CdS nanorods

Kang Y, Kim D (2006) WeU-ahgned CdS nanorod/conjugated polymer solar cells. Sol Energy Mater Sol Cells 90 166-174... 

Li, F. Zhang, Z. 2005. Synthesis of high quality CdS nanorods by solvothermal process, and their photoluminescence./. Nanoparticle Research 7 685-689. 

Chen et al. reported on a general approach by which the polarization of the emission from semiconductor nanorods can be manipulated by an external bias. In their device, the composite of a nematic liquid crystal mixture (E7, Merck) and nanorods (CdS) filled into an ITO-coated cell with an optimized concentration of one CdS nanorod per 1010 LC molecules was used to achieve the highest polarization ratio of the suspended nanorods [447, 448]. The nematic liquid crystal in this system acts as a solvent and media whose direction of alignment can be tuned by an applied electric field. Hence, the orientation of the CdS nanorods can be fine-tuned by an external bias because of the anchoring force between the liquid crystal... 

Figure 9. (b) TEM images of CdS nanorods (left) and CdS nanoparticles (right). 

By choosing ligand solvents, nanocrystalline CdE can be synthesized by the reactions of CdC204 with E (E = S, Se or Te) in polyamines such as en, diethy-lenetriamine and triethylenetetramine. CdS nanorods (Figure 7.29(a)) and nano-... 

The en molecules play an important role in controlling the nucleation and growth of the CdS nanorods. As a bidentate ligand, en molecules may react with Cd + ions and form relatively stable complexes. Under appropriate solvothermal conditions, the complexes become unstable and decompose, which results in the formation of CdS nanorods [lOOj. A mono-dentate ligand, n-butylamrne, was found to be a shape controller for nanorods of CdS and MSe (M = Zn, Cd or Pb) [101]. Similarly, the precursor of ZnE(en)o.s (E = S, Se) could also form in en which then is converted to ZnSe nanopartides via pyrolysis in solvothermal conditions [102]. The coordinating ability of the solvent was found to play an important role in the nucleation and growth of nanocrystallites [103]. 

D. V. Talapin, E. V. Shevchenko, C. B. Murray, A. Kornowski, S. Forster, and H. Weller. Cdse and CdSe/CdS nanorod solids. J. Am. Cherrt Soc., 126 12984-12988, 2004 M. Adachi, Y. Murata, J. Takao, J. T. Jiu, M. Sakamoto, and F. M. Wang. Highly efficient dye-sensitized solar cells with a titania thin-film electrode composed of a network structure of single-crystal-hke Ti02 nanowires made by the oriented attachment mechanism. J. Am. Chem. Soc., 126 14943-14949,2004... 

There are many examples of the self-assembly of nanoparticles to nanorods (1) self-assembly of CdS nanoparticles to CdS nanorods by oriented attachment (119), (2) self-assembly of Ti02 nanoparticles to Ti02 nanorods (120), (3) self-assembly of doped ZnS nanoparticles to single crystalline ZnS nanorods (121), (4) self-assembly of ZnO nanoparticles to ZnO nanorods (122, 123) and (5) self-assembly of Ce02 nanoparticles to Ce02 nanorods. The self-assembly of ZnO nanoparticles (nanodots) to nanorods (122) is discussed below. 

Recently, synthesis of semiconductor nanorods (nanowires or nanoflbers) and investigation of their properties have aroused much interest. Ge et al. (2002) showed that irradiation technique can be very useful in this regard as well. Cadmium sulfide (CdS) nanorods were successfully prepared by y-irradiation at room temperature and ambient pressure using urea as the template. X-ray diffraction (XRD) pattern showed that the phase of the product was hexagonal. The mean diameter of the nanorods was about 40 nm and the length was up to about 100 nm. The ratio between the length and the width is as high as 5 2. More importantly, they demonstrated that the successful obtainment of nanorods was determined by not only the presence of urea in the system but also the crystallization rate of urea from the solution. 

Efforts have also been made to control the morphology of the hybrid-based active layer and to regulate interfacial structure of NCs within the CP matrix at the nanoscopic level. Watt et at [191] grown PbS nanocrystals directly in the MEH-PPV matrix and obtained PCE of 1.1%. Similarly, Liao et at [177] synthesized CdS nanorods in P3HT matrix and achieved PCE of 2.9%. Recently, Ren et at [192] utilized the so-called chemical grafting method... 

L. Wang, Y. Liu, X. Jiang, D. Qin, Y. Cao, Enhancement of Photovoltaic Characteristics Using a Suitable Solvent in Hybrid Polymer/Multiarmed CdS Nanorods Solar Cells. Journal of Physical Chemistry C 2007, 111, 9538-9542. 

Lu X, Zhao Y, Wang C, Wei Y (2005) Fabrication of CdS nanorods in PVP fiber matrices by electrospinning. Macromol Rapid Commun 26 1325-1329... 

Semiconductor nanorods are very promising for the future development of ET-based switches controlled by an electric field. In particular, CdSe/CdS nanorods exhibit a large quantum-confined Sfark effect at the single-particle level, which enables direct control of the spectral resonance between donor and acceptor required for nanoscopic Forster-type ET in single nanorod-dye couples.The applied electrical field, in fact, allows to tune... 

Chen F, Qiu W, Chen X, Yang L, Jiang X, Wang M, Chen H (2011) Large-scale fabrication of CdS nanorod arrays on transparent conductive substrates from aqueous solutions. Sol Energy 85 2122... 

Wang L, Liu Y, Jiang X, Qin D, Cao Y (2007) Enhancement of photovoltaic characteristics using a suitable solvent in hybrid polymer/multiarmed Cds nanorods solar cells. J Phys Chem C 111 9538-9542... 

Fig. 3.17 Schematic representation of the experimental platform for atomic scale insight into photocatalytic nanosystems. Colloidal semiconductor nano crystals (CdS nanorods) are spin-coated onto ITO substrates (a) followed by deposition of cluster under UHV conditions (b). The resulting samples are investigated for their photocatalytic activity in terms of hydrogen generation efficiency in aqueous solution (c). Reprinted (adapted) withpermissionfrom [22] - Copyright (2012) American Chemical Society.

Talapin and co-workers demonstrated the effect of the chain length of capping ligands on determining the polytypes of the CdSe NCs. They synthesised CdSe/CdS nanotetrapods by the injection of trioctylphosphine sulfide (TOPS) solution to a mixture of CdO, n-octadecylphosphonic add (QDPA), TOP, TOPO and n-propylphosphonic acid (PPA) heated at 300 °C followed by the addition of 3.5 nm ZB-CdSe seeds at 315 °C. However, only CdSe/CdS nanorods were obtained in the absence of PPA in the reaction system due to the conversion of ZB-CdSe seeds into W phase. This showed that long chain ligand (ODPA) favoured the W-CdSe phase, whereas the addition of PPA stabilised the ZB phase by preventing the phase transformation which was critical for the formation of nanotetrapods. 

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