Models for intrinsic and extrinsic elastico and plastico-mechanoluminescence of solids
Models for intrinsic and extrinsic elastico and plastico-mechanoluminescence of solids
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DOI：
10.1016/j.jlumin.2013.01.024
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发表时间：
2013-06
影响因子：
3.6
通讯作者：
V. Chandra;B. P. Chandra;P. Jha
中科院分区：
文献类型：
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作者：
V. Chandra;B. P. Chandra;P. Jha
大量固体表现为外在弹性-机械发光（ML）和外在塑性发光（ML），只有少数固体表现为本征弹性-机械发光（ML）和本征塑性发光（ML）。而大量固体的弹性-机械发光和塑性- ML是由电子俘获和电子轰击机制引起的，只有少数固体的弹性-机械发光和塑性- ML是由化学发光和其他机制引起的。稀土掺杂的铝酸锶、稀土掺杂的硅酸锶和某些其他晶体的弹性ML是如此强烈，以至于可以在白天用肉眼看到。很长一段时间，探测金属的发光被认为是不可能的；然而，现在已经发现，某些金属的内在ML可以通过其快速的塑性变形产生。在浸没于液氮中的紫外辐照CdS单晶中，只需沿其c轴轻敲即可产生类似边缘发射的本征弹性ML。通过在整个表面或多或少均匀地敲击，可以从一个受到良好激发的晶体中获得1000次闪光。在刺激耗尽后，晶体可以通过短暂的紫外线照射重新激活，并且可以重复通过敲击获得多次闪光的过程。某些未辐照的碱卤化物晶体的塑性ML光谱与相应的X或γ辐照晶体的塑性ML光谱相似。这一结果可以通过固定位错与运动位错相交时f中心和孔中心的形成来理解。根据当时的条件，在II-VI半导体和某些未辐照的碱卤化物晶体中可以观察到连续的塑性ML或脉冲塑性ML。弹性ML的光谱类似于固态发光光谱，而根据固体的不同，塑性ML的光谱要么仅由固态发光光谱组成，要么由固态发光光谱与周围气体吸附分子的放电光谱组合而成。到目前为止，弹性ML和塑性ML只在有限的固体中进行了研究，因此，它们还需要进一步的研究。橡胶和聚合物的弹性ML和塑性ML的研究可能是非常有趣的。了解本征和外征弹性和塑性机械发光的机理有助于制备合适的弹性和塑性机械发光材料，也有助于设计基于弹性和塑性机械发光的器件。理论工作者需要这些现象的模型或机理来提出和发展他们的理论，实验工作者也需要这些现象的模型和机理来改进他们的材料和器件。在这方面，本研究也可能是有用和重要的。
A large number of solids exhibit extrinsic elastico–mechanoluminescence (ML) and extrinsic plastico ML, only a few solids exhibit intrinsic elastico ML and intrinsic plastico ML. Whereas the elastico ML and plastico ML of a large number of solids are caused by the electron trapping and electron bombardment mechanisms, the elastico ML and plastico ML of only a few solids are caused by the chemiluminescence and other mechanisms. The elastico ML of rare earth doped strontium aluminate, rare earth doped strontium silicates and certain other crystals is so intense that it can be seen in day light with naked eye. For a long time, the detection of luminescence of metals was considered to be impossible; however, now-a-days, it has been found that the intrinsic ML in certain metals can be produced by their plastic deformation at fast rate. In an ultraviolet-irradiated CdS single crystal immersed in liquid nitrogen, the intrinsic elastico ML resembling edge emission can be produced simply by tapping it along its c-axis. Of the order of a 1000 flashes may be obtained from a well-stimulated crystal by tapping more or less uniformly over the whole surface. After the stimulation is exhausted, the crystal can be re-activated by a brief ultraviolet illumination, and the process of obtaining multiple flashes by tapping can be repeated. The spectra of the plastico ML of certain non-irradiated alkali halide crystals resemble the plastico ML spectra of the corresponding X- or γ-irradiated crystals. Such result can be understood on the basis of the formation of F-centres and hole centres during the intersection of the forest of immobile and mobile dislocations. Depending on the prevailing conditions, either the continuous plastico ML or pulsed plastico ML is observed in II–VI semiconductors and in certain non-irradiated alkali halide crystals. Whereas the spectra of elastico ML resemble the solid state luminescence spectra, depending on the solids the spectra of plastico ML consist of either only the solid state luminescence spectra or the combination of solid state luminescence spectra and discharge spectra of the adsorbed molecules of surrounding gases. Till now the elastico ML and plastico ML have been studied only in a limited number of solids, and therefore, they need further investigation. The study of the elastico ML and plastico ML of rubbers and polymers may be very interesting. The understanding of the mechanisms of intrinsic and extrinsic elastico ML and plastico ML may be useful in preparing suitable elastico and plastico mechanoluminescent materials and it may be helpful in designing the devices based on elastico ML and plastico ML. Theorists need the models or mechanisms of the phenomena to propose and develop their theories and experimentalists also need the models and mechanisms of the phenomena for improving their materials and devices. In this regard, the present study may also be useful and important.