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- 实验方案
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Highly Stable Red Quantum Dot Light Emitting Diodes with Long T <sub/>95</sub> Operation Lifetime
摘要： Quantum dot light-emitting diodes (QLEDs) with excellent performances such as external quantum efficiency (EQE) and lifetime have almost met the requirement of low brightness display. However, the short operation lifetime under high brightness limits the application of QLEDs in outdoor displays and lightings. Herein, we report a highly efficient, stable red QLED by using of lithium and magnesium co-doped as well as magnesium oxide shell-coated zinc oxide nanoparticle layer as electron transport layer (ETL). The optimized QLED has a high peak EQE of 20.6%, a low efficiency roll-off at high current, and a remarkably long lifetime T95 > 11000 h at 1000 cd m-2, which indicates the realization of the most stable red QLED up to now. The improvement in the long-term stability of the QLED is attributed to the use of co-doped and shell-coated zinc oxide ETL with reduced electron injection to improve the charge balance in device.
关键词： EQE,QLEDs,electron transport layer,ETL,magnesium oxide shell-coated zinc oxide,Quantum dot light-emitting diodes,external quantum efficiency,lithium and magnesium co-doped,ZLMO@MO,lifetime
更新于2025-09-23 15:21:01
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RbF modified FTO electrode enable energy-level matching for efficient electron transport layer-free perovskite solar cells
摘要： The development of highly efficient electron transport layer free perovskite solar cells (ETL-free PSCs) with simplified and economical device configurations can significantly motivate the commercialization of PSCs. However, the performance of ETL-free PSCs has been hampered by the sluggish charge extraction and severe charge carrier recombination due to the energy-level mismatch at the interface of the perovskite and the transparent conductive electrode FTO (fluorine doped tin-oxide). In this study, this issue is well solved by modifying the FTO surface with a simple, low-cost and non-toxic rubidium fluoride (RbF) interlayer. An interfacial dipole layer is formed on the FTO surface by inserting a RbF layer, which tunes the work function of FTO, eliminates the electron transport barrier and optimizes the energy-level alignment at the FTO/perovskite interface, thereby enhancing the charge transfer and suppressing the carrier recombination. Consequently, the rigid ETL-free PSCs with RbF layer yield high efficiencies of up to 18.79%, higher than that of ETL-free devices on bare FTO (16.03%). By virtue of the low-temperature processability, a superior PCE of 15.7% has been achieved by flexible ETL-free PSCs fabricated on RbF modified plastic substrate. This study provides a simple, efficient and environmentally friendly approach to modify the FTO electrode for fabricating ETL-free PSCs, which contribute to promote the design of advanced interface materials for simplified and high-performance perovskite photovoltaics.
关键词： ETL-Free Perovskite Solar Cells,Interface Dipole,Energy-Level Matching,Aqueous Processing
更新于2025-09-23 15:21:01
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Double Metal Oxide Electron Transport Layers for Colloidal Quantum Dot Light-Emitting Diodes
摘要： The performance of colloidal quantum dot light-emitting diodes (QD-LEDs) have been rapidly improved since metal oxide semiconductors were adopted for an electron transport layer (ETL). Among metal oxide semiconductors, zinc oxide (ZnO) has been the most generally employed for the ETL because of its excellent electron transport and injection properties. However, the ZnO ETL often yields charge imbalance in QD-LEDs, which results in undesirable device performance. Here, to address this issue, we introduce double metal oxide ETLs comprising ZnO and tin dioxide (SnO2) bilayer stacks. The employment of SnO2 for the second ETL significantly improves charge balance in the QD-LEDs by preventing spontaneous electron injection from the ZnO ETL and, as a result, we demonstrate 1.6 times higher luminescence efficiency in the QD-LEDs. This result suggests that the proposed double metal oxide ETLs can be a versatile platform for QD-based optoelectronic devices.
关键词： metal oxide,light emitting diode (LED),SnO2 nanoparticles,quantum dot (QD),double electron transport layer (ETL)
更新于2025-09-23 15:19:57
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Influence of Electron Transport Layer (TiO2) Thickness and Its Doping Density on the Performance of CH3NH3PbI3-Based Planar Perovskite Solar Cells
摘要： Simulation studies are vital to understanding solar cell performance and in optimal device design for high-efficiency solar cells. Cell performance is sensitive to many factors, including device architecture, energy band alignment at the interfaces, materials used for photogeneration, charge extraction, doping density and thickness of various layers. The role of electron transport layer (ETL) thickness and its doping density on device performance is explored in this work. As the ETL thickness is increased from 10 nm to 200 nm, both fill factor (FF) and efficiency remain high up to 40 nm, at 0.85 and 28.04%, respectively, and beyond 40 nm, they decrease gradually due to a sharp increase in series resistance, reaching zero at 200 nm. However, Jsc and Voc remained unchanged up to an ETL thickness of about 150 nm and 160 nm, respectively. These results were confirmed by contour plots of the simulated Voc, Jsc, FF and efficiency results. We observed that when ETL approached 200 nm, Jsc and Voc decreased to zero and 0.88 V, respectively. This can be attributed to very high series resistance and recombination in the cell. Donor concentration variation in the ETL from 1017/cm3 to 1020/cm3 has much less impact on Jsc, and Voc remains unchanged. However, fill factor and efficiency improved, which might be due to an increase in conductivity in the ETL. Our result shows that for an optimized device, with an AM 1.5 spectrum, a cell efficiency of 29.64% was achieved with Voc, Jsc and fill factor of 1.241 V, 28.70 mA/cm2 and 0.83, respectively.
关键词： contour map,ETL doping density,light I–V,ETL thickness,CH3NH3PbI3
更新于2025-09-19 17:13:59
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Enhanced Lifetime and Photostability with Low-temperature Mesoporous ZnTiO3/Compact SnO2 Electrodes in Perovskite Solar Cells
摘要： Perovskite solar cells (PSC) which have exceeded power conversion efficiencies (PCEs) of 25% are mainly demonstrated by using SnO2 or TiO2 as electron-transporting layers (ETLs). However, high-performance planar PSCs need precise process, which is difficult for large-scale production. Mesoporous structure shows better operability but with high-temperature process. Besides, as the most used mesoporous materials, the strong photocatalytic effect of TiO2 significantly limits the practical stability of PSCs under illumination (including ultraviolet light). Here we propose Zinc Titanate (ZnTiO3, ZTO) as mesoporous ETLs due to its weak photo-effect, excellent carrier extraction and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150°C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2-mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5%. The PSCs retained more than 95% of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95% of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5G illumination (100 mW cm-2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. Moreover, the low temperature deposition method of inorganic ETL furnishes a way of low power consumption, large-scale and flexible preparation of PSCs.
关键词： perovskite solar cell,photostability,ZTO,low-temperature,mesoporous ETL
更新于2025-09-19 17:13:59
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Spray-coated SnO2 electron transport layer with high uniformity for planar perovskite solar cells
摘要： SnO2 has been proven to be an effective electron transport layer (ETL) material for perovskite solar cells (PSCs) owing to its excellent electrical and optical properties. Here, we introduce a viable spray coating method for the preparation of SnO2 films. Then, we employ a SnO2 film prepared using the spray coating method as an ETL for PSCs. The PSC based on the spray-coated SnO2 ETL achieves a power conversion efficiency of 17.78%, which is comparable to that of PSCs based on conventional spin-coated SnO2 films. The large-area SnO2 films prepared by spray coating exhibit good repeatability for device performance. This study shows that SnO2 films prepared by spray coating can be applied as ETLs for stable and high-efficiency PSCs. Because the proposed method involves low material consumption, it enables the low-cost and large-scale production of PSCs.
关键词： SnO2 film,PSCs,ETL,spray coating
更新于2025-09-19 17:13:59
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Zwitterion Nondetergent Sulfobetaine-Modified SnO <sub/>2</sub> as an Efficient Electron Transport Layer for Inverted Organic Solar Cells
摘要： Tin oxide (SnO2) has been widely accepted as an effective electron transport layer (ETL) for optoelectronic devices because of its outstanding electro-optical properties such as its suitable band energy levels, high electron mobility, and high transparency. Here, we report a simple but effective interfacial engineering strategy to achieve highly efficient and stable inverted organic solar cells (iOSCs) via a low-temperature solution process and an SnO2 ETL modified by zwitterion nondetergent sulfobetaine 3-(4-tert-butyl-1-pyridinio)-1-propanesulfonate (NDSB-256-4T). We found that NDSB-256-4T helps reduce the work function of SnO2, resulting in more efficient electron extraction and transport to the cathode of iOSCs. NDSB-256-4T also passivates the defects in SnO2, which serves as recombination centers that greatly reduce the device performance of iOSCs. In addition, NDSB-256-4T provides the better interfacial contact between SnO2 and the active layer. Thus, a higher power conversion efficiency (PCE) and longer device stability of iOSCs are expected for a combination of SnO2 and NDSB-256-4T than for devices based on SnO2 only. With these enhanced interfacial properties, P3HT:PC60BM-based iOSCs using SnO2/NDSB-256-4T (0.2 mg/mL) as an ETL showed both a higher average PCE of 3.72%, which is 33% higher than devices using SnO2 only (2.79%) and excellent device stability (over 90% of the initial PCE remained after storing 5 weeks in ambient air without encapsulation). In an extended application of the PTB7-Th:PC70BM systems, we achieved an impressive average PCE of 8.22% with SnO2/NDSB-256-4T (0.2 mg/mL) as the ETL, while devices based on SnO2 exhibited an average PCE of only 4.45%. Thus, the use of zwitterion to modify SnO2 ETL is a promising way to obtain both highly efficient and stable iOSCs.
关键词： inverted organic solar cells (iOSCs),zwitterion nondetergent sulfobetaine (NDSB-256-4T),Tin oxide (SnO2),power conversion efficiency (PCE),electron transport layer (ETL)
更新于2025-09-12 10:27:22
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Improvement of photovoltaic performance of perovskite solar cells by interface modification with CaTiO3
摘要： The ETL/perovskite interface is crucial for the photovoltaic performance of perovskite solar cells (PSCs) because of its key role in electrons transport and charge recombination. Herein, an ultrathin CaTiO3 layer has facilely been fabricated and incorporated between the mp-TiO2 and perovskite layers. Due to the trap passivation effect and the optimized energy level alignment induced by modification, the electron transport is facilitated while the charge recombination is suppressed effectively. Therefore, the champion device gains a maximum PCE of 19.12% with the enhanced photovoltaic performance. In addition, the stability of PSCs has also been ameliorated by modification, and about 85% of the initial efficiency can be maintained even after exposure in ambient for 1000h.
关键词： CaTiO3,Perovskite solar cell,ETL,Interface modification
更新于2025-09-12 10:27:22
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Enhanced Lifetime and Photostability with Low‐temperature Mesoporous ZnTiO3/Compact SnO2 Electrodes in Perovskite Solar Cells
摘要： Perovskite solar cells (PSC) which have exceeded power conversion efficiencies (PCEs) of 25% are mainly demonstrated by using SnO2 or TiO2 as electron-transporting layers (ETLs). However, high-performance planar PSCs need precise process, which is difficult for large-scale production. Mesoporous structure shows better operability but with high-temperature process. Besides, as the most used mesoporous materials, the strong photocatalytic effect of TiO2 significantly limits the practical stability of PSCs under illumination (including ultraviolet light). Here we propose Zinc Titanate (ZnTiO3, ZTO) as mesoporous ETLs due to its weak photo-effect, excellent carrier extraction and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150°C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2-mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5%. The PSCs retained more than 95% of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95% of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5G illumination (100 mW cm-2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. Moreover, the low temperature deposition method of inorganic ETL furnishes a way of low power consumption, large-scale and flexible preparation of PSCs.
关键词： perovskite solar cell,mesoporous ETL,photostability,ZTO,low-temperature
更新于2025-09-11 14:15:04
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Influence of PbS Quantum Dots-Doped TiO2 Nanotubes in TiO2 Film as an Electron Transport Layer for Enhanced Perovskite Solar Cell Performance
摘要： Lead sulfide quantum dots-doped titanium dioxide nanotubes (PbS QDs-doped TNTs) were successfully prepared by the hydrothermal and impregnation methods. A thin layer of titanium dioxide (TiO2) comprising of PbS QDs-doped TNTs was applied as an electron transport layer (ETL) in order to improve the planar perovskite solar cell efficiency. The role of incorporating a high surface area of one-dimensional nanotube structure of TiO2 in the conventional TiO2 layer provided a special unidirectional charge transport and a high charge collection. Moreover, doping PbS QDs onto the surface of TNTs modified the electronic and optical properties of the ETL by downshifting the conduction band of TiO2 from ?4.22 to ?4.58 eV, therefore promoting the driving force of an electron injection to the transparent conductive electrode. By varying the concentration of PbS QDs-doped TNTs dispersed in 2-butanol from 0.1 to 0.9 mg/mL, a concentration of 0.3 mg/mL PbS QDs-doped TNTs was the optimum concentration to be mixed with TiO2 solution for the ETL deposition. The best perovskite solar cell performance with the optimum loading of PbS QDs-doped TNTs provided 14.95% power conversion efficiency, which was increased from 12.82% obtained from the cell with pristine TiO2 film as ETL.
关键词： PbS quantum dots (PbS QDs),perovskite solar cells (PSCs),TiO2 nanotubes (TNTs),Electron transport layer (ETL)
更新于2025-09-11 14:15:04