The effect of post-annealing on the performance of the CuZnSnS solar cells.

CuZnSnS (CZTS) solar cells commonly undergo post-annealing treatments to enhance their performance. However, multiple concurrent effects, including Cu-Zn disorder, Na diffusion from the back contact, CZTS grain boundary passivation, and elemental interdiffusion at the CdS/CZTS interface, can occur simultaneously during post-annealing, making it challenging to isolate their specific influence on device performance. To address this complexity, we have utilized Cu-Zn-disordered CZTS absorbers to eliminate the influence of Cu-Zn disorder in this study.

Combining experiments on luminescent centres in hexagonal boron nitride with the polaron model and methods towards the identification of their microscopic origin.

The two-dimensional material hexagonal boron nitride (hBN) hosts luminescent centres with emission energies of ∼2 eV which exhibit pronounced phonon sidebands. We investigate the microscopic origin of these luminescent centres by combining calculations with non-perturbative open quantum system theory to study the emission and absorption properties of 26 defect transitions. Comparing the calculated line shapes with experiments we narrow down the microscopic origin to three carbon-based defects: CC, CC, and VC.

Molybdenum Disulfide Nanoribbons with Enhanced Edge Nonlinear Response and Photoresponsivity.

MoS nanoribbons have attracted increased interest due to their properties, which can be tailored by tuning their dimensions. Herein, the growth of MoS nanoribbons and triangular crystals formed by the reaction between films of MoOx (2 View Article and Find Full Text PDF

A facile strategy for the growth of high-quality tungsten disulfide crystals mediated by oxygen-deficient oxide precursors.

Chemical vapor deposition (CVD) has been established as a versatile route for the large-scale synthesis of transition metal dichalcogenides, such as tungsten disulfide (WS). Yet, the precursor composition's role on the CVD process remains largely unknown and remains to be explored. Here, we employ Pulsed Laser Deposition (PLD) in a two-stage approach to tune the oxygen content in the tungsten oxide (WO) precursors and demonstrate the presence of oxygen vacancies in the oxide films leads to a more facile conversion from WO to WS.

Gettering in PolySi/SiO Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience.

Multijunction solar cells in a tandem configuration could further lower the costs of electricity if crystalline Si (c-Si) is used as the bottom cell. However, for direct monolithic integration on c-Si, only a restricted number of top and bottom cell architectures are compatible, due to either epitaxy or high-temperature constraints, where the interface between subcells is subject to a trade-off between transmittance, electrical interconnection, and bottom cell degradation. Using polySi/SiO passivating contacts for Si, this degradation can be largely circumvented by tuning the polySi/SiO stacks to promote gettering of contaminants admitted into the Si bottom cell during the top cell synthesis.

Intrinsic Defects in MoS Grown by Pulsed Laser Deposition: From Monolayers to Bilayers.

Pulsed laser deposition (PLD) can be considered a powerful method for the growth of two-dimensional (2D) transition-metal dichalcogenides (TMDs) into van der Waals heterostructures. However, despite significant progress, the defects in 2D TMDs grown by PLD remain largely unknown and yet to be explored. Here, we combine atomic resolution images and first-principles calculations to reveal the atomic structure of defects, grains, and grain boundaries in mono- and bilayer MoS grown by PLD.

Spin-coated [Formula: see text] solar cells: A study on the transformation from ink to film.

In this paper, we study the DMSO/thiourea/chloride salt system for synthesis of pure-sulfide [Formula: see text] (CZTS) thin-film solar cells under ambient conditions. We map out the ink constituents and determine the effect of mixing time and filtering. The thermal behavior of the ink is analyzed, and we find that more than 90% of the solvent has evaporated at [Formula: see text].

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS.

Energy band alignment at the heterointerface between CdS and kesterite CuZnSnS (CZTS) and its alloys plays a crucial role in determining the efficiency of the solar cells. Whereas Ag alloying of CZTS has been shown to reduce anti-site defects in the bulk and thus rise the efficiency, the electronic properties at the interface with the CdS buffer layer have not been extensively investigated. In this work, we present a detailed study on the band alignment between n-CdS and p-CZTS upon Ag alloying by depth-profiling ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS).

Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review.

In kesterite CuZnSn(S,Se) (CZTSSe) solar cell research, an asymmetric crystallization profile is often obtained after annealing, resulting in a bilayered - or double-layered - CZTSSe absorber. So far, only segregated pieces of research exist to characterize the appearance of this double layer, its formation dynamics, and its effect on the performances of devices. In this work, we review the existing research on double-layered kesterites and evaluate the different mechanisms proposed.

Characterization of CuZnSnS Particles Obtained by the Hot-Injection Method.

In the last decade, CuZnSnS (CZTS) has been a promising earth-abundant, nontoxic candidate material for absorption layers within thin-film solar cells. One major issue preventing this type of solar cells from achieving competitive efficiency is impurity phases and structural defects in the bulk of the absorber; as a four-element compound, the formation of CZTS is highly sensitive to synthesis conditions. The impurity phases and defects differ by the fabrication method, and thus experimental characterization is vital for the successful development of CZTS photovoltaics.

Liquid phase assisted grain growth in CuZnSnS nanoparticle thin films by alkali element incorporation.

The effect of adding LiCl, NaCl, and KCl to CuZnSnS (CZTS) nanoparticle thin-film samples annealed in a nitrogen and sulfur atmosphere is reported. We demonstrate that the organic ligand-free nanoparticles previously developed can be used to produce an absorber layer of high quality. The films were Zn-rich and Cu-poor, and no secondary phases except ZnS could be detected within the detection limit of the characterization tools used.

Interfacial structure and photocatalytic activity of magnetron sputtered TiO₂ on conducting metal substrates.

The photocatalytic behavior of magnetron sputtered anatase TiO2 coatings on copper, nickel, and gold was investigated with the aim of understanding the effect of the metallic substrate and coating-substrate interface structure. Stoichiometry and nanoscale structure of the coating were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscope, and scanning and transmission electron microscopy. Photocatalytic behavior of the coating was explored by using optical spectrophotometry and electrochemical methods via photovoltage, photocurrent, and scanning kelvin probe microscopy measurements.

Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens.

A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions.

Pulsed radiofrequency glow discharge time-of-flight mass spectrometry for molecular depth profiling of polymer-based films.

We demonstrate the potential of an innovative technique, pulsed radiofrequency glow discharge time-of-flight mass spectrometry, for the molecular depth profiling of polymer materials. The technique benefits from the presence, in the afterglow of the pulsed glow discharge, of fragment ions that can be related to the structures of the polymers under study. Thin films of different polymers (PMMA, PET, PAMS, PS) were successfully profiled with retention of molecular information along the profile.