Verification of Carrier Concentration‐Dependent Behavior in Water‐Infiltration‐Induced Electricity Generation by Ionovoltaic Effect

Abstract

Water‐infiltration‐induced power generation has the renewable characteristic of generating electrical energy from ambient water. Importantly, it is found that the carrier concentration in semiconductor constituting the energy generator seriously affect the electricity generation. Nevertheless, few studies are conducted on the influence of semiconductor carrier concentration, a crucial factor on electricity generation. Due to this, understanding of the energy harvesting mechanism is still insufficient. Herein, the semiconductor carrier concentration‐dependent behavior in water‐infiltration‐induced electricity generation and the energy harvesting mechanism by ionovoltaic effect are comprehensively verified. A clue to enhance the electric power generation efficiency is also proposed. When 20 µL of water (NaCl, 0.1 m) infiltrates into a porous CuO nanowires film (PCNF), electric power of ≈0.5 V and ≈1 µA are produced for 25 min. Moreover, the PCNF shows good practicability by generating electricity using various ambient water, turning on LEDs, and being fabricated as a curved one.

Moisturized 2-dimensional halide perovskite generates a power density of 30 mW cm−3

“…It was reported that the ionovoltaic effect was generated by a change in surface energy levels via ion dynamic motions. 32,33 Thus, the surface potential changes induced by the ion motions can partially contribute to the electric output. The AFM and KPFM images of the perovskite thin film under 55% RH were also measured and shown in Fig.…”

Ionovoltaics in energy harvesting and applications: A journey from early development to current state‐of‐the‐art

“…12,[22][23][24] On the contrary, the established theory of ionovoltaics and the exploration of the voltage drop effect due to the 42 resistance of semiconductor electrodes were utilized as a fundamental theory for interpreting the core driving principle of the device. 48,54,[61][62][63][64] Thus, the theoretical hypothesis that the driving force behind continuous ionovoltaic generations based on evaporation/capillary phenomena is due to the change in carrier concentration in semiconductor electrodes was experimentally verified. [65][66][67] Therefore, to increase the efficiency of ionovoltaic sustainable energy generation, it is important to design nano/2D/ porous structured materials with large surface area and functional surfaces and to identify key elements that can control water flow inside the nanoscopic structure.…”

“…For the first time, the semiconductor carrier concentration-dependent behavior in water-infiltrationinduced power generation by ionovoltaic effect was investigated. 61 A porous semiconductor based on CuO nanowires was fabricated, and its electrical properties were controlled by atmospheric pressure plasma (APP) treatment (Figure 12A). [117][118][119][120] Increasing the carrier concentration of CuO nanowires by prolonging the APP time led to an improvement in the output performance of the waterinfiltration-induced ionovoltaic device (Figure 12B,C).…”

Nanofluidic Membrane with Spent Battery Residues for Efficient Energy Generation

“…The solid–liquid coupling shows a superior technology with high flexibility and eco-friendly development. So far, water-enabled electric generation developed is based on ion diffusion, flow potential, , evaporating potential, and ionovoltaic effect, , which are affected by the water–solid interface interaction. Among them, water transmission and evaporation-induced electricity stand out because they can operate independently in a wide range of environments without requiring mechanical input. − The generator can generate sustainable electricity by the capillary action between water and solid surfaces when water passes through nano/micropores until the water completely evaporates. − …”