O2(a1Δg) production and oxygen diffusion in C60 films

Long-Lifetime and Asymmetric Singlet Oxygen Photoluminescence from Aqueous Fullerene Suspensions

“…It must be noted that such long lifetimes for O 2 (a 1 Δ) luminescence have never been previously reported in aqueous solutions and suspensions, but have been observed in solid C 60 crystals. For example, the O 2 (a 1 Δ) lifetime within C 60 crystals measured by Howells et al is ∼1.5 ms at 280 K, while the value obtained by Nissen et al at 300 K is about 2–3 ms, both by and large in agreement with our results in nC 60 suspensions. Interestingly, recent reports have already shown that the nC 60 aggregates in various aqueous suspensions are heterogeneous in size and shape, and crystalline in structure. − ,, Therefore, we can presume that the nC 60 aggregates in our ultrasonic suspensions should also be crystalline in structure and the O 2 (a 1 Δ) observed in our nC 60 suspensions exactly comes from the interior of C 60 crystals, thus leading to its lifetime up to 2–3 ms.…”

A jet-type singlet oxygen generator based on porous fullerene-containing structures

“…The estimates show that the singlet oxygen yield of 1.6 × 10 18 molecules/cm 2 s -1 with quantum effi ciency of more than 30% can be achieved by providing of a flow of oxygen through the porous structure of the substrate to the fullerene surface irradiated by an opti cal pump source with a power density of 750 mW/cm 2 . Even higher efficiency of the singlet oxygen produc tion on a solid state fullerene surface was reported in [4]; however, the authors noted a difficulty with the release of singlet oxygen produced in the fullerene film into the gas phase, because only the diffusion mecha nism of singlet oxygen desorption was considered. In our case, the problem was easily solved by using the gas flow through the porous structure of the fullerene coating.…”

“…The total yield of oxygen from the membrane was 5 × 10 16 cm -2 s -1 . The single oxygen content in the flow was 12%, whereas the content required for operation of the oxy gen-iodine laser is at least 15% [3][4][5][6]. The power of the luminescence emitted from the entire membrane surface was 1 W. Hence, the light, or physical, effi ciency was 3.5% with a quantum yield of 10%.…”

“…We refer the reader to a comprehensive review of the field [1], as well as a number of later studies and patents [2][3][4][5][6][7][8][9]. Shortly after the discovery of fullerene, several works reported its use as a photosensibilizer for singlet oxygen gener ation.…”

Dielectric properties of orientationally ordered/disorderedC60(111) films

“…12,5 Since it is difficult to avoid exposure to oxygen, and because oxygen molecules can strongly influence the dc conductivity of solid C 60 crystals ͑by several orders of magnitude͒, 10,13 issues in connection with oxygen intercalation have received considerable attention in the literature. [12][13][14][15][16][17][18][19][20][21][22][23] Most significantly, NMR studies 19 have shown that oxygen molecules reside in the octahedral vacancies of C 60 lattice, and since other lattice vacancies have smaller volumes, these vacancies remain unoccupied. 20 NMR studies have also shown that intercalation with oxygen is a kinetically limited process, 19 indicating that the distribution of the occupied sites remain far from equilibrium.…”