Electrochemical and photoluminescence response of laser-induced graphene/electrodeposited ZnO composites

Abstract

The inherent scalability, low production cost and mechanical flexibility of laser-induced graphene (LIG) combined with its high electrical conductivity, hierarchical porosity and large surface area are appealing characteristics for many applications. Still, other materials can be combined with LIG to provide added functionalities and enhanced performance. This work exploits the most adequate electrodeposition parameters to produce LIG/ZnO nanocomposites. Low-temperature pulsed electrodeposition allowed the conformal and controlled deposition of ZnO rods deep inside the LIG pores whilst maintaining its inherent porosity, which constitute fundamental advances regarding other methods for LIG/ZnO composite production. Compared to bare LIG, the composites more than doubled electrode capacitance up to 1.41 mF cm−2 in 1 M KCl, while maintaining long-term cycle stability, low ohmic losses and swift electron transfer. The composites also display a luminescence band peaked at the orange/red spectral region, with the main excitation maxima at ~ 3.33 eV matching the expected for the ZnO bandgap at room temperature. A pronounced sub-bandgap tail of states with an onset absorption near 3.07 eV indicates a high amount of defect states, namely surface-related defects. This work shows that these environmentally sustainable multifunctional nanocomposites are valid alternatives for supercapacitors, electrochemical/optical biosensors and photocatalytic/photoelectrochemical devices.

Magnéli-Phase Ti4O7-Doped Laser-Induced Graphene Surfaces and Filters for Pollutant Degradation and Microorganism Removal

“…In earlier studies, oxidation of LIG electrodes was seen with time; however, with LIG–Ti 4 O 7 , we have seen a stable current for a longer duration as compared to LIG at 2.5 V for 6 h (Figure S7). Additionally, charge density which is directly proportional to the CV curve area was calculated using eq , and it is a direct indicative of the electrochemical active surface area and hence the electrochemical activity of the materials. , C = ∫ I .25em normald V v .25em ( μ C · c m 2 ) …”

“…Additionally, charge density which is directly proportional to the CV curve area was calculated using eq 1, and it is a direct indicative of the electrochemical active surface area and hence the electrochemical activity of the materials. 59,60…”

ZnO Transducers for Photoluminescence-Based Biosensors: A Review

“…Indeed, the synthesis method plays a vital role in the defect incorporation, and thus, in the optical active defects present in the structures [80,99,100]. Moreover, even when the same method is applied, the grown conditions (e.g., temperature, atmosphere) affect the final properties of the crystals, like size and morphology, which in turn also influence the PL outcome.…”

Compacted Laser‐Induced Graphene with Bamboo‐Like Carbon Nanotubes for Transformable Capacitive Energy Storage Electrodes

“…Nevertheless, it is still unclear what potential effects can be produced by the use of the neglected space in a porous LIG framework. To overcome these limitations, porous graphene-based hybrid composites including metal nanorode, [32] conducting polymer nanowire, [33] and carbon nanotube [34,35] have allowed for further improvements in the energy storage device.…”