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The effective control of the sample concentration within droplets is essential in a broad range of assays in chemistry and biochemistry. Here we provide an electrical method for producing batches of aqueous droplets with various chemical concentrations by exploiting fixed-potential induced-charge electroosmosis (ICEO) flow around a bipolar electrode. By applying an AC electric signal to the bipolar electrode and changing the zeta potential on it, the bipolar electrode acts as a gate electrode for generating asymmetric ICEO flow. The ICEO flow induced transverse vortexes interact with two parallel laminar streams with different chemical compositions. Controlled mixing of the aqueous solutions can be achieved by adjusting the shape and size of the asymmetric vortexes

A novel inverse photoconductivity horizon in perovskite photo-memristor applications with various iodine concentrations, electrodes, and modified layers.

Perovskite solar cells (PSCs) have become an impressive research focus due to their unique properties, where their interface transport layers are important for an enhancement in efficiency and stability. In this study, we demonstrate that a lithium (Li) and cobalt (Co) co-doped NiOx hole transport layer can greatly enhance the device performance of inverted planar heterojunction PSCs. Compared to the pristine NiOx films and Li doped NiOx HTLs, co-doping with a certain amount of Li and Co further increased the electrical conductivity and hole mobility of the NiOx film. Consequently, the power conversion efficiency (PCE) of the PSCs greatly improved from 17.4% to 20.1% when they were co-doped with 10% Li and 5% Co. Moreover, the short-circuit current density (Jsc) increased from 22.7 mA cm−2 to 23.8 mA cm−2, the open-circuit voltage (Voc) was enhanced from 1.05 V to 1.09 V, and the fill factor (FF) was enhanced from 0.73 to 0.78 for the PSCs. These results demonstrate that the co-doping of Li and Co can be an effective strategy improving the performance of PSCs.