Work

Nickel Oxide Films with Superior Electrochromic Performance Reinforced by Graphene Quantum Dots

Year: 2026

Type: article

Abstract: Nickel oxide (NiO) is considered as an ideal counter electrode to build complementary electrochromic devices with tungsten oxide (WO 3 ) due to charge balance, and complementary color modulation. However, currently reported NiO films exhibit poor electrochromic properties in LiClO 4 /PC electrolytes due to poor conductivity and Li + trapping. Here, a novel strategy is exploited to enhance the electrochromic properties of NiO films in LiClO 4 /PC based on graphene quantum dots (GQDs). GQDs with uniform particle size and rich surface functional groups are prepared by cracking carbon nanotubes with HNO 3 , and then GQDs/NiO composite films are synthesized through chemical bath deposition. The strong interface bonding between GQDs and NiO allows for the efficient promotion of charge transfer and Li + diffusion with larger surface potential difference, and alleviate stress produced during the electrochromic reaction. GQDs‐2/NiO demonstrate outstanding electrochromic performance in LiClO 4 /PC with wider optical modulation (ΔT of 56%), faster switching speed (τ c /τ b = 3.7/2.4 s), and better cycle stability (5000 cycles) than that of pure NiO. Besides, the electrochromic devices assembled by GQDs‐2/NiO display excellent electrochromic performances. This study provides innovative guidance for the preparation of NiO films with excellent electrochromic properties in LiClO 4 /PC electrolytes, and pioneers new route for expanding the optoelectronic applications of GQDs.

Source: Advanced Optical Materials

DOI: 10.1002/adom.202503204