Studies of the microhardness and dislocation mobility in C60 crystals under oxidizing conditions

PHOTOINDUCED HARDENING AND REDUCTION OF DISLOCATION MOBILITY IN C60SINGLE CRYSTALS: THE WAVELENGTH DEPENDENCE

“…The aim of the present work was to investigate the wavelength dependence of phototransformation of C 60 single crystals in air using indentation hardness and dislocation mobility methods. The microindentation as a structure and depth sensitive test has been successfully used earlier in studies of the light-, atmosphere-, pressure and temperature-induced effects in fullerite (4,5,(7)(8)(9)(10)(11)(12). Investigations of the dislocation zone around indents can provide important information about photoinduced processes in the subsurface layer (7,11,13).…”

Temperature and photopolymerization effects in microhardness of C70 crystals

“…In addition, the hardness of C 60 crystals is affected by an illumination of light. [4][5][6][7] The light effect is a so-called photoillumination hardening. 4,5 The characteristics of the hardening are as follows.…”

Polymerization and Damage of C60 Single Crystals under Low Fluency Laser Irradiation

“…However, an intriguing problem is the behaviour of photopolymerization at its saturation stage. According to the recent Raman [6], microhardness [7] and atomic force microscopy (AFM) studies [8], a more complicated structure of C 60 photopolymer is supposed to arise at this stage. Another structural change is known to appear in fullerite under light irradiation and oxygen exposure.…”

“…The phototransformation of fullerite single crystals and films is observed also in air [7,[9][10][11]. However, contradictory results are reported on possible mechanisms of it.…”

“…However, contradictory results are reported on possible mechanisms of it. The photopolymerization via cycloaddition reaction [9] or photochemical transformation in oxygenated fullerite [5,7,10] are considered as main mechanisms of the phototransformation and hardening of fullerite. However, behaviour of phototransformation of C 60 single crystals in air is not understood in detail.…”