PbSe nanocrystals

Figure 10.10. (a) Optical absorption spectrum of a colloidal solution of 8-nm PbSe nanocrystals, (b) TEM image of an array of 8-nm PbSe nanocrystals, (c) GISAXS pattern of a PbSe nanocrystal film. The appearance of well-resolved reflections confirms both in-plane and vertical ordering of the PbSe nanocrystals. Reproduced from Ref. 68, Copyright 2005, with permission from the A A AS. 

Figure 10.12. Device characteristics of PbSe nanocrystal FETs activated with hydrazine. (a) Plots of 7d and 7 2 versus VG at constant VDS = 40 V for an n-channel FET assembled from 8.1-nm PbSe nanocrystals. L = 8 xm, W = 2300 tm. (b) ID versus VG plot at constant VDS = IV for an ambipolar FET assembled from 8.1-nm PbSe nanocrystals. L = 8 xm, W = 2300 xm. (c) Plots of 7D and 7 2 versus VG at constant Fps = -40V for a p-channel FET assembled from 8.2-nm PbSe nanocrystals. L = 10 tm, W = 3000 xm. (d) Plot of 7D versus FDS, as a function of VG for a p-channel FET assembled from 8.4-nm PbSe nanocrystals. L = 8 xm, W = 2300 xm. The changes in the transistor polarity were induced by controllable adsorption/desorption of hydrazine molecules from the nanocrystal surface. Reproduced from Ref.68, Copyright 2005, with permission from the AAAS.

Talapin, D. V. Murray, C. B. 2005. PbSe nanocrystal solids for n- and p-channel thin film field-effect transistors. Science 310 86-89. 

Fig. 2.3 (a) Star-shape PbSe nanocrystals and tb e) radially branched nanowires, (d) TEM image of the (100) view of the branched nanowire and the corresponding selected area electron diffraction pattern, (e) TEM image of the (110) view of the branched nanowire and the corresponding selected area electron difl raction pattern. Reprinted with permission from K.-S. Cho, D. V, Talapin, W Gaschler and C. B. Murray, J. Am. Chem. Soc., 2005,127, 7140. 2005 American Chemical Society. 

R. Schaller, V. Klimov, High efficiency carrier multiplication in PbSe nanocrystals Implications for solar energy conversion, Phys. Rev. Lett. 92 (2004) 186601. 

Cui D., Xn J., Zhn T., Paradee G., Ashok S. and Gerhold M. (2006), Harvest of near infrared light in PbSe nanocrystal-polymer hybrid photovoltaic cells , Appl. Phys. 

Fig. 8 (a) TEM image of as-prepared cube-like PbTe nanocrystals. Inset shows the SAED pattera, (d) Ordered array consisting of 15 nm cubic-shaped PbSe nanocrystals after size selective precipitation. Reprinted with permission from X E, Murphy, M. C. Beard, A. G. Norman, S. P. Ahrenkiel, J. C. Johnson, P. Yu, O. 1. Micic, R. X. Ellingson and A. X Nozik, J. Am. Chem. Soc, 2006, 128, 3241. 2006 American Chemical Society. 

PbSe and cubic ZnS nanowires as well as complex one-dimensional nanostructures can be obtained in solution through oriented attachment of nanocrystals. In Fig. 23, star-shaped PbSe nanocrystals and branched nanowires are shown. 

Several papers have discussed the role of oriented attachment in the anisotropic growth of nanocrystals. A recent paper by Cho and coauthors [50] discusses the oriented attachment process as the main mechanism involved in the construction of anisotropic PbSe nanocrystals in several shapes. The authors used the proposition of... 

D. Cui, J. Xu, T. Zhu, G. Paradee, S. Ashok, M. Gerhold, Harvest of Near Infrared Light in PbSe Nanocrystal-Polymer Hybrid Photovoltaic Cells. Applied Physics Letters 2006, 88, 183111. 

Fig. 12 TEM images and SAED pattern of PbSe nanocrystals with different shape, Reproduced from ref. 114 with permission from the Royal Society of Chemistry,...

A phosphine-free, low-temperature colloidal method for the eontrolled synthesis of PbSe nanocrystals in both zero-dimension (OD) and one-dimension (ID) was demonstrated by Li et. ID Pb(OH)Cl nanowires ( 80 to 160 nm in diameter) is directly used as a Pb preeursor and reacted with a Se precursor to form monodisperse dot-shaped OD cubie PbSe and ID orthorhombic PbSe nanowires. The authors highlighted the novelty of the method in that a fast nucleation step has been skipped and high quality OD and ID PbSe nanocrystals can undergo controlled synthesis within a relatively slow reaction time (2 to 24 h). The nanowires had a mean diameter of 15-24 nm. 

C. Other nanostructures are also obtained by this preparation [243]. A solvothermal reaction in the presence of octadecylamine yields monodisperse PbSe nanocrystals of controllable size [244]. A low-temperature one-pot synthesis of HgTe nanocrystals has been described without the use of toxic precursors. The particles show infrared photoluminescence [245]. 

Trinh MT, Houtepen AJ, Schins JM, Hanrath T, Pins J, Knulst W, Goossens APLM, Siebbeles LDA (2008) In spite of recent doubts carrier multiplication does occur in PbSe nanocrystals. Nano Lett 8 1713-1718... 

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