tailieunhanh - Organic Light Emitting Diode Material Process and Devices Part 11

Tham khảo tài liệu 'organic light emitting diode material process and devices part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Transparent Conductive Oxide TCO Films for Organic Light Emissive Devices OLEDs 241 However since Cd and its compounds are highly toxic the utilization of these TCOs is limited though they have adequate electrical and optical properties. Other binary TCOs were synthesized from known binary TCOs and also from non-TCO compounds such as In6WO12 and the p-type CuAlO2. All of the TCOs discussed above are n-type TCOs. In addition p-type doped TCOs were also developed and could find interesting future applications in particular as a new optoelectronic field like transparent electronics . Banerjee Chattopadhyay 2005 The need to produce n-type TCOs with higher conductivity and better transmission without relying on In gave rise to research and development effort for new TCOs. Recently mobility with more than twice that of commercial ITO was achieved in Mo-doped In2O3 IMO and this material showed that the conductivity can be significantly increased with no changes in the optical transmittance upon doping of Mo. Meng et al. 2001 Yoshida et al. 2004 Electronic band structure of IMO was investigated by Medvedeva it was revealed that the magnetic interactions which had never been considered to play a role in combining optical transparency with electrical conductivity ensure both high carrier mobility and high optical transmittance in the visible range. Medvedeva 2006 Recently new thin film geometries were also explored by Dingle et al. in search of TCO films with higher conductivity. Dingle et al. 1978 They showed that higher conductivity could be obtained by doping modulation which spatially separates the conduction electrons and their parent impurity atoms ions and thereby reduced the effect of ionized and impurity scattering on the electron motion. Rauf used a zone confining process to deposit ITO with r W-cm and m 103 cm2 Vs. Rauf 1993 The highly and lowly doped regions were laterally arranged in the films rather than vertically as in superlattice structures. A .