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固体C60/PMMA的激发态吸收光限幅研究 总被引:1,自引:1,他引:0
应用五能级模型计算了C60/PMMA的激发态吸收光限幅特性;采用调Q倍频Nd:YAG脉冲激光测量了C60/PMMA的激发态吸收光限幅效应。理论和实验结果基本符合。 相似文献
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C60/PMMA复合材料的反饱和吸收与光限幅特性研究 总被引:1,自引:0,他引:1
本文报导C60/PMMA复合材料的制备方法,并采用调QNd:YAG倍频脉冲激光照射C60/PMMA夏合材料,研究了其反饱和吸收与光限幅将性。在线性透射率为46%条件下,光限幅阈值能量密度为65mJ/cm2,材料破坏能量密度阈值为600mJ/cm2.与C60甲苯溶液相比具有一定的优点。 相似文献
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基于C60受体和有机分子给体的太阳能电池是目前非常重要的一个研究热点, 利用同步辐射真空紫外光电子能谱(SRUPS) 技术研究了酞菁铁(FePc)与TiO2(110)及C60的界面电子结构, 以及FePc与C60分子混合薄膜的电子结构. SRUPS价带谱显示, FePc沉积在化学计量比与还原态两种不同的TiO2(110)表面时, FePc分子的HOMO能级均随FePc厚度的变化发生了移动, 而在化学计量比的TiO2(110)表面位移较大, 同时发生界面能带弯曲, 说明存在从有机层向衬底的电子转移. 在FePc/C60和C60/FePc界面形成过程中, FePc与C60分子的最高占据分子轨道(HOMO)位移大小基本相同. 由界面能级排列发现, 在FePc与C60的混合薄膜中, FePc分子的HOMO与C60分子的最高占据分子轨道能级差较大, 这有利于提高器件开路电压, 改善器件性能. 相似文献
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本文介绍了真空紫外光电离质谱结合理论计算研究环戊酮单分子的光电离解离过程. 在9.0∽15.5 eV能量范围内,测量了环戊酮离子及其碎片离子的光电离效率曲线. 通过光电离效率曲线,将环戊酮分子的电离能确定为9.23±0.03 eV,并确认碎片离子为:C5H7O+,C4H5O+,C4H8+,C3H3O+,C4H6+,C2H4O+,C3H6+,C3H5+,C3H4+,C3H3+,C2H5+, C2H4+. 利用量子化学计算方法,在ωB97X-D/6-31+G(d,p)理论水平基础上,提出了C5H8O+的解离机制. 通过对环戊酮解离路径的分析,发现开环和氢迁移过程为环戊酮离子解离的主要路径. 相似文献
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The possible existence of complexes formed by the C60 fullerene or its derivatives with transition metals interacting with the carbon cage via η6−π type bonding is discussed. The derivatives C60
R
6 of the C60 fullerene (R = −, H, F, Cl, Br, CN) are analyzed using the density functional method within the Perdew-Burke-Ernzerhof approximation.
In these molecules, the R groups are attached to carbon atoms located in the α positions with respect to the common hexagon of the C60 fullerene. The structure and electron configuration of complexes formed by these molecules with Cr(C6H6), Cr(CO)3, MoC6H6, and Mo(CO)3 particles are modeled. The “dimer” systems C60R6-M-R
6C60 (M = Cr, Mo, R =-, H, F) are investigated in which two fullerene molecules interact via a transition-metal atom. It is found that the introduction
of six R groups in the α sites with respect to the common hexagon of C60 favors the formation of complexes of these derivatives of the C60 fullerene with the Cr(C6H6), Cr(CO), Mo(C6H6), and Mo(CO)3 particles in which η6-π type bonds arise between the metal and the atoms of the hexagon fringed with the R groups. It is also demonstrated that analogous complexes with a “bare” C60 fullerene are possible, but they are significantly less stable. The (C6H6) M-R
6C60
R
6-M (C6H6) complexes of particles M(C6H6) (M= Cr, Mo) and derivatives R
6C60
R
6 (R =-, H, F, Cl, Br) are studied. In the R
6C60
R
6 molecule, six R groups are located in the α sites with respect to the common hexagon of the C60 fullerene and six other groups fringe the opposite hexagon. The obtained results can be applied to planning synthesis of
new complexes that C60 fullerene derivatives can form with transition metals.
Original Russian Text ¢ E.G. Gal’pern, A.R. Sabirov, I.V. Stankevich, 2007, published in Fizika Tverdogo Tela, 2007, Vol.
49, No. 12, pp. 2220–2223. 相似文献
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本文采用基于多体格林函数方法和Bethe-Salpeter方程(GW/BSE)的电子结构计算方法和非绝热动力学模拟研究了两种不同桥连化学键构型(5-6构型和6-6构型)的酞菁锌-富勒烯(ZnPc-C60)给受体复合物的激发态性质及其弛豫过程. 对于6-6构型,ZnPc-C60的最低激发态S1态为光谱明态,即ZnPc的局域激发(LE)态,因此,6-6构型的ZnPc-C60在光激发之后几乎不会发生电荷分离过程. 相比之下,5-6构型的ZnPc-C60的S1态是C60的LE态,为光谱暗态,而作为光谱明态的ZnPc的LE态的能量更高. 而且,在ZnPc和C60的LE态之间还存在若干电荷转移(CT)态. 因此,电荷转移会在从高能的ZnPc的LE态到低能的C60的LE态的弛豫过程中发生. GW/BSE级别的非绝热动力学模拟结果进一步验证了电子结构计算的结论,并给出了相关过程的时间尺度:从ZnPc到C60的超快激发态能量转移过程在前200 fs完成;随后发生的是由C60到ZnPc的超快空穴转移过程. 本工作表明不同的桥连化学键模式(即5-6和6-6构型)可用于调节ZnPc-C60给体-受体复合物的激发态性质及其光电性质. 与此同时,本工作证明了GW/BSE级别的非绝热动力学方法是探索非周期性给体-受体复合物、有机金属配合物、量子点、纳米团簇等复杂体系的光诱导动力学的可靠工具. 相似文献
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M. O. Baumgartner D. P. Scherrer F. K. Kneubühl 《Applied physics. B, Lasers and optics》1996,62(5):473-477
We report on optical limiting and z-scan in CS2 as a function of the pulse duration of 10 µm TEA CO2-laser radiation. We present a comprehensive and simple model for the shape of a laser pulse transmitted through this limiting device. For the first time, we propose the use of an optical limiting device for beam shaping. 相似文献
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A. R. KOST J. E. JENSEN R. O. LOUFTY J. C. WITHER 《Applied physics. B, Lasers and optics》2005,80(3):281-283
Optical limiting has been investigated for higher fullerenes and compared with C60. The transmission through an aperture placed after solutions of C76, C78, and C84 in tetrahydronaphthalene was measured using Q-switched laser pulses with a wavelength of 532 nm and a pulse width of 8 ns FWHM. Unlike C60, the transmission for these higher fullerene solutions decreased linearly with increasing optical pulse energy. We attribute the linearized optical limiting response to self-defocusing of the optical beam and the absence of excited-state absorption. The ground state absorption spectra for the higher fullerenes suggest their use for optical limiting in the near infrared, and the C84-tetrahydronaphthalene solution was found to be an optical limiter at 1.064 m. 相似文献
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Study on the optical limiting properties of the mixed liquid of carbon black suspensions and
green tea solution by multi-pulse laser 下载免费PDF全文
The optical limiting properties of the mixed liquid of carbon black
suspensions (CBS) and green tea solution were studied by using an 8
ns laser pulse at 532\,nm. The optical limiting effects of the CBS
and mixed liquid have been compared between 5 and 10\,Hz repetition
frequencies with nanosecond laser pulse. The experimental results
indicate that the optical limiting threshold of the sample with the
incidence laser at 10\,Hz repetition frequency is lower than at
5\,Hz repetition frequency. The possible reasons for the influence
of the repetition frequency on the samples are discussed. And by
observing the optical radiant distributions when the laser pulse
passing through different samples, a possible mechanism for the
observed effects is suggested. At the same time, the result shows
that the optical limiting of CBS is the dominant factor to optical
limiting of the mixed liquid. 相似文献
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Y.-P. Sun S. Gavrilyuk J.-C. Liu C.-K. Wang H. gren F. Gelmukhanov 《Journal of Electron Spectroscopy and Related Phenomena》2009,174(1-3):125
We present a dynamical theory of nonlinear absorption and propagation of a laser pulse train that contains 20 subpulses with an individual pulse width of 100 ps. It is shown that the accumulative nonlinearity and the reverse saturation absorption play important roles in the optical limiting performance and pulse shaping. When the incident field is not too strong, the population transfer reveals a slow response process, and the periodic sequence of short light pulses can be regarded as a continuous long pulse. The general theory is applied to fullerence C60, which is a popular reverse saturable absorption material and a good limiter because of its larger excited-state absorption cross-section compared with that of the ground state. The propagation of the front subpulses is mainly affected by the linear transition between the ground state and the first excited singlet state, while the latter subpulses are attenuated by the excited-state absorption. Moreover, these two different kinds of absorption mechanisms result in different radial distributions for different subpulses. The pulse propagation is studied by solving numerically the coupled rate equations and the propagation equation of the optical pulse intensity, using experimental parameters as input. We suggest a new method to measure the lifetime of the triplet state. 相似文献
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为了提高高功率激光光束质量和改善近场均匀性,在SILEX-Ⅰ超短脉冲激光装置的泵浦光系统上进行实验,研究了一种双光子吸收材料的光限幅特性及对激光近场的改善情况。利用泵浦光SAGA激光器输出的激光进行光限幅特性实验。结果表明:该材料具有明显的光功率限幅特性,且透过率较高,当入射光强小于0.60 GW/cm2时,透过率大于90%。在SILEX-Ⅰ装置的泵浦光系统进行联机实验,研究了该材料对激光近场均匀性的改善。实验结果表明:经过材料后,激光近场均匀性和调制度有明显改善。 相似文献
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Quanshui Li Chunling Liu Qihuang Gong Jining Gao Limin Qi 《Journal of nanoparticle research》2009,11(4):989-993
In order to reveal the optical limiting mechanisms of semiconductor hollow spheres, the nonlinear optical properties of CuS
and Cu2O hollow spheres were investigated via the fluence-dependent transmittance and the nonlinear scattering measurements. The
CuS and Cu2O hollow spheres have similar morphologies and different types of optical band-gap. The experimental results show that the
optical limiting performance of CuS is better than that of Cu2O, although the nonlinear scattering of Cu2O is stronger than that of CuS. Free-carrier absorption based on the delocalized carriers (holes) in CuS is believed to play
an important role in the optical limiting effects. The merits of the structure of semiconductor hollow spheres used for optical
limiting were discussed. 相似文献
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M.D. Zidan M.B. Alsous A.W. Allaf A. Allahham A. AL-Zier 《Optics & Laser Technology》2012,44(7):2282-2285
The optical limiting action of C60 doped poly(ethylacetylenecarboxylate) polymer has been carried out using Pulse Nd-YAG laser at 532 nm as the source of excitation. The optical limiting measurements were performed at three different doping concentrations. The optical limiting efficiency of the C60 doped poly(ethylacetylenecarboxylate) polymer was studied at various doping concentrations, the threshold limiting fluence at 0.15 J/cm2 was observed with transmission of about 89%. An explanation based on the combination of two-photon absorption and reverse saturable absorption was proposed for its nonlinear optical absorption behavior. 相似文献
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M.D. Zidan M.B. Alsous A.W. Allaf A. Allahham A. AL-Zier 《Optics & Laser Technology》2011,43(7):1343-1346
The optical limiting action of poly(dimethylacetylendicarboxylate) polymer doped with fullerene C60 has been investigated under irradiation with 10 ns laser pulses at 532 nm. The optical limiting measurements were performed at four different dopant concentrations. The threshold limiting fluence at 0.3 J/cm2 was observed at high doping concentrations, with transmission of about 55%. An explanation based on the combination of two-photon absorption and reverse saturable absorption was proposed for its nonlinear optical absorption behavior. 相似文献