Floating Catalyst Chemical Vapor Deposition Patterning Nitrogen‐Doped Single‐Walled Carbon Nanotubes for Shape Tailorable and Flexible Micro‐Supercapacitors

Abstract

Micro-supercapacitors (MSCs) as high-power density energy storage units are designed to meet the booming development of flexible electronics, requiring simple and fast fabrication technology. Herein, a fast and direct solvent-free patterning method is reported to fabricate shape-tailorable and flexible MSCs by floating catalyst chemical vapor deposition (FCCVD). The nitrogen-doped single-walled carbon nanotubes (N-SWCNTs) are directly deposited on a patterned filter by FCCVD with designable patterns and facilely dry-transferred on versatile substrates. The obtained MSCs deliver an excellent areal capacitance of 3.6 mF cm −2 and volumetric capacitance of 98.6 F cm −3 at a scan rate of 5 mV s −1 along with excellent long-term cycle stability over 125 000 circles. Furthermore, the MSCs show good performance uniformity, which can be readily integrated via connection in parallel or series to deliver a stable high voltage (4 V with five serially connected devices) and large capacitance (5.1 mF with five parallel devices) at a scan rate of 100 mV s −1 , enabling powering the light emitting displays. Therefore, this method blazes the trail of directly preparing flexible, shape-customizable, and high-performance MSCs.

Direct synthesis of nitrogen-doped narrow-diameter carbon nanotubes through floating-catalyst chemical vapor deposition with high hydrogen flow rate

“…2(b)], which correspond to pyridinic-N (denoted as N P , hereafter) at 398.1-398.6 eV, graphitic-N (N G ) at 400.8-401.4 eV, and pyridine-N-oxide (N O ) at 402.5 eV, respectively. 10,29,33,34) Moreover, the intensity of N P peaks decreases with increasing the synthesis temperature, thus the N G peak becomes a dominant C-N component at a high temperature above 1000 °C. Figure 2(c) shows a relation between the N content of N-CNTs and synthesis temperature.…”

“…ubstitutional doping of nitrogen (N) atoms plays an essential role in tuning the electronic properties of carbon nanotubes (CNTs), [1][2][3] offering promising applications for gas sensors, 4) field emission devices, 5,6) transistors, 7) and energy storage devices. [8][9][10] The unique ability of N-doped CNTs (N-CNTs) ranging from electronic devices to enhancing electrochemical activity originates from three possible C-N bonding configurations: graphitic-N (a three-coordinated N atom within the sp 2 -hybridized network of CNTs; n-type doping), pyridinic-N (a two-coordinated N atom with a lone-pair state; p-type doping), and pyrrolic-N (an N atom incorporated in the pentagon ring of carbon). [1][2][3] Wiggins-Camacho and Stevenson showed experimentally that the density of states at the Fermi level of N-CNTs increases with increasing the N-doping amount (<7.4 at%).…”

“…Among the various methods to synthesize N-CNTs including an arc-discharge method, 25) a chemical vapor deposition (CVD) method with catalyst supports, 17,26,27) and posttreatments of CNTs, 28,29) a floating-catalyst CVD (FCCVD) method provides a rich potential for the continuous and onestep production of N-SWCNTs 10,19) with facile controllability of the nanotube growth. 30) A typical FCCVD process involves the thermal decomposition of a catalyst source (e.g., metallocenes) and carbon/nitrogen sources which are injected into a reactor through a carrier gas, subsequently growing nanotubes in the gas phase.…”

“…30) A typical FCCVD process involves the thermal decomposition of a catalyst source (e.g., metallocenes) and carbon/nitrogen sources which are injected into a reactor through a carrier gas, subsequently growing nanotubes in the gas phase. A variety of N-containing hydrocarbons has been used as nitrogen sources (e.g., pyridine, 27) acetonitrile, 10) melamine, 19) and caffeine 20) ). Regarding the efficient synthesis of N-SWCNTs through an FCCVD method, a key process is to control the pyrolysis of N-containing hydrocarbons concurrently with the growth of CNTs.…”

Improved Performance of AlGaInP Red Micro Light-Emitting Diodes by Sidewall Treatments of Citric Acid

“…Nitric acid is utilized for etching sapphire or LEDs to create microstructures, potentially associated with the need for specific surface structures in the process [20][21]. Overall, the application of these acidic solutions encompasses multiple processing steps, including oxide removal, surface roughening, and microstructure generation [22][23][24]. Compared with large-scale LEDs, miniature LEDs have a high surface area-to-volume ratio.…”