Application in devices

In the 1980s, CdSe quantum dots vere prepared by top-dovm techniques such as lithography ho vever, size variations, crystal defects, poor reproducibility, and poor optical properties of quantum dots made them inadequate for advanced applications. Introduction of bottom-up colloidal synthesis of CdSe quantum dots by Murray et al. [3] and its further advancements brought radical changes in the properties of quantum dots and their applications in devices and biology. The colloidal syntheses of CdSe quantum dots are broadly classified into organic-phase synthesis and aqueous-phase synthesis. 

Second-order nonlinear optics (NLO) has several applications in the field of optoelectronics.11 Several of these nonlinear processes are straightforward to experimentally demonstrate but their application in devices has been hampered by the lack of appropriate materials. Necessary requirements for second-order nonlinear optical materials include the absence of centrosymmetry, stability (thermal and mechanical), low optical loss, and large and fast nonlinearities.8... 

Figure 11.2 The formation of excitons [9]. (Reprinted with permission from Y. Shirota and H. Kageyama, Charge carrier transporting molecular materials and their applications in devices, Chemical Reviews, 107, 953-1010, 2007. 2007 American Chemical Society.)...

Fullerene has important properties as a nonlinear material, particularly as an optical limiting material with applications in device fabrication. The poor solubility of this material and the processing difficulties associated with it severely limit its direct application, however. One possibility of overcoming these disadvantages involves binding polymers on to Ceo to obtain fullerene-based polymeric materials with peculiar physical and/or chemical properties and good processability. 

Figure 23.9. Photodegradation of the photoluminescence intensity from nc-Si/Si02 nanocomposites upon prolonged illumination with the excitation radiation for both the "red" PL and the fast PL from W -doped nc-Si/Si02 nanocomposites. The photodegraded sample can be recovered by annealing in forming gas (FG) as described above, but this is not of any use for applications in devices.

Table I. Summary of Ion Implantation Applications in Device Fabrication...

Charge carrier transporting heterocycle-derived molecular materials and their applications in devices 07CRV953. 

For all of the samples studied and for particle sizes down to the lowest studied, 150 nm, very similarly shaped SCO transition curves were observed and taken to imply that no significant size effect influenced the SCO process, at least in these particular nano-objects. Nanocrystals of the 3D coordination polymer [Fe(prazine)Pt(CN)4], which displays SCO properties in the bulk, also preserve the same magnetic, structural and optical bistability for particle sizes on the order of 50 nm. Recent evidence suggests however that this may not always be the case, as in the example of the 2D coordination polymer [Fe(3-fluoropyridine)2M(CN)4] where the bulk SCO properties were shown to be very markedly influenced by the nanoparticle dimen-sions. Detailed discussion of this topic falls outside the scope of this review but we refer to it here because it is an aspect of spin crossover studies that bears fundamentally" " on the practical application in device teehnology of nano-dimensioned SCO materials, which continue to display hysteretie behaviour at such dimensions. 

Pyroelectric ceramics can be used to detect any radiation that produces a change in the temperature of the crystal, but are generally used for IR detection. Because of their extreme sensitivity a rise in temperature of less than one-thousandth of a degree can be detected. This property finds application in devices such as intruder alarms, thermal imaging, and geographic mapping. 

Abstract The combination of nanomaterials and ordered deformable soft materials is emerging as an enabling system in nanoscience and nanotechnology. In this context, nanomaterial functionalized photoresponsive liquid crystalline polymers are very promising and versatile systems due to their dynamic function. Moreover, the unique characteristic of nanomaterials combined with the mechanical, self-organizing and stimuli-responsive properties of deformable liquid crystalline polymers opens up new and exciting possibilities. In this chapter, we present recent developments of photodeformable behaviors of liquid crystalline polymers functionalized with nanomaterials. The main emphasis revolves around how the physicochemical properties of different nanomaterials modulate the reversible photomechanical behaviors of liquid crystalline polymers and their potential application in devices such as optically controlled switches and soft actuators. 

The Liquid Crystals book series publishes authoritative accounts of all aspects of the field, ranging from the basic fundamentals to the forefront of research from the physics of hquid crystals to their chemical and biological properties and, from their self-assembhng structures to their applications in devices. The series will provide readers new to liquid crystals with a firm grounding in the subject, while experienced scientists and liquid crystallographers will find that the series is an indispensable resource. 

The theoretical and experimental results on physical properties of liquid crystals were reviewed by de Gennes [15], Chandrasekhar [16], de Jeu [17], Sonin [18], Belyakov and Sonin [19], Vertogen and de Jeu [20], and others. The electrooptical effects were discussed by Kapustin [21], Pikin [22], and Blinov [23]. Recent results on liquid crystalline materials and their application in devices can be found in [24-26, 29]. 

Nanocrystalline semiconductor materials [ 1 ] exhibit a wide range of novel chemical and physical properties that are finding applications in devices such as solar cells... 

Though the details of its various applications are available in some books devoted on liquid crystals and their applications, it may be interesting to introduce the basis of its application in devices that is based on its anisotropic optical property, particularly under electric or magnetic field [9]. 

Due to the strong anisotropy of liquid crystals, field effects are accompanied by dramatic changes in optical properties. The electro-optical properties of liquid crystals have been studied very actively since the beginning of the century, and many important phenomena have been discovered. The earlier theoretical and experimental results on the physical properties of liquid crystals, including certain electric field effects, have been reviewed in a variety of books [1-5], as have the details of electro-optical effects [6-9], and many results relating to the properties of liquid crystalline materials and their application in devices have been reported [10-12]. 

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