Electrochromic Properties of Perovskite NdNiO₃ Thin Films for Smart Windows

Abstract

Semiconductors with electrically tunable band gaps are of great interest in controlling transparency to electromagnetic radiation. Thin films of perovskite nickelate NdNiO3 (NNO), a class of correlated oxides, were deposited on single-crystal (LaAlO3 (LAO)) and polycrystalline (fluorine-doped tin oxide-coated glass (FTO)) substrates by magnetron sputtering, chemical solution deposition (CSD), and atomic layer deposition (ALD). Their electrochromic behaviors were investigated using a three-electrode setup in basic (KOH solution, pH = 12) electrolyte. During bleaching/coloration process, the proton intercalation/deintercalation and simultaneous electron compensation in the NNO lattice under electrical bias led to crossover of the material between the pristine-conducting phase (Ni3+) and the strongly correlated insulating phase (Ni2+), which serves as the working principle for electrochromic (tunable opacity in the visible range) behavior. Cyclic voltammetry (CV) scans demonstrate that NNO films are electrochemically stable in basic solutions for all three film deposition methods explored here. CV scans at varying rates enabled the extraction of diffusion coefficient of protons in thin film NNO, which is ∼10–7 cm2 s–1 among all films studied. Large light transmittance modulation by bleaching and coloration was observed on films grown on both LAO and FTO substrates, suggesting its potential as an electrochromic material candidate for smart windows and optical shutter applications. Porous NNO films obtained by chemical solution deposition tend to demonstrate stronger electrochromic activity than dense films grown by sputtering or ALD.

Large Negative Photoresistivity in Amorphous NdNiO3 Film

“…Even visually, the epitaxial film is much darker than the amorphous one, proving a twice as high absorption factor (see Figure 1e and Ref. [14]). Both film-substrate stacks absorb the light of lower wavelengths better; however, this dependence is not so pronounced for the epitaxial films.…”

Emerging Electrochromic Materials and Devices for Future Displays

“…A side-chain modification with polar amide functional groups on EC polymers was introduced to achieve redox switching in aqueous electrolytes . A layer-by-layer assembly of polyaniline with nanocages was achieved. , In addition, EC thin films of perovskite nickelate NdNiO 3 (NNO) were also prepared, which further increased the selection range of EC materials …”

Electrochromic Behavior Originating from the W6+/W5+ Redox in Aurivillius-type Tungsten-Based Layered Perovskites

“…Recently, it was reported that perovskite structural NdNiO 3 exhibits significant coloring and bleaching behavior when a low voltage between −0.7 to 1 V is applied. 12 Therefore, the structure of perovskites is an appropriate structural type for EC materials based on multiple oxides. However, the closed packing structure leads to a confined space for the intercalation cations.…”

“…Recently, multiple oxide materials have been applied in EC materials by utilizing diverse elements, e.g. , Bi 2 WO 6 and NdNiO 3 are known to show specific EC abilities. , In addition, many multiple oxides have high chemical and physical stability because of their rigid structure due to their three-dimensional frameworks. However, such multiple oxide-based EC materials are still an exploratory research step; therefore, the systematic study of multiple oxide-based EC materials will play an important role in the future study of EC materials.…”

“…Perovskite materials (described as AB O 3 ) have a rigid framework due to the closed packing structure and are typical multiple oxides. Recently, it was reported that perovskite structural NdNiO 3 exhibits significant coloring and bleaching behavior when a low voltage between −0.7 to 1 V is applied . Therefore, the structure of perovskites is an appropriate structural type for EC materials based on multiple oxides.…”