Photomagnetic Carbon Nanotubes at Ambient Conditions

Abstract

KEYWORDSbis(2,2-bipyridine)-5-amino-1,10-phenanthroline ruthenium(II), carbon nanotube, diazotization, photoinduced charge transfer, photomagnetism ABSTRACT Bis(2,2-bipyridine)-5-amino-1,10-phenanthroline ruthenium(II) (Ru(bpy) 2 (phen-NH 2 ) 2+ ), an MLCT complex, has a long-lived triplet state in water (λ ex :473 nm; λ em : 620 nm; τ = 615 ns; Φ = 1 relative to that of Ru(bpy) 3 2+ ) and a structure analogous to Ru(bpy) 3 2+ . When Ru(bpy) 2 (phen-NH 2 ) 2+ was subjected to diazotization in the presence of carbon nanotubes (CNTs), it formed nanodots on the CNTs, rendering the resulting tubes (Ru@CNT) capable of transducing photo stimuli (473 nm) into electricity and magnetism at ambient conditions. The increased functionality was highly reproducible, as evidenced by conductive-mode AFM, vibrating sample magnetometry (VSM), and AC susceptibility analysis. The local magnetism probing of the Ru@CNT with magnetic-mode AFM techniques (MFM) indicated that the magnetism originated from the unpaired electrons formed on the photoexcited nanodots. The resulting phase shift behaved as a function of the luminous power and the voltage (V b ) of the electrical bias applied to the Ru@CNT. The V b dependence deviated from the expected quadratic correlation, confirming that the formation of the photoinduced charge separation state at the nanodots is responsible for the photomagnetism. The Ru@CNT tubes showed mobility toward external magnets (65 Gauss) when floating on water and under 473-nm illumination.The Ru@CNT thus appears to be a multifunctional material that might be useful in spintronics.

Fabrication of Photomagnetic Carbon Surfaces via Redox Assembly

“…We consider this an indication that the ruthenium compound is mainly adsorbed on the preadsorbed APBA instead of the host, which supports the mechanism proposed in Scheme 1. The Ru|APBA|CNT tube exhibits photomagnetism towards external magnets at room temperature as floating on water, similar to the tubes modified with Ru(bpy) 2 (phen-NH 2 ) 2+ [5]. The average mobility measured for the photo-illuminated Ru|APBA|CNTs ( ex : 473 nm; 27 mW) on water was 0.3 mm/min (65 Gauss).…”

“…The bare CNTs remained unmoved under similar conditions. The CNT tubes shown in Figure 6 were also investigated for their magnetic properties by the magnetic-mode AFM (MFM) [5,22]. As shown in Figure 8, the oscillation of the MFM tip changes negligibly (curves (A) and (B)) as the tip is set 4 nm atop APBA|CNT at spots (A) and (B), regardless of lights ( : 473 nm, 26 mW) on (L) and off (D).…”

“…Photosensitive nanostructures have great potential for use in a wide variety of applications, including manipulating the physiology of DNA [1], enhancing light harvesting [2], and integrating photonanoelectronics [3] and photospintronics [4]. We have recently demonstrated that ordinary multiwalled carbon nanotubes (CNTs) develop photomagnetic and photoconductive characteristics after being modified with Ru(bpy) 2 (phen-NH 2 ) 2+ (phen-NH 2 = 5-amino-1,10phenanthroline) through diazotization/denitrogenation processes [5]. Further research in this area has shown that many other ruthenium complexes, such as Ru(bpy) 2 (phendione) 2+ , are also effective alternatives to Ru(bpy) 2 (phen-NH 2 ) 2+ , and that boronic acids, including APBA, also can serve as surface adhesives [6].…”

Trident Technology Usage in Query Search time by using Cache Memory

“…Veracity explains about value and quality of data that is stored. North American Disease Spread Model it was developed with broad international carries to help policy evolution and disease incursions [4] .…”

Multiobjective optimal placement of active tendons to control irregular multistory buildings with soil–structure interaction

“…Mohebkhah and Farahani showed that by considering the effects of SSI in direct displacement‐based design of steel eccentrically braced frames, the base shear decreases, which may result in an economical design of such frames. Some research was carried out about the SSI effect on the vibration control effectiveness of an irregular building subjected to earthquake excitations . In such model, there is a large torsion around z direction, simultaneously with the lateral displacement in both x and y directions.…”