Evaporation-induced electricity generation, harnessing natural vaporization of water, is spotlighted as a promising energy conversion system with showing off remarkable characteristics such as continuous generation without artificial water motions. However, the vague origin and mechanism of this phenomenon are obstacles for practical application. Herein, the origin of the evaporation-induced electricity generation was verified in terms of the "ionovoltaic" effect, ionic motion-induced charge carrier flows, through a resistance-controllable metal oxide platform. The device, composed of solvothermal-grown zinc oxide, showed output signals of ∼0.4 V and ∼20 nA. This study improves an understanding of the evaporative ionovoltaic mechanism and secures applicability to various materials for future energy conversion devices.

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We verified the origin of water-infiltration-induced electricity generation by ionovoltaic effect, specifically, ion-surface interaction induced potential asymmetry in porous structures. When 20 μl of water (NaCl, 0.1 M) infiltrates into...

The change in electrical properties of electrodes by adsorption or desorption at interfaces is a well‐known phenomenon required for signal production in electrically transduced sensing technologies. Furthermore, in terms of electrolyte–insulator–semiconductor (EIS) structure, several studies of energy conversion techniques focused on ion‐adsorption at the solid–liquid interface have suggested that the electric signal is generated by ionovoltaic phenomena. However, finding substantial clues for the ion‐adsorption phenomena in the EIS structure is still a difficult task because direct evidence for carrier accumulation in semiconductors by Coulomb interactions is insufficient. Here, a sophisticated Hall measurement system is demonstrated to quantitatively analyze accumulated electron density‐change inside the semiconductor depending on the ion‐adsorption at the solid–liquid interface. Also, an enhanced EIS‐structured device is designed in an aqueous‐soaked system that works with the ionovoltaic principle to monitor the ion‐dynamics in liquid electrolyte media, interestingly confirming ion‐concentration dependence and ion‐specificity by generated peak voltages. This newly introduced peculiar method contributes to an in‐depth understanding of the ionovoltaic phenomena in terms of carrier actions in the semiconductors and ionic behaviors in the aqueous‐bulk phases, providing informative analysis about interfacial adsorptions that can expand the scope of ion‐sensing platforms.

The ginsenosides Rh2 and Rg3 induce tumor cell apoptosis, inhibit tumor cell proliferation, and restrain tumor invasion and metastasis. Despite Rh2 and Rg3 having versatile pharmacological activities, contents of them in natural ginseng are extremely low. To produce ginsenosides Rh2 and Rg3, the saponin-producing capacity of endophytic bacteria isolated from Panax ginseng was investigated. In this work, 81 endophytic bacteria isolates were taken from ginseng roots by tissue separation methods. Among them, strain PDA-2 showed the highest capacity to produce the rare ginsenosides; the concentrations of rare ginsenosides Rg3 and Rh2 reached 62.20 and 18.60 mg/L, respectively. On the basis of phylogenetic analysis, it was found that strain PDA-2 belongs to the genus Agrobacterium and was very close to Agrobacterium rhizogenes.