- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effects of interfacial energy level alignment on carrier dynamics and photovoltaic performance of inverted perovskite solar cells
摘要： Metal doping is an efficient method for optimizing NiOx as hole transport material in the inverted perovskite solar cells, which can contribute to the optimization of the interfacial energy level alignment, while the underlying influencing mechanism on the charge carrier dynamics and device performance needs to be further elucidated. In this work, NiOx films with modulated energy levels are obtained via Li doping and examined by ultraviolet photoelectron spectrometer. The effects of the energy level alignment of NiOx on the carrier transfer and recombination dynamics are elucidated by transient photovoltage/photocurrent and transient fluorescence dynamics. The Li doping can significantly shift the valence band of NiOx downward, and the 4% Li content endows NiOx with the optimal energy level matching with perovskite and the best charge separation/transfer ability, which can be confirmed through the photoluminescence results. The corresponding device possesses superior photovoltaic parameters with the champion power conversion efficiency of 17.34%, 37% higher than device based on pure NiOx. The results highlight that proper metal doping can optimize the energy level of the hole transport material to well match the perovskite, thus efficiently promoting charge separation and inhibiting charge recombination, which leads to the enhancement of the device performances.
关键词： Li-doped NiOx,Inverted perovskite solar cell,Charge transport/recombination dynamics,Energy level alignment
更新于2025-09-19 17:13:59
-
Determination of band alignment at the CdTe/SnTe heterojunction interface for CdTe thin-film solar cells
摘要： The Ohmic back contact for CdTe is a key issue to realize high-efficiency CdTe thin film solar cells because of the high work function of CdTe. CdTe/SnTe heterojunctions (HJs) have been implemented to address this issue which shows promising potential, but the band alignment at the HJs is unknown. The valence band offsets in MBE-grown cadmium telluride (CdTe)/tin telluride (SnTe) (111) heterostructures were measured with X-ray photoelectron spectroscopy (XPS). The XPS results show that the heterostructure has an ideal type-I band structure for CdTe solar cells applications, with a valence band offset of ?1.33 ± 0.18 eV and a conduction band offset of 0.09 ± 0.18 eV, which expedites hole transport from the CdTe absorber to the hole electrode and improves the Ohmic contact for CdTe. Experimental determination of the band structure of CdTe/SnTe HJs can help improve the photovoltaic performance of CdTe thin film solar cells and facilitate the design and fabrication of CdTe/SnTe related devices. Furthermore, we inserted a SnTe back contact buffer layer into the CdTe thin film solar cells, and it was compared with the cell structure without the SnTe buffer layer. The feasibility of using SnTe as a solar cell back contact is confirmed.
关键词： solar cells,CdTe,heterojunction,band alignment,XPS,SnTe
更新于2025-09-19 17:13:59
-
Sandwich-like electron transporting layer to achieve highly efficient perovskite solar cells
摘要： Passivating the carrier recombination at the heterojunction interface and improving the efficiency of charge separation are effective means to boost the performance of perovskite solar cells (PSCs). The interface modification between the anode and the electron transporting layer (ETL) or constructing bilayer structural ETLs has been proved to be the effective way to achieve high-efficient charge extraction and collection. Combining the advantages of both techniques might further achieve lower energy loss and higher efficiency in PSCs. Herein, we design a sandwich-like SnO2-CQDs-SnO2 (S–C–S) ETLs, i.e. an ultrathin band-gap tunable carbon quantum dots (CQDs) layer is inserted between ultrathin SnO2 bottom layer and SnO2 top layer. The bottom ultrathin SnO2 layer passivates the defects of SnO2:F (FTO) and reduces the carrier recombination at the FTO/ETLs interface. The CQDs layer enhances the optical transmission of ETLs, accelerates carrier transport process and improves the hole-blocking ability. Such S–C–S ETLs greatly enhance the power conversion efficiency (PCE) of PSCs and eliminate hysteresis to the maximum extent. This work provides a new concept for designing novel electronic transmission materials for solar cells, and lays the foundation for further achieving higher PCE in PSCs.
关键词： Power conversion efficiency,Sandwich-like electron transporting layer,Band alignment,Perovskite solar cell,Interface modification
更新于2025-09-19 17:13:59
-
Interfacial Energy Level Tuning for Efficient and Thermostable CsPbI <sub/>2</sub> Br Perovskite Solar Cells
摘要： Inorganic mixed-halide CsPbX3-based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic–inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol–gel-derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3-doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open-circuit voltage of 1.28 V, together with an increase in fill factor and short-circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3-doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C.
关键词： energy level alignment,flexible perovskite solar cells,thermal stability,all-inorganic perovskite solar cells
更新于2025-09-19 17:13:59
-
Insights from Device Modeling of Perovskite Solar Cells
摘要： In this perspective, we explore the insights into the device physics of perovskite solar cells gained from modeling and simulation of these devices. We discuss a range of factors that influence the modeling of perovskite solar cells, including the role of ions, dielectric constant, density of states, and spatial distribution of recombination losses. By focusing on the effect of non-ideal energetic alignment in perovskite photovoltaic devices, we demonstrate a unique feature in low recombination perovskite materials – the formation of an interfacial, primarily electronic, self-induced dipole that results in a significant increase in the built-in potential and device open-circuit voltage. Finally, we discuss the future directions of device modeling in the field of perovskite photovoltaics, describing some of the outstanding open questions in which device simulations can serve as a particularly powerful tool for future advancements in the field.
关键词： device physics,density of states,simulation,device modeling,recombination losses,dielectric constant,perovskite solar cells,energetic alignment
更新于2025-09-19 17:13:59
-
Corrections to a??Highly Conductive and Broadband Transparent Zr-Doped In <sub/>2</sub> O <sub/>3</sub> as Front Electrode for Solar Cellsa?? [Sep 18 1202-1207]
摘要： An intelligent hybrid Taguchi-genetic algorithm (IHTGA) is used to optimize bearing offsets and shaft alignment in a marine vessel propulsion system. The objectives are to minimize normal shaft stress and shear force. The constraints are permissible reaction force, bearing stress, shear force, and bending moment in the shaft thrust ?ange under cold and hot operating conditions. Accurate alignment of the shaft for a main propulsion system is important for ensuring the safe operation of a vessel. To obtain a set of acceptable forces and stresses for the bearings and shaft under operating conditions, the optimal bearing offsets must be determined. Instead of the time-consuming classical local search methods with some trial-and-error procedures used in most shipyards to optimize bearing offsets, this paper used IHTGA. The proposed IHTGA performs Taguchi method between the crossover operation of the conventional GA. Incorporating the systematic reasoning ability of Taguchi method in the crossover operation enables intelligent selection of genes used to achieve crossover, which enhances the performance of the IHTGA in terms of robustness, statistical performance, and convergence speed. A penalty function method is performed using the ?tness function as a pseudo-objective function comprising a linear combination of design objectives and constraints. A ?nite-element method is also used to determine the reaction forces and stresses in the bearings and to determine normal stresses, bending moments, and shear forces in the shaft. Computational experiments in a 2200 TEU container vessel show that the results obtained by the proposed IHTGA are signi?cantly better than those obtained by the conventional local search methods with some trial-and-error procedures.
关键词： genetic algorithm,shaft alignment,Marine vessel propulsion system,bearing offsets,optimal design
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Large Area 21.6% Efficiency Front Junction N-type Cell with Screen Printed Tunnel Oxide Passivated Poly-Si Rear Contact
摘要： Blind interference alignment (BIA) can greatly improve the degree of freedom with the infinite signal-to-noise ratio (SNR) assumption. Under the finite SNR condition, noise accumulation can have a significantly negative impact on SNR, inducing severe performance deterioration. In particular, in multi-cell networks, the transmitter to which a user connects can further affect its received SNR and the BIA design. To address such problem, we present a user grouping scheme for reducing noise accumulation in a single cell and analyze the impact of transmitter connections on the user grouping scheme. SNR BIA in a multi-cell network is further proposed, which jointly optimizes the transmitter connection and the user grouping scheme. Extensive simulations demonstrate that the achievable sum rate of SNR BIA is 1.36 times, 1.66 times, and 2.68 times that of data shared BIA, standard BIA, and extended BIA reported in the literature, respectively, and SNR BIA is more robust to user mobility.
关键词： transmitter connection,SNR reduced factor,effective degree of freedom,Blind interference alignment
更新于2025-09-19 17:13:59
-
Sonication-Enhanced Alignment Relay Technique for the Orientation of Single-Walled Carbon Nanotubes
摘要： The high demand for thin, lightweight yet fast and e?cient devices is a driving force behind the miniaturization trend in the electronics industry. Speci?cally, the advancement of semiconducting single-walled carbon nanotubes (SWNTs) can continue to revolutionize transistors, although there are still many challenges ahead. We have previously reported an alignment relay technique (ART) that is capable of simultaneously controlling the alignment, length, and diameter of surface deposited SWNTs. However, the current technique yields inconsistencies in orientation, lengths of tubes, and their density. Here, we present a reviewed ART protocol that includes sonication for improved selectivity. We show that the SWNTs average alignment increased from 40% to 77% within a 10° range in orientation with sonication times as low as 5 min. Sonication generated larger diameter nanotubes on the surface, with a preference for semiconducting chiral tubes in the range of 1.44?1.61 nm in diameter. Consequently, simple alterations to the standard alignment relay technique can prove to be prosperous in improving selectivity and orientational control of single-walled carbon nanotubes. This work has direct impact for the simultaneous control of nanotube alignment and nanotube chiralities.
关键词： alignment relay technique,iptycenes,alignment,sonication,single-walled carbon nanotubes,surface chemistry,liquid crystals
更新于2025-09-16 10:30:52
-
The effect of introducing antibiotics into organic light-emitting diodes
摘要： The quest to improve the performance of organic light-emitting diodes (OLEDs) has led to the exploration of new materials with properties like interfacial dipole, excitons generation, and bandgap alignment. Here, we exploit these strategies by investigating the interaction of the antibiotic ampicillin with a widely used optoelectronic material, to fabricate state-of-the-art OLEDs. The charge distribution on the ampicillin molecule facilitates the generation of an interfacial dipole with a large magnitude. The optimum fusion of the two materials provides an enhanced bandgap alignment, charge balance and J/H-aggregated excitons. Values of current efficiency (120 cdA?1), external quantum efficiency (~35%) and power efficiency (70 lmW?1) are demonstrated. The cross-evaluation of performance with penicillin devices indicates the significance of ampicillin’s specific molecular structure in improving performance. The detailed investigations demonstrate that ampicillin has superior optoelectronic properties with high potential to contribute extensively in OLEDs and photovoltaics.
关键词： OLEDs,interfacial dipole,bandgap alignment,exciton generation,ampicillin
更新于2025-09-16 10:30:52
-
Energy level alignment and nanoscale investigation of a-TiO <sub/>2</sub> /Cu-Zn-Sn-S interface for alternative electron transport layer in earth abundant Cu-Zn-Sn-S solar cells
摘要： Efficiency of earth abundant and pure sulfide kesterite Cu-Zn-Sn-S (CZTS) solar cell has been stagnant around 9.4% for years, while its counterpart Cu-In-Ga-Se (CIGS) reports an efficiency of more than 22%. Low open circuit voltage (VOC) is the major challenging factor for low efficiency due to severe nonradiative interface recombinations. The existence of higher defect states at the conventional CZTS-CdS interface due to undesirable energy level alignment and lattice misfit promotes trap-assisted recombinations and results in low VOC. In this work, amorphous TiO2 (Eg = 3.8 eV) is proposed as a promising substitute to the conventional and low bandgap CdS (Eg = 2.4 eV) layer. The surface and interface of the CZTS-TiO2 layer were investigated using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The result reveals favorable "spike"-like conformations at the CZTS-TiO2 interface with a conduction band offset value of 0.17 eV. The nanoscale probing of the interface by Kelvin probe force microscopy across CZTS-TiO2 layers shows a higher potential barrier for interface recombination at CZTS-TiO2 in contrast to the conventional CZTS-CdS interface. Finally, the fast decay response and lower persistent photoconductivity of photogenerated carriers for CZTS-TiO2 heterojunction based photodetectors further validate our results. The energy level alignment and nanoscale interface studies signify TiO2 as a promising alternate buffer layer for earth abundant CZTS solar cells.
关键词： XPS,TiO2,CZTS,CdS,energy level alignment,KPFM,UPS,solar cells,interface recombination
更新于2025-09-16 10:30:52