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Effect of seed layer on growth of rutile TiO <sub/>2</sub> nanorods
摘要: For achieving the high quality of titanium dioxide (TiO2) nanorods, herein, we present a synthesis of rutile TiO2 nanorods on a transparent conductive fluorine-doped tin oxide (FTO) glass substratewith seed layer by a two-step method. TiO2 thin films were first precoated by spin coating and annealing, followed by the growth of TiO2 nanorods with a hydrothermal method. The crystallographic nanostructures and properties of the nanorods were investigated. XRD results demonstrate that seed layer was tetragonal anatase TiO2 structure while nanorods had tetragonal rutile TiO2 structure. Since the hydrothermal technique was conducted in medium acid, structure of nanorods was induced to form in rutile phase. The major characteristic orientation of nanorods on the seed layers was (002) and minor in (101) planes. FE-SEM results show that seed layer enhances the process to achieve vertical-aligned orientation of the TiO2 nanorods, which contribute to develop electron transport rate and could pay an important role inelectron transport layer in high-performance Perovskite solar cell.
关键词: seed layer,hydrothermal method,rutile TiO2 nanorods,Perovskite solar cell,electron transport layer
更新于2025-09-23 15:19:57
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Simple Route to Interconnected, Hierarchically Structured, Porous Zn2SnO4 Nanospheres as Electron Transport Layer for Efficient Perovskite Solar Cells
摘要: Constructing electron transport layer (ETL) with higher carrier mobility and suitable bandgap is of key importance as it greatly influences the photovoltaic performance of perovskite solar cells (PSCs). Zn2SnO4 (ZTO) carries a high electron mobility of 10–30 cm2 V-1 s-1, an order of magnitude over the widely used TiO2 ETL in perovskite solar cells (PSCs), rendering it an excellent alternative to TiO2 ETL. Herein, we report a simple yet robust polymer-templating route to interconnected, hierarchically structured, porous ZTO nanospheres as an efficient ETL for high-performance organolead halide PSCs. The porous ZTO nanospheres ETL, composed of an assembly of 4.5-nm ZTO nanoparticles on the surface of porous nanosphere possessing 80-100 nm cavity, renders markedly improved light absorption, enhanced electron extraction, facilitated charger transportation, and suppressed carrier recombination in the resulting PSCs, which exhibit a power conversion efficiency (PCE) of 17.14%, greatly outperforming the device based on the ZTO nanoparticles (14.02%; i.e., without porosity). As such, the strategy for crafting porous yet hierarchically structured semiconductors with high carrier mobility may open up an avenue to create robust ETL, and by extension, hole transport layer (HTL) for high-performance optoelectronics.
关键词: Zn2SnO4,perovskite solar cells,high electron mobility,hierarchical nanostructure,Electron transport layer
更新于2025-09-23 15:19:57
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High performance CsPbBr <sub/>3</sub> quantum dots photodetectors by using zinc oxide nanorods arrays as an electron-transport layer
摘要: The electron transport layer (ETL) in perovskite photodetectors is playing a vital role in highly efficient electron extraction. Herein, this work reports a perovskite photodetector based on hydrothermal-fabricated ZnO nanorods (NRs) as the ETL and hot-injection-fabricated CsPbBr3 quantum dot (QD) as the photoabsorber. The crystalline structure, morphologies, and photoluminescence (PL) of the materials and the physics mechanism of highly efficient electron extraction in the devices are characterized and analyzed. The PL and time-resolved PL confirm the reduced recombination and enhanced electron transport to the indium tin oxide anode. The photodetectors based on ZnO NRs/CsPbBr3 QDs exhibit enormous enhancement in the response parameters such as a rise time of 12 ms, a decay time of 38 ms, and an on/off ratio of 3000, compared with the photodetectors based on ZnO films/CsPbBr3 QDs. These results indicate that the fabricated ZnO NRs/CsPbBr3 QDs heterojunction has a wide prospect of future applications in photodetectors.
关键词: electron transport layer,photoluminescence,ZnO nanorods,perovskite photodetectors,CsPbBr3 quantum dots
更新于2025-09-23 15:19:57
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The influence of the electron transport layer on charge dynamics and trap-state properties in planar perovskite solar cells
摘要: Despite the outstanding photovoltaic performance of perovskite solar cells, the correlation between the electron transport layer and the mechanism of photoelectric conversion is still not fully understood. In this paper, the relationship between photovoltaic performance and carrier dynamics is systematically studied in both TiO2- and SnO2-based planar perovskite devices. It is found that the different electron transport layers result in distinct forward scan results and charge dynamics. Based on the charge dynamics results, the influence of the electron transport layer on charge carrier transport and charge recombination is revealed. More importantly, the trap-state density is characterized, which is proven to be related to the charge carrier dynamics and the specific hysteresis behaviour in the perovskite solar cells. The present work would provide new insights into the working mechanisms of electron transport layers and their effect on hysteresis.
关键词: electron transport layer,hysteresis,charge dynamics,perovskite solar cells,trap-state properties
更新于2025-09-23 15:19:57
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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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Investigation of the Effects of Various Organic Solvents on the PCBM Electron Transport Layer of Perovskite Solar Cells
摘要: In this study, four organic solvents including 1,2-dichlorobenzene (DCB), chlorobenzene (CB), methylbenzene (MB), and chloroform (CF) were used as solvents in the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) electron transport layer (ETL) of perovskite solar cells (PSCs). This study observed the effects of various solvents on the surface morphology of the ETL by using an optical microscope (OM) and scanning electron microscope (SEM). The surface roughness, crystal structure, and surface element bonding of the ETL were observed using an atomic force microscope (AFM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscope (XPS), respectively. The absorption spectrum of the perovskite layer was explored using an ultraviolet-visible (UV-Vis) spectrometer. The characteristics of the PSC device were analyzed in terms of its current density–voltage (J–V) curve, external quantum efficiency (EQE), and electrochemical impedance spectroscopy (EIS) measurements. The results showed that DCB is a solvent with a high boiling point, low vapor pressure, and high dielectric constant, and using DCB as the solvent for ETL, the uniformity, coverage, and surface roughness of the ETL showed better properties. The power conversion efficiency of the PSC in which DCB was used as the solvent achieved a value of 11.07%, which was higher than that of the PSCs in which other solvents were used.
关键词: organic solvents,perovskite solar cells,1,2-dichlorobenzene,electron transport layer
更新于2025-09-23 15:19:57
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Enhanced efficiency of quantum dot light-emitting diode by sol-gel derived Zn1-xMgxO electron transport layer
摘要: In this study, sol-gel derived Zn1-xMgxO (ZMO) is proposed as an electron transport layer (ETL) for solution-processed quantum-dot light-emitting diodes (QLEDs). It is demonstrated that the increase of Mg content in Zn1-xMgxO films from 0% to 20% causes a dramatic suppression of electron current, which is attributed to the lifting of conduction band minimum and reduction of electron mobility. As a result of Mg-doping, the charge carrier balance might be achieved in the QLED with the Zn0.85Mg0.15O layer resulting in maximum external quantum efficiency of 5.74% and current efficiency of 18 cd·A-1, which are over 3-fold higher than in the case of the device with ZnO layer. Improved device performance is further explained by reduced exciton quenching at QDs/ZMO interface, which is confirmed by time-resolved PL experiments. Obtained results indicate that sol-gel derived ZMO is a promising candidate for ETL in quantum-dot based optoelectronic devices.
关键词: quantum dot,doped zinc oxide,sol-gel process,light-emitting diode,electron transport layer
更新于2025-09-23 15:19:57
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Front contact optimization for rear-junction SHJ solar cells with ultra-thin n-type nanocrystalline silicon oxide
摘要: In this work, ultra-thin n-type hydrogenated nanocrystalline silicon oxide [(nc-SiOx:H (n)] film was used to replace amorphous silicon [a-Si:H (n)] as electron transport layer (ETL) in rear-junction silicon heterojunction (SHJ) solar cell to reduce front parasitic absorption. The contact resistivity between the transparent conductive oxide (TCO) and ultra-thin ETL interface plays an important role on the cell performance. A nanocrystalline silicon (nc-Si:H) contact or seed layer was introduced in the solar cell with ultra-thin nc-SiOx:H and the impact of the nc-Si:H thickness on the cell performance was investigated. To demonstrate scalability, bifacial solar cells with 10 nm ETL were fabricated on the M2 (244 cm2) wafer. The best cell performance is obtained by the solar cell with 5 nm nc-SiOx:H (n) and 5 nm nc-Si:H (n) contact layer and it exhibits open-circuit voltage (Voc) of 738 mV, fill factor (FF) of 80.4%, short-circuit current density (Jsc) of 39.0 mA/cm2 and power conversion efficiency (η) of 23.1% on M2 wafer. Compared to the one with nc-SiOx:H (n), an increase of 3%abs of FF and 0.5%abs of η and lower front contact resistivity is demonstrated for the solar cells with nc-Si:H (n) / nc-SiOx:H (n) double layer, which is caused by the lower energy barrier for electrons, according to the band diagram calculated by the AFORS-HET simulator. A simulation on the solar cell optical and electrical losses was done by the Quokka 3 simulator and shows much lower electrical transport loss and a bit higher front surface transmission loss for the one with double layer than nc-SiOx:H (n) single layer.
关键词: Loss analysis,Nanocrystalline silicon oxide,Silicon heterojunction solar cells,Electron transport layer
更新于2025-09-23 15:19:57
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[IEEE 2020 IEEE Latin America Electron Devices Conference (LAEDC) - San Jose, Costa Rica (2020.2.25-2020.2.28)] 2020 IEEE Latin America Electron Devices Conference (LAEDC) - Impact of the Hafnium Oxide as Hole Blocking Layer on the Performance of Organic Solar Cells
摘要: The effects of hafnium oxide (HfO2) as hole blocking layer (HBL) on the stability and degradation under air environment of inverted bulk heterojunction organic solar cells (iOSC), using as donor material thieno[3,4b]thiophene-alt-benzodithiophene (PTB7) and as acceptor material [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) are presented. The ultrathin films of HfO2 layers 0.9 nm of thick were deposited by thermal evaporation. The highest power conversion efficiency obtained (PCE) was of 8.33%. The current density-voltage characteristic (J-V) was modeled through the ideal-diode equivalent circuit model. For comparison, cells with poly [(9,9-bis (30- (N,N-dimethylamino) propyl) -2,7-fluorene) -alt-2,7- (9,9-dioctylfluorene)] (PFN) and Zinc Oxide (ZnO) as hole blocking layer were fabricated. The three groups of cells were exposed to air for 1000 h. The electrical parameters extracted from the current density–voltage characteristic (J–V) were analyzed. The PCE for cells manufactured with HfO2 as HBL remains around 30% after 1000 h under air environment, showing less degradation than iOSCs with ZnO.
关键词: electron transport layer,HfO2,PFN,PTB7:PC70BM solar cells,hafnium oxide,organic solar cells,ZnO,Degradation,OSC stability
更新于2025-09-23 15:19:57
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Plasmonic gold nanorods mediated p-BFCrO/n-rGO heterojunction in realizing efficient ferroelectric photovoltaic devices
摘要: In this work, we introduce a chemically synthesised lead-free ferroelectric thin film 2% Cr doped BiFeO3 (BFCrO) for possible photovoltaic (PV) applications. The first set of PV devices were fabricated onto ITO/glass electrode by utilizing BFCrO as an active material and Pt as top electrode. The obtained ferroelectric and electrical results were systematically compared with the conventional BFO and the BFCrO device was found to be a potential one. To further enhance the PV performance, highly conducting n-type reduced graphene oxide (rGO) was heterogeneously employed as an electron transport layer (ETL) in between ITO and BFCrO. Surprisingly, the JSC was significantly improved by 1000 times along with amended VOC and FF as compared to the standalone BFCrO device. Furthermore, an attempt has been made to embed plasmonic Au nanorods (NRs) in between rGO and BFCrO, which alleviates the absorbance in heterojunction through localized surface plasmonic effect, ultimately offered remarkable PV performances than conventional BFO one. The Au NRs based BFCrO/rGO PV device exhibited an increased VOC and JSC of 0.63 V and 2.56 mA/cm2, respectively as compared to the BFCrO/rGO device with VOC (0.56 V) and JSC (1.54 mA/cm2). Effort was devoted to establish ferroelectricity in BFCrO and the effect of positive and negative polarizations on J-V measurements were observed in with or without Au NRs based devices. The modulation in charge transport with polarization field and improved photoresponse were explained by projecting a band diagram, which also provides a comprehensive understanding on the operation principle of the fabricated devices.
关键词: Ferroelectric polarization,Heterointerface,Photovoltaic effect,Electron transport layer,Plasmon resonance
更新于2025-09-19 17:13:59