Self‐Crystallization of C₇₀ Cubes and Remarkable Enhancement of Photoluminescence

Abstract

Good solvent, poor solvent: A simple precipitation method enabled the spontaneous formation of homogeneous C70 cube crystals by self‐crystallization in cavities of a good solvent (mesitylene) surrounded by a poor solvent (isopropyl alcohol, IPA; see picture). The enormously increased photoluminescence (PL) intensity of the C70 cube crystals relative to that of C70 powder was mainly attributed to the high crystallinity of the cubes.

Solvated fullerenes, a new class of carbon materials suitable for high-pressure studies: A review

“…The extra Raman peaks observed in the solvate suggest van-der-Waals interactions between the C 60 molecules and the solvents, which reduces the symmetry of the C 60 molecular and renders electric-dipole transitions that were impossible with pristine C 60 due to high symmetry possible [28]. This phenomenon has also been observed in C 70 solvates [102].…”

Hierarchically Structured Fullerene C70 Cube for Sensing Volatile Aromatic Solvent Vapors

“…41 Moreover, when FC fabricated using a different solvent system (mesitylene/IPA) was treated with fresh IPA, HFC formation did not take place. 38,39 Rather, the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 9 cube-to-rod transformation led to randomly oriented masses of nanorods ( Figure S16). Similar randomly arranged nanorods were also observed upon exposure of FC to IPA vapor for longer times  72 h ( Figure S17) or when FC was treated with IPA at 60 ºC ( Figure S18).…”

“…a = 1.05 nm. 38,39 In contrast, pristine C70 has a hexagonal closed pack (HCP) structure 40 with lattice parameters ca. a = 1.08 and c = 1.74 nm.…”

“…The solid solvate structure of FC with mesitylene molecules trapped at the interstitial site of the SC lattice was confirmed by FT-IR study ( Figure S7) and is supported by thermogravimetric analysis ( Figure S8). 39 For the fabrication of HFC (Figure 1a), solid FC (0.5 mg) was added to IPA (1 mL) and gentle hand shaking was applied for 30 s, followed by storing in an incubator at 25 C for 1 h. SEM observations revealed that IPA causes structural rearrangements of the FC resulting in the formation of fullerene C70 nanorods, which protrude from the cube surface (Figure 1d, e and Figure S9). The nanorod formation process is very rapid (~ 3 min) and the diameters of the nanorods increase with time finally attaining a size of ca.…”

On the mechanochemical activation by ultrasound

“…7). 44 C 70 powder is first dissolved in mesitylene and the subsequent addition of isopropyl alcohol induces the formation of an immiscible liquidliquid interface. The resulting precipitate however contains rectangular-shaped crystals of variable size, whereas sonication prevents random nucleation and leads to shape homogeneity.…”