STUDY OF FABRICATION OF ORGANIC LIGHT-EMITTING DIODE DEVICE USING TRIPHENYLAMINE DERIVATIVE COMPOUND AND POLYANILINE AS HOLE TRANSPORTING MATERIAL

• Main Author: REZA (NIM : 20514060), MUHAMMAD
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23312
• Institution: Institut Teknologi Bandung

Until now, the use of conventional lighting sources such as incandescent and fluorescent lamps are still the main choice because of their ease of availability. However, the low efficiency of these sources leads to the problem of excessive energy consumption. One example of efficient lighting source is Light-Emitting Diode (LED). LED is a solid light-producing devices composed by thin films of semiconductor material between two electrodes. Thanks to its efficient properties, people use LED as a display on an electronic devices. The emitted color from the LED is more diverse, depending on the material used. To get a flexible screen, researchers developed an organic compound-based LED called Organic Light-Emitting Diode (OLED). Another advantages of the OLED among others are produce more vivid color and the fabrication process is relatively easy. Organic semiconductor materials which is commonly used in OLED devices as the active material can be either a small molecule that has a system of conjugated double bonds or polymers. OLED which is fabricated in this study had a Schottky-type diode where there is direct contact between the metal and the organic semiconductor material. The significant difference between work function of metal and energy level of the semiconductor material is resulting to the high value of barrier height (&#934;B) and ideality factor (&#951;) in this type of diode (&#934;B = 0.50 eV and &#951; = 4 – 5). This study has been conducted to determine the optimum conditions for fabricating OLED using triphenylamine-based small molecule (TPA) and polyaniline (PANI) as hole transporting material (HTM). In this study, the optimum conditions for fabricating OLED is the use of a solution casting method of solution of 1% weight of PANI emeraldine base form (PANI EB) in N-methyl pirolidone (NMP) to deposit the HTM layer. This method can produce a quite homogenous layer and has the characteristics of plastic. The second optimum conditions is the use of HCl 1 M as dopants for PANI EB. There is a direct proportional relationship between the concentration of HCl used, the presence of polaron species (C-N.+) in the chain of PANI emeraldine salt form (PANI ES), and conductivity values of obtained PANI ES. Polaron species is indicated by the peak in the wavenumber of 1244 cm-1 in the FTIR spectrum and 1320 cm-1 in the Raman spectrum. When the peak intensity increases, the value of the conductivity of PANI ES is also increasing. The obtained maximum conductivity is 3.18 x 10-2 S/cm. In addition, the ratio of peak intensity at wavenumber of 1244 cm-1 to 1300 cm-1 in the FTIR spectrum for this v <br /> <br /> <br /> concentration is the highest among other concentration (0.930). The optimum conditions will produce OLED with Schottky-type diode characters (&#934;B = 0.498 eV and &#951; = 7.71) and the quite low operating voltage (0.5 V). Leakage currents is detected on the OLED using TPA-based small molecule as HTM. This is due to by the silver paste which is deposited using a screen printing method can dissolve the thin film that has been deposited before and forming a direct contact between the two electrodes.