The synthesis of long and thin Ag nanowires is important to achieve high performance transparent conductive films. We report a one-step route to synthesizing Ag nanowires with an average diameter of ∼25 nm and an aspect ratio larger than 1000 by utilizing a mixture of poly(vinylpyrrolidone) with different molecular weights as the capping agent in a polyol reduction reaction.

Silver nanowire transparent conductive films are one of the most promising alternatives to indium tin oxide films in the application of touch panels. Low haze and high uniformity are two essential factors for high-end applications of the films. However, the reported haze and uniformity of such kinds of films are still lagging much behind what is required for real-world applications. Herein, the fabrication of silver nanowire transparent conductive films with an ultra-low haze and ultra-high uniformity is reported. DLVO theory is applied to purify silver nanowires and the corresponding ink of the nanowires with narrower size dispersion and less nanoparticle contaminants is formulated for film coating. The fabricated films exhibit a low haze of 0.8% and good uniformity with the non-uniformity factor of 5.0% (defined as the standard deviation of the sheet resistance) at a transmittance of 91.7% (99.4% for the silver nanowire network only without a substrate) and a sheet resistance of 71.2 Ω square⁻¹. The outperforming films are utilized to construct touch-panels with excellent performance for fluent writing. The findings in this work will pave the way for real-world applications of silver nanowire transparent conductive films replacing those of indium tin oxide.

The synthesis of very thin Ag nanowires in the presence of Br⁻ ions is typically accompanied by the generation of a huge amount of Ag nanoparticles. Herein, we report a method to suppress the homogeneous nucleation of Ag seeds in the growth process of Ag nanowires, hence dramatically enhancing the purity of the synthesized very thin Ag nanowires. These Ag nanowires having a diameter approaching 20 nm and an aspect ratio larger than 1500, as well as an ultra-low particle impurity level of 5.5% are directly used after simple water washing to form transparent conductive films with much improved optical and electrical properties, which have great potential for high-end applications including touch panels.

Monodispersed AgBiS₂ quantum dots of high phase purity with an average diameter of 8.5 ± 1.2 nm have been synthesized for the first time by a hot-injection method. The optical band gap of the well-dispersed quantum dots is ∼2.67 eV, indicating a strong quantum confinement. The quantum dot pellet shows a large dielectric constant of the order of 10⁵. Independent measurements demonstrate that the large grain boundary resistance and capacitance contribute to the giant dielectric constant. Monodispersed AgBiS₂ quantum dots may find significant implications in high-k applications.

Very thin silver nanowires are ideal building blocks for fabricating high-performance transparent conductive films simultaneously with low sheet resistance, high visible light transparency, a small haze factor, and high uniformity. Synthesis of very thin silver nanowires with an average diameter close to 20 nm has been realized by a polyol reduction method in the presence of Br⁻ and Cl⁻ ions. However, nanoparticles contained in the product are detrimental to the overall performance of transparent conductive films, and there have been no methods to purify very thin silver nanowires which are both cost-effective and environmentally friendly. In this work, we report on the Ostwald ripening-driven coarsening of the nanoparticles, followed by sedimentation and brief filtration to separate the particles from very thin silver nanowires. This method is free from the involvement of toxic acetone and could produce very thin silver nanowires with high purity. It is convenient and suitable for large-scale implementation. The films prepared with the purified very thin silver nanowires exhibit a low sheet resistance of 71.3 ± 2.9 Ω □⁻¹ at a high transmittance of 91.7%, a low haze of 1.0%, and a small standard deviation of the sheet resistance of 4.0%, without further treatment processes. The findings in this work will pave the way for the real-world application of very thin silver nanowires towards high-performance transparent conductive films and flexible electronics.

Ternary semiconductor nanocrystals from the I–V–VI family have potential applications in many fields. In this work, we report on the synthesis of well-dispersed Cu₃SbS₃ nanocrystals with an average diameter of 23.0 ± 4.9 nm. The as-synthesized Cu₃SbS₃ nanocrystals are of high phase purity and stable against phase separation when heating up to 400 °C in an inert atmosphere or left at room atmosphere for 80 days. The optical band gap of the nanocrystals is calculated as ~1.87 eV. The nanocrystal film shows strong near infrared absorption and is sensitive towards detecting trace amounts of Rhodamine 6G by using surface-enhanced Raman scattering. These observations imply the huge potentials of Cu₃SbS₃ nanocrystals in photothermal, photovoltaic, and sensing applications.