Thin-Film Solar Cells Based on Selenized CuSbS2 Absorber.

Copper antimony sulfide (CuSbS2) has attracted significant interest as an earth-abundant photovoltaic absorber. However, the efficiency of the current CuSbS2 photovoltaic device is too low to meet the requirement of a large-scale application. In this study, selenylation was introduced to optimize the band structure and improve the device performance. Selenized CuSbS2 [CuSbS2(Se)] films were realized using porous CuSbS2 films prepared by spray deposition with a post-treatment in Se vapor. The as-prepared CuSbS2(Se) films exhibited a compact structure. X-ray diffraction and elemental analysis confirmed the effective doping of Se into the lattice by substituting a part of S in CuSbS2. Elemental analysis revealed a gradient distribution for Se from the top surface to the deeper regions, and the substitution rate was very high (>39%). Dark J-V characteristics and AC impedance spectroscopy analysis showed that selenylation significantly reduced the carrier recombination center. As a result, the selenized CuSbS2 device exhibited a significant efficiency improvement from 0.12% to 0.90%, which is much higher than that of the simply annealed device (0.46%), indicating this technique is a promising approach to improve the performance of CuSbS2 solar cells.

Preparation of Device-Level ZnO-Covered Silver Nanowires Films and Their Applications as Sub-Electrode for Polymer Solar Cells.

Silver nanowire films are good candidates to be used as transparent conductive films that could be widely utilized in organic photoelectronic devices such as polymer solar cells. However, their application is usually limited, as they are mainly used as top electrode materials; otherwise, they would be prone to complex transferring processes. In this study, we successfully prepared device-level ZnO-covered silver nanowire (AgNWs/ZnO) films. ZnO was prepared by a spray pyrolysis method using zinc-ammonia solution at a relatively low temperature (95°C). The films showed good adhesive properties to the glass substrate, considering it withstood the process of applying polyimide tapes on the surface and tearing them off more than 100 times. It also exhibited good conductivity (∼24 Ω/sq) with high transmittance in the visible range (>80%). After a simple polish and patterning, AgNWs/ZnO showed a good performance as a sub-electrode for polymer solar cells. The PM6:Y6 devices achieved a high power conversion efficiency of 8.37% with an open-circuit voltage of 0.81 V, a short-circuit current density of 18.18 mA/cm2, and a yield of 81.25%. This indicates that the technology has a good prospect of large-scale fabrication of organic photoelectronic devices.

A Phenanthroline-Based Fluorescent Probe for Highly Selective Detection of Extreme Alkalinity (pH > 14) in Aqueous Solution.

Although numerous fluorescent probes are designed to detect the pH value in the past decades, developing fluorescent probes for extreme alkalinity (pH > 14) detection in aqueous solution is still a great challenge. In this work, we utilized 1H-imidazo[4,5-f][1, 10] phenanthroline (IP) group as the recognition group of hydroxyl ion and introduced two triethylene glycol monomethyl ether groups to improve its solubility. This IP derivative, BMIP, possessed good solubility (25 mg/mL) in water. It displayed high selectivity toward extreme alkalinity (pH > 14) over other ions and pH (from extreme acidity to pH = 14). From 3 to 6 mol/L OH-, the exact concentration of OH- could be revealed by BMIP and the whole detection process just needed a short time (≤ 10 s). Meanwhile, it exhibited good anti-interference ability and repeatability during the detection process. Through optical spectra and NMR analysis, its detection mechanism was proved to be deprotonation by hydroxyl ion and then aggregation-induced enhanced emission. Our study presents a new basic group based on which researchers can develop new fluorescent probes that can detect extreme alkalinity (pH > 14) in aqueous solution.

Copper Nanowire Dispersion through an Electrostatic Dispersion Mechanism for High-Performance Flexible Transparent Conducting Films and Optoelectronic Devices.

Highly dispersed copper nanowire (CuNW) is an essential prerequisite for its practical application in various electronic devices. At present, the dispersion of CuNW is almost realized through the steric hindrance effect of polymers. However, the high post-treatment temperature of polymers makes this dispersion mechanism impractical for many actual applications. Here, after investigating the relationship between the electrostatic dispersion force and influence factors, an electrostatic dispersion mechanism is refined by us. Under the guidance of this mechanism, high dispersion of CuNW and a record low post-treatment temperature (80 °C) are realized simultaneously. The high dispersity endows CuNW with good stability (-45.66 mV) in water-based ink, high uniformity (65.7 ± 2.5 Ω sq-1) in the prepared transparent conducting film (TCF) (23 cm × 23 cm), and industrial film preparation process, which are the issues that hinder the widespread application of CuNW-based TCF at present. The low post-treatment temperature makes the application of CuNW possible on any substrate. In addition, the charge modifier, 2-mercaptoethanol, enables CuNW to resist oxidation well. Finally, flexible optoelectronic devices employing the CuNW film as the electrode are fabricated and show efficiencies comparable to those of optoelectronic devices on indium tin oxide/glass.

Stable and Controllable Synthesis of Silver Nanowires for Transparent Conducting Film.

Silver nanowires without particles are synthesized by a solvothermal method at temperature 150 °C. Silver nanowires are prepared via a reducing agent of glycerol and a capping agent of polyvinylpyrrolidone (M w ≈ 1,300,000). Both of them can improve the purity of the as-prepared silver nanowires. With controllable shapes and sizes, silver nanowires are grown continuously up to 10-20 µm in length with 40-50 nm in diameter. To improve the yield of silver nanowires, the different concentrations of AgNO3 synthesis silver nanowires are discussed. The characterizations of the synthesized silver nanowires are analyzed by UV-visible absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM), and silver nanowires are pumped on the cellulose membrane and heated stress on the PET. Then, the cellulose membrane is dissolved by the steam of acetone to prepare flexible transparent conducting thin film, which is detected 89.9 of transmittance and 58 Ω/□. Additionally, there is a close loop connected by the thin film, a blue LED, a pair of batteries, and a number of wires, to determinate directly the film if conductive or not.