Transparent organic thin film transistors with WO3/Ag/WO3 source-drain electrodes fabricated by thermal evaporation

Abstract

High-performance transparent organic thin film transistors using a WO3/Ag/WO3 (WAW) multilayer as the source and drain electrodes have been developed without breaking the vacuum. The WAW electrodes were deposited by thermal evaporation at room temperature, leading to little damage to organic film. The optimized WAW electrode shows high transmittance (86.57%), low sheet resistance (11 Ω/sq), and a high work function (5.0 eV). Consequently, we obtained high performance devices with mobility of 8.44 × 10−2 cm2/V · s, an on/off ratio of approximately 1.2 × 106, and an average visible range transmittance of 81.5%.

Solution‐Processed Ultrathin Organic Semiconductor Film: Toward All‐Transparent Highly Stable Transistors

“…The HOMO of PSeTPTI is -5.4 eV, a big mismatch with the work function of Ag (-4.3 eV). The work function of WAW electrode is about −5.0 eV, [ 35 ] much closer to HOMO of PSeTPTI. In Figure 5 b, the high transparency of the transparent device is clearly shown when comparing with that of the device array with thick active layer and nontransparent Au-Ag metal electrodes (the logo under the transparent device can be seen clearly).…”

“…Here, WAW is chosen as the source-drain and gate electrode, it can be deposited by thermal evaporation without damaging the organic layer and WO 3 is a p-type buffer layer which is benefi cial for hole transport. [ 35 ] With WAW electrodes, PSeTPTI ultrathin semiconductor fi lm and PMMA dielectric layer, transparent top-gate transistors were constructed. Figure 5 a displays the device structure and related energy levels.…”

Strategy for preparation of transparent organic thin film transistors with PEDOT:PSS electrodes and a polymeric gate dielectric

“…In order to construct flexible, lightweight devices, the use of temperature-sensitive polymers, however, would be highly desirable and compatible with the use of organic semiconductors (OSCs) in the logic circuit. Therefore a growing interest in incorporating OSCs into the field of transparent electronics can be noticed [7][8][9][10]. This may then allow the development of applications such as all organic flexible displays [4] or transparent sensors [11].…”

Transparent and transferrable organic optoelectronic devices based on WO3/Ag/WO3 electrodes

“…12,13 Thus, the indium-free and flexible multilayer structure are promising electrodes for transparent and flexible applications. Multilayer electrodes have been applied in organic light-emitting diodes (OLEDs), 11,14 transparent organic field-effect transistors (OFETs), 15 and organic solar cells (OSCs). [16][17][18] But, there are no reports about their application in transparent or transferrable organic photodetectors.…”

“…16 Recently, WO 3 /Ag/WO 3 (WAW) transparent electrodes were used to make transparent OFET. 15 In this study, we fabricate transparent organic photodetectors with the thermally evaporated transparent WAW electrodes showing average transmittance of 82.5% and sheet square of 20 X/sq. The photodetector works well with WAW electrodes instead of pure metal films, and shows photo responsivity (R) of 0.01 A/W and photocurrent/darkcurrent ratio (P) of 92.…”