Modulation of indium–tin oxide work function by a versatile self-assembled monolayer measured with the scanning Kelvin nanoprobe

2011 ◽  
Vol 89 (12) ◽  
pp. 1512-1518 ◽  
Author(s):  
Christophe Blaszykowski ◽  
Larissa-Emilia Cheran ◽  
Michael Thompson

In molecular optoelectronics, high-quality contacts at electrode|organics interfaces are crucial for charge carriers to efficiently flow through and therefore play a critical role on device performance. Electrode surface morphology, adhesibility, wettability, and work function are thus many parameters that must be accurately controlled, which is achievable using self-assembling monolayer (SAM) surface chemistry. Herein, we employ this technique to alter the electronic and surface energy-related properties of indium–tin oxide (ITO). In comparison to unmodified ITO, the newly introduced SAM-derivatized surface exhibits limited wettability and considerably higher work function (ΔΦ = ~1.2 eV). Several applications are proposed for this organic coating, notably at the anode of organic light-emitting diode (OLED) devices for decreasing the hole injection barrier or as an atmospherically stable protective layer in the coatings industry.

2001 ◽  
Vol 708 ◽  
Author(s):  
Chimed Ganzorig ◽  
Masamichi Fujihira

ABSTRACTIndium-tin-oxide (ITO) is the most widely used material as a transparent electrode due to its excellent transparency and high conductivity. The devices based on bare ITO, however, exhibited inefficient hole injection due to insufficient high work function and required high drive voltages. Thus, various surface treatments of ITO have been attempted to change the work function of ITO in order to reduce the hole injection barrier height. Electroluminescent (EL) characteristics of devices were improved dramatically using ITO chemically modified with H-, Cl-, and CF3-terminated benzoyl chlorides. By the use of reactive -COCl groups, ITO surfaces were modified quickly and the work function of the modified ITO was changed widely depending upon the permanent dipole moments introduced in p-position of benzoyl chloride. We also compared the performance of the EL devices with ITO modified with different binding groups (-SO2Cl, -COCl, and -PO2Cl2) of p-chlorobenzene derivatives. Finally, we examined the correlation between the change in the work function and the performance of the EL devices by the chemical modification and found that the enormous increase in ITO work function up to 0.9 eV is possible using phenylphosphoryl dichloride with a CF3-terminal group in p-position.


2012 ◽  
Vol 1402 ◽  
Author(s):  
Battulga Munkhbat ◽  
Bolormaa Gendensuren ◽  
Ganbaatar Tumenulzii ◽  
Rentsenmyadag Dashzeveg ◽  
Sarangerel Davaasambuu ◽  
...  

ABSTRACTThe work function of the indium tin oxide electrode (ITO) modified by a self-assembled monolayer (SAM), which is used as an electrode in organic electroluminescent (EL) devices, was investigated in this study. It is revealed that chemical modification of ITO with p-substituted with different terminal groups (NH2−, Cl−, and CF3−) benzoic acids as a SAMs material with carboxyl binding group is caused to increase the work function of the ITO electrode. Through a self-assembly process, the transmittance of the ITO with a SAM was not changed. The work function change of ITO with various SAM was measured by using cyclic voltammetry. Characteristics of EL devices were increased because the energy barrier was decreased in an interface between the ITO and an organic layer in the EL devices. The correlation of the work function change and the performance of the chemically modified EL devices was estimated.


2005 ◽  
Vol 484 (1-2) ◽  
pp. 272-277 ◽  
Author(s):  
Akihiko Nakasa ◽  
Mami Adachi ◽  
Eiji Suzuki ◽  
Hisanao Usami ◽  
Hitoshi Fujimatsu ◽  
...  

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