By introducing bromobenzoic acid (BAC) into the perovskite precursor solution, the micro-strain in the perovskite film was effectively relieved. This additive improved the PCE to 24.02% ultimately.
The metal materials with high work function should be used as the back electrode of CdTe solar cells. In the present paper, the back contact performances of CdTe solar cells with Au film and Ni film, respectively, were studied by X-ray photoelectron spectrum (XPS). After exfoliating the back electrode film, it was found that Au on the surface of ZnTe/ZnTe:Cu complex back contact layer is in the form of Au atoms and the concentration and depth of Ni diffusing into the ZnTe/ZnTe:Cu back contact layer are higher than that of Au. What's more, some Ni changes into Ni(x)+ ion which leads to rich Te ions in ZnTe/ZnTe:Cu back contact layer. So the diffusing concentration is increased, which makes the characters of CdTe improved. In the samples, the displacement of either Te or Zn peak position changes little, which indicates that both Te and Zn do not change in the modality.
This article presents a high accurate numerical algorithm for solving the two-dimensional regularized long-wave equation. After first deforming the original equation, the fourth-order compact difference scheme and the fourth-order Pad´e scheme are respectively employed to discretize the spatial second and first derivatives in this deformed equation, and the temporal derivative term is discretized in the θ-weighted scheme. The nonlinear terms in the scheme are linearized using the Taylor series expansion method. The results show that the order of convergence of the proposed method is O(τ 2+ h 4 x + h 4 y). Using a discrete energy method and mathematical induction, the existence, uniqueness, and conservation of energy of the numerical solution are proved. The new scheme is conservative and unconditionally stable. Finally, the numerical stability and accuracy of this method are verified through some numerical experiments.
Wider band-gap window layers can enhance the transmission of sunlight in the short-wavelength region and improve the performance of CdTe solar cells. In this work, we investigated the band structure of In-doped Zn 1−x Mg x O (ZMO:In) by using first-principles calculations with the GGA + U method and simulated the performance of ZMO:In/CdTe devices using the SCAPS program. The calculation results show that with the increased Mg doping concentration, the band gap of ZMO increases. However, the band gap of ZMO was decreased after In incorporation due to the downwards shifted conduction band. Owing to the improved short circuit current and fill factor, the conversion efficiency of the ZMO:In-based solar cells show better performance as compared with the CdS-based ones. A highest efficiency of 19.63% could be achieved owing to the wider band gap of ZMO:In and the appropriate conduction band offset (CBO) of ~0.23 eV at ZMO:In/CdTe interface when the Mg concentration x approaches 0.0625. Further investigations on thickness suggest an appropriate thickness of ZMO:In (x = 0.0625) in order to obtain better device performance would be 70–100 nm. This work provides a theoretical guidance for designing and fabricating highly efficient CdTe solar cells.
Abstract The Cs 3 Bi 2 I 9 single crystal, as an all‐inorganic non‐lead perovskite, offers advantages such as stability and environmental friendliness. Its superior photoelectric properties, attributed to the absence of grain boundary influence, make it an outstanding X‐ray detection material compared to polycrystals. In addition to material properties, X‐ray detector performance is affected by the thickness of the absorption layer. Addressing this, a space‐confined method is proposed. The temperature field is determined through finite element simulation, effectively guiding the design of the space‐confined method. Through this innovative method, a series of thickness‐controlled perovskite single crystal wafers (PSCWs) are successfully prepared. Corresponding X‐ray detectors are then prepared, and the impact of single crystal thickness on device performance is investigated. With an increase in single crystal thickness, a rise followed by a decline in device sensitivity is observed, reaching an optimal value at 0.7 mm thickness at 40V mm −1 with a device performance of 11313.6µC Gy −1 cm −2 . This space‐confined method enables the direct growth of high‐quality perovskite single crystals with specified thickness, eliminating the need for slicing or etching.
Tin oxide SnO 2 films were prepared by RF magnetron sputtering. The effects of oxygen partial pressure percentage on the SnO 2 property have been investigated to obtain relatively high-resistivity SnO 2 films which could be used as buffer layers to optimize the performance of CdTe/CdS solar cells. The oxygen partial pressure percentage varied in the range of 1% ~ 10%. The results show that the introduction of oxygen would suppress the deposition and growth of SnO 2 films. Electrical measurement suggests that the film resistivity decreases with the increase of oxygen pressure. The SnO 2 films with resistivity of 232 Ω cm were obtained in pure Ar atmosphere. All SnO 2 films fabricated with different oxygen partial pressure percentage have almost the same optical band gap.
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