature strategy is a promising way for fabricating low-cost, efficient and stable perovskite device.
关键词： interface passivation,ultraviolet-ozone treatment,photocatalysis,low-temperature TiO2,perovskite solar cells
更新于2025-09-19 17:13:59
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Iodine-assisted Antisolvent Engineering for Stable Perovskite Solar Cells with Efficiency >21.3 %
摘要： The quality of the photoactive film is a significant factor in determining the power conversion efficiency (PCE) and the stability of perovskite solar cells (PSCs). We report a simple upgraded antisolvent washing treatment using iodine modulation, which significantly improves the MAPbI3 films with high crystallinity and chemical uniformity. A detailed model for improving the mechanism is proposed to describe how the upgraded antisolvent enhances both the perovskite crystallization and passivates the under-coordinated Pb2+ dangling bond. PSCs fabricated with the FTO/TiO2/MAPbI3/Spiro-OMeTAD/Ag architecture used high quality films with less defective surfaces, present a PCE of 21.33 %, retaining 91 % of its initial value in ambient without any encapsulation after 30 days. These results provide insight into the surface defect passivation process achieved by halide ions balance while providing a simple and efficient process that can be extensively used to fabricate high-quality perovskite films.
关键词： power conversion efficiency,defect passivation,perovskite solar cells,antisolvent engineering,crystallization
更新于2025-09-19 17:13:59
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Passivation, conductivity, and selectivity in solar cell contacts: Concepts and simulations based on a unified partial-resistances framework
摘要： Passivation, conductivity, and selectivity are often acknowledged as the three requirements for optimal contacts to photovoltaic solar cells. Although there are generally accepted definitions and metrics for passivation and conductivity, a common understanding of the concept of selectivity is emerging only now. In this contribution, we present a generalized model of solar cell contacts based on the distinct lumped resistances encountered by electrons and holes traversing a contact, which we refer to as partial specific contact resistances. The relations between electron and hole partial current densities, quasi-Fermi level separation, and external voltage are derived from these partial specific contact resistances, leading to simple metrics for the aforementioned contact properties: the sum of the electron and hole resistances is a metric for passivation, their ratio is a metric for selectivity, and the majority-carrier resistance is a metric for conductivity. Using PC1D, we validate our model by simulating 10 500 cases of homojunction contacts to crystalline silicon solar cells, although our framework is material agnostic and can be equally applied to any other type of absorber. In these simulations, the hole contact and absorber are assumed to be ideal, whereas we vary the partial specific contact resistances in the electron contact by orders of magnitude by adjusting the electron and hole mobilities, their densities (through variations of the donor doping density), and the contact thickness. The simulations confirm the finding of the model that, when the contact fraction cannot be adjusted—as is the case with full-area contacts—combined passivation and conductivity are necessary and sufficient for optimal solar cell performance, and they imply selectivity. However, the reciprocal is not true: contacts can be selective but lack conductivity—causing a deleterious drop in fill factor—or can be selective but provide poor passivation—leading to a reduction in implied open-circuit voltage and, hence, actual open-circuit voltage. Thus, selectivity is a meaningful metric in the sole case of partial-area contacts, where the contact fraction can be adjusted arbitrarily.
关键词： solar cell contacts,crystalline silicon,partial specific contact resistances,conductivity,selectivity,PC1D simulations,passivation
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Electrical, Computer and Communication Technologies (ICECCT) - Coimbatore, India (2019.2.20-2019.2.22)] 2019 IEEE International Conference on Electrical, Computer and Communication Technologies (ICECCT) - Characterisation and performance evaluation of amorphous silicon nitride as passivation layer in thin film aSi:H solar cells
摘要： The fabrication and characterisation of amorphous silicon nitride layer is presented in this paper. The suitability of using it in photovoltaic application has been investigated. It is observed that the band gap of the nitride layers increases with increase in nitrogen content. The experimental results shows that amorphous silicon nitride alloy can be used as passivation layer in devices due to its high optical band gap. On the basis of experimental results, a thin ?lm aSi:H single junction solar cell having aSiNx as passivation layer has been proposed. Further, the behaviour of the proposed structure has been evaluated through simulation using SCAPS1D solar simulator. It is found out that the involvment of amorphous silicon nitride as passivation layer on the top part of the solar cell results in a conversion ef?ciency of 12.9 % and short circuit current density (Jsc) of 15.18 mA/cm2 which are signi?cant values as far as a single junction amorphous silicon thin ?lm solar cell has been considered. Furthermore, a comparison study on solar cell performance parameters of aSi:H solar cell with and without aSiNx passivation layer has been done.
关键词： composition pro?le,optical band gap,FTIR spectrum,passivation layer,PECVD,conversion ef?ciency
更新于2025-09-16 10:30:52
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MgO/ZnO microsphere bilayer structure towards enhancing the stability of the self-powered MAPbI3 perovskite photodetectors with high detectivity
摘要： In recent years, organic-inorganic hybrid perovskite photodetectors (PDs) have been regarded as promising next-generation PDs. However, the commercialization of the perovskite PDs still faces signi?cant challenges, one of which is the poor stability. Herein, we demonstrate MgO/ZnO microsphere (MS) bilayer structure for improving the device stability with high detectivity. In this MgO/ZnO MS bilayer, ZnO MS array sca?old can facilitate the penetration of perovskite into nano-arrays and bene?ts the light harvest e?ciency due to the special micro-sphere array structure, which behaves a big gap between aligned nanostructures. MgO passivates the interface between ZnO and perovskite, enhancing the device stability and promoting the carrier transport. Finally, our PDs with the bilayer structure exhibit high performance with the on/o? ratio of up to more than 7.0 × 104, the linear dynamic range of 87.7 dB, and the detectivity of 1.5 × 1012 Jones, all of which are better than those of the device without MgO. More importantly, the device with the bilayer structure shows better stability compared with the device without MgO. Under illumination with the optical power of 314 mW/cm2, the photocurrent of the device with MgO shows almost no attenuation after continuous illumination for 30 min. In addition, after storing in air for 15 days, the performance of the device with MgO exhibits slight attenuation and the on/o? ratio is still as high as 2.3 × 104, indicating that the device has good storage stability.
关键词： MgO passivation,Perovskite photodetector,Self-powered,ZnO microsphere
更新于2025-09-16 10:30:52