Dopant Material

To match up with host materials, the basic requirements for the guest or dopant materials are ... 

The dopant materials should have phase compatibility with the host materials. 

SCHEME 3.59 An asymmetric mono(styryl) amine as a deep blue dopant material. 

Same as arylamine DSA derivatives used as guest materials in blue OLEDs, Geise et al. synthesized a series of alkyloxy-substituted biphenyl vinyl compounds as dopant materials [236]. These authors studied OLEDs fabricated using PVK as a host polymer and holetransporting PBD as a codopant with a PLED structure of ITO/PEDOT-PSS/PVK 230VBP PBD/LiF/Al, which gave an optimized QE of 0.7% and brightness of 1600 cd/m2 at 100 mA/cm2 with emission peak at 450 nm. 

Perylene (199) and its derivative (TBP, 200) have been widely used as blue dopant materials owing to their excellent color purity and stability. Efficient blue emitters with excellent CIE coordinates are found in biaryl compound 2,2 -bistriphenylenyl (BTP, 201) as shown in Scheme 3.62 [145]. A device of structure ITO/TPD/BTP/TPBI/Mg Ag emits bright blue emission with CIE (0.14, 0.11). A maximum brightness of 21,200 cd/m2 at 13.5 V with a maximum EQE of 4.2% (4.0 cd/A) and a power efficiency of 2.5 lm/W have been achieved. 

Another important early advance made by Tang et al. [7] is the use of fluorescent doping, i.e., the addition of a small percentage of an emissive fluorescent material into a host matrix. This can be used to alter the color of emission, in addition to improving the efficiency and the lifetime of devices. The technique of simultaneously vapor depositing the host and the fluorescent dopant material is now widely used in the field of OLEDs. 

Another very interesting example was presented by Huang et al. in 2011 [108], They used 15-crown-5-functionalized MWCNTs as dopant material (Fig. 18.6). The main incentive for their work is based on the binding Li+ ions that are present in the electrolyte by means of crown ether complexation. As a matter of fact, Li+ is expected to attract 1 ions, which would render any movement difficult within the electrolyte... 

Uses/Sources. In wood preservatives metallurgy for hardening copper, lead, alloys pigment production manufacture of certain types of glass insecticides and fungicides, rodent poison a by-product in the smelting of copper ores dopant material in semiconductor manufacmre... 

Elemental forms of gallium and arsenic, plus small quantities of dopant material — silicon, tellurium or chromium — are reacted at elevated temperatures to form ingots of doped single-crystal GaAs. 

Both step index and graded index fibers have been prepared by this process, using Ge02 und B203 as dopant materials. Deposition efficiencies of about 45% have been obtained. The deposition rate is typically between 0.4—1.6 g/min and blanks yielding 10 km fibers have been made. 

In a second embodiment the strip detectors A to H are mounted on an intrinsic p-type silicon substrate 3A covered by a silicon oxide layer 3B. A patterned arrangement of conductor tracks 21 is formed in the semiconductor base 3B. Each track is formed by diffusion or ion-implantation of an n-type dopant material, and isolated from adjacent tracks by means of a channel stop network 23. Bridging links of nichrome-gold are formed to define and connect the read-out regions to the tracks 21. The links 25 are paired and thus provide voltage detection contacts. The tracks 21 are connected to connection pads 29. Signal processing circuitry is incorporated in the semiconductor base layer 3B. 

Figure 6 displays the energy levels of common donors and acceptors with reference to the band edges of two semiconductors. If the energy levels of these donors and acceptors are close to the conduction or valence bands, respectively, they are called shallow donors or acceptors. Dopants with energy levels that are further away from either band are called deep dopants. While ionization of shallow dopants is usually complete at room temperature, ionization of deep dopants generally does not occur at room temperature. Shallow dopant materials are considered primarily in the remainder of this section. 

Liquid doping sources are usually of two forms (1) a solution of dopant material is directly applied to the semiconductor surface and dried prior to diffusion or (2) a carrier gas is bubbled through the liquid source and the source molecules are carried into an open-tube furnaee. Doping may then occur from the gas phase or from a deposited solid phase on the semiconductor. Also, in some cases solid sources deposited on semiconductors become liquid at diffusion temperatures (e.g., borosilicate glasses containing ca. 30 mol% B2O3 become liquid at 1000°C)L... 

Here, we describe the design concept of hole-transport materials (HTMs), electron-transport materials (ETMs), emitter materials (EMs), and dopant materials. We also mention the material design for obtaining highly efficient and durable OLED devices. 

Dopant materials (DMs) are other keys for obtaining not only high EL quantum efficiency but also durable device performance. We know of various organic... 

FIGURE 2.10. Molecular structures of dopant materials blue to red materials are shown in sequence. 

Additional attempts have been presented to render hosts with the fluorite and the related pyrochlore structure electronically conductive by doping with mixed-valence and/or shallow dopants. The list of dopant materials examined includes oxides of elements of, for example, Ti, Cr, Mn, Fe, Zn, Fe, Sn, Ce, Pr, Gd, Tb and U. In general, however, the extent of mixed conductivity that can be obtained in fluorite-type ceramics is rather limited, by comparison with the corresponding values found in some of the perovskite and perovskite-related oxides considered in the next section. 

In past years, the analysis of doped dielectric MOS films has always led to the conclusion that the dopant materials existed in their fully oxidized state. Thus, phosphorus existed as phosphorus pent-oxide and as such could easily be quantitatively measured in aqueous solutions as the phosphate ion. Although many suspected the presence of phosphorus trioxlde, there was no evidence of its existence. 

To evaluate hole-transporting ability of newly synthesized phenylnaphthyldiamine derivative HIM 2, we fabricated the hole-dominant device using HTM 2 as a hole-transporting material with structures as follows 1TO/2-TNATA/HTM 2/EML/Al (device 11). On TTO substrate, 4, 4"-tris(N-(naphth-2-yl)-N-phenyl-amino)tri- phenylamine (2-TNATA) was previously deposited as a hole-injecting material. IDE 215 doped with 3 % of IDE 118 (host and dopant materials by Idemitsu Co., LTD) was used as blue emitting layer. 

In reality, the process may be much more difficult as described in the model given above. Further problems are evaporation losses of the dopant material at the way through the flame or even from the molten layer, hampered mixing and transport in the small molten volume, inhomogenieties of the Uquid phase as well as a non-flat phase boundary. 

Lewis DR Dopant materials used in the microelectronics industry. State of the Art Reviews in Occupational Medicine 1 35-47,1986 Maroni M, Colombi A, Buratti M, et al Human exposure to vanadium and nickel from fuel-oil combustion residues, in Heavy Metals in the Environment, Vol 2. Edited by Lindberg SE, Hutchinson TC. Edinburgh, CEP Consultants, 1987, pp 101-103... 

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