Growth and properties of pure C60 single crystals from vapor

Li, J.; Komiya, Satoshi; Tamura, T.; Nagasaki, Chikage; Kihara, Junji; Kishio, K.; Kitazawa, K.

doi:10.1016/0921-4534(92)90092-q

Cited by 56 publications

(7 citation statements)

References 11 publications

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“…In general, thermally deposited fullerene films are reported to be nearly amorphous, − whereas spin-coated fullerene films are reported to possess high crystallinity. − We used grazing-incidence X-ray diffraction (GIXRD) spectroscopy to analyze the thermally evaporated C 60 films and the spin-coated C 60 films (Figure S8). Figure a shows that the spectra of the thermally deposited C 60 films do not display any peaks, but those of the spin-coated C 60 films display the (111) peak at 10° and the (220) peak at 18° . This was also confirmed by the transmission electron microscopy (TEM) images.…”

Section: Resultsmentioning

confidence: 53%

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes

Lin

Jeon

Xiang

et al. 2018

ACS Appl. Mater. Interfaces

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Fullerenes have attracted considerable interest as an electron-transporting layer in perovskite solar cells. Fullerene-based perovskite solar cells produce no hysteresis and do not require high-temperature annealing. However, high power conversion efficiency has been only achieved when the fullerene layer is thermally evaporated, which is an expensive process. In this work, the limitations of a solution-processed fullerene layer have been identified as high crystallinity and the presence of remnant solvents, in contrast to a thermally deposited C60 film, which has low crystallinity and no remaining solvents. As a solution to these problems, a mixed C60 and C70 solution-processed film, which exhibits low crystallinity, is proposed as an electron-transporting layer. The mixed-fullerene-based devices produce power conversion efficiencies as high as that of the thermally evaporated C60-based device (16.7%) owing to improved fill factor and open-circuit voltage. In addition, by vacuum-drying the mixed fullerene film, the power conversion efficiency of the solution-processed perovskite solar cells is further improved to 18.0%. This improvement originates from the enhanced transmittance and charge transport by removing the solvent effect. This simple and low-cost method can be easily used in any type of solar cells with fullerene as the electron-transporting layer.

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Section: Resultsmentioning

confidence: 53%

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes

Lin

Jeon

Xiang

et al. 2018

ACS Appl. Mater. Interfaces

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“…The initial value of the Vickers microhardness without illumination was 18 kgf/mm 2 , which corresponds to that of intrinsic C 60 crystals at room temperature (ϳ298 K͒ in the dark. 9,[12][13][14] The maximum value of the hardness was 37 kgf/mm 2 , which is about twice as much as the intrinsic hardness without illumination. These results indicate that the hardness of C 60 crystals is very sensitive to light.…”

Section: A Photo-illumination Hardeningmentioning

confidence: 99%

Photo-illumination hardening of C60 crystals

Tachibana

Sakuma

Kojima

1997

Journal of Applied Physics

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The effect of light on the hardness of C 60 crystals was investigated. The hardness increased after the crystals were illuminated with white light. Such a photo-illumination hardening was effective in a temperature range of 298-380 K. The photopolymerized C 60 molecules near the crystal surface were responsible for the hardening. The anomalous temperature dependence of the hardness at temperatures higher than 300 K, which we previously have observed, is explained as due to the photo-illumination hardening.

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“…The Vickers hardness value of pure C 60 crystals is reported to be around 20 HV [11,12], which is equal to that of pure gold surfaces. Table 2 shows the Vickers hardness of pure C 60 and impurity-doped C 60 films.…”

Section: Resultsmentioning

confidence: 93%

Characteristics of multivalent impurity doped C60 films grown by MBE

Nishinaga

Aihara

Kawaharazuka

et al. 2007

Journal of Crystal Growth

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Metal-doped C 60 films (aluminum, gallium and germanium) are grown on GaAs and quartz glass substrates by solid source molecular beam epitaxy. Mechanical and optical properties of the films are investigated by Vickers hardness test and photoluminescence (PL) measurement. Vickers hardness values of all the impurity-doped C 60 films are considerably enhanced. PL peaks of the electron transition between the highest occupied molecular orbital and the lowest unoccupied molecular orbital states of C 60 molecules are confirmed in Al-doped and Ga-doped C 60 films, but not in Ge-doped C 60 films. Optimized bonding structures of these impurity atoms to C 60 molecules are determined by using ab initio calculations. Stable covalent bonds between impurities and C 60 molecules are verified to be formed. The impurity atoms may act as bridges between C 60 molecules. The distortion of C 60 cages due to the bonding with metals is confirmed. In the Al-and Ga-doped C 60 films, this distortion probably makes the dipole forbidden transition relieved. The binding energies are found to be related to the experimentally determined Vickers hardness. r

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Growth and properties of pure C60 single crystals from vapor

Cited by 56 publications

References 11 publications

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes

Photo-illumination hardening of C60 crystals

Characteristics of multivalent impurity doped C60 films grown by MBE

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Growth and properties of pure C60 single crystals from vapor

Cited by 56 publications

References 11 publications

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C60/C70 Mixed Fullerenes

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C60/C70 Mixed Fullerenes

Photo-illumination hardening of C60 crystals

Characteristics of multivalent impurity doped C60 films grown by MBE

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Product

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Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes

Achieving High Efficiency in Solution-Processed Perovskite Solar Cells Using C₆₀/C₇₀ Mixed Fullerenes