Salahaddin University-Erbil

Organic Compounds for Electronics and

Photonics Applications

Research project

Submitted to the department of chemistry in partial

fulfillment of the requirements for the degree of B.A or

BSc. In general chemistry

By

Gardoon Omar Mawlood

Kawsar Taha Muhammad

Supervised by:

Dr. Mohammed Kareem Samad

May – 2021

I support the students Gardwn Omer and Kawsar Taha

That they complete all the requirements of their research project under

the title of

Organic Compounds for Electronics and Photonics

Applications

Dr. Muhammad K. Samad

Supervisor

ABSTRACT

In recent years, through many synthetic techniques, there are growing investigation

efforts in organic electronics to enhance the conductivity, semiconducting, and light-

emitting properties of organic semiconductors, organics polymers, and hybrids

(organic-inorganic composites) instead of inorganic semiconductors such as silicon

and gallium arsenide-based semiconductors, silicon dioxide insulators, and metals

like copper and aluminum have been used as a building block of semiconducting

technology. organic electronics have many advantages over inorganic electronics

such as flexibility, performance, transparency, cost, temperature resistance (low

temperatures) over large areas on materials such as plastic or paper, may provide

unique technologies and generate new applications and form factors to address the

growing needs for pervasive computing and enhanced connectivity.

CONTENT

Page.

1. Introduction ………………………………………………………………………… 1

2. Application of organic electronics ………………………………………….….. 5

2.1. Organic vapor phase deposition (OVPD)……………………………..……………….. 6

2.2. Organic light emitting diode (OLED)………….……………………..………………….. 6

2.3. Organic Field Effect Transistor (OFET)…………………….……….………………….. 8

2.4. Organic Solar Cell (OCS)………………………………………..…………………………….. 10

3. Organic vs inorganic electronics …………………….…………………….. 11

4. Advantage of organic electronics …………………………………………. 13

5. Disadvantage of organic electronics …………………………………….. 13

6. Conclusion ………………………………………………………………………….. 15

7. Reference …………………………………………………………………………… 16

1

1. INTRODUCTION

For many years ago, some compounds are used in electronic technology such as;

inorganic silicon and gallium arsenide semiconductors, silicon dioxide insulators,

and also some metals have been used such as aluminum and copper as a backbone

of the semiconductor industry and doping process especially when they are used to

make some sensitive and important part of some electronic devices like computer

[1][6]. Nowadays, one of the most important steps in electronic rapid evolution

organic compounds (shown in figure 1) are used as organic semiconductors to make

electronic devices, they can be used in a wide range of applications having a high

potential for commercial success also to they have more effort improvements than

inorganic semiconductors [2][4][5]. The discovery and growing up of the dramatic

increase in electrical conductivity and organic electronic technology, upon doping

of semiconducting polymers, established the foundation to the field of organic

electronics. After that, the doping process of conjugated polymers and molecules,

have been extensively studied and investigated in the context of their possible

allowed application in organic electronic devices. Organic materials found their way

in many applications like light-emitting diodes, transistors, photovoltaic devices,

photo-detectors, polymer-based memories, chemical vapor sensors .It is found that

some organic materials have a good sign to be used in electronics and provide those

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properties that are not found in inorganic compounds. such as less weight than

inorganics and they are more, flexibility, also organics are relatively easy to be used

in processing as well as controllable in a wide range of electrical conductivity [1][3].

Figure 1; organic semiconductors structure

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In addition, there are many research and investigations about organic compound

materials for growing up and improving semiconducting, conducting, and emitting

of light characteristics of those organic materials and oligomers, also understanding

about hybrids such as organic-inorganic composites is one of the major factors to

improve electronics and photonics applications [5] as showed in the figure below;

Figure 2 , Performance of organic and hybrid semiconductors.

If we take a look at developing the industry, then we can easily understand that

organic materials have a great role and they are essential to the unparalleled

performance increase in semiconductors, storage, and displays at the consistently

lower costs that we see today [6]. As shown in figure 3.

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Figure 3; printed circuit using OFET

From the figure 2. We can see that how organic electronic is flexible and The

structure of OFET is shown in figure3.

Figure 4. OFET structure

There are two major classes of passive organic materials that have made possible the

current cost/performance ratio of logic chips which are photoresists and insulators

[1].

Photoresist compounds which are also known as resist, are organic compounds

with the light-emitting capability and they can be used in several processes such as

photolithography, photoengraving , chip circuitry and enable the constant shrinking

of device dimensions. According to the composition and structure, photoresists are

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classified into three classes; photopolymeric, photodecomposing,

photocrosslinking photoresist [1] [9].

Polymeric insulators have also been essential to the performance and reliability of

semiconductor devices. They were first used in the packaging of semiconductor

chips, where low-cost epoxy materials found applications as insulation for wiring in

the fabrication of printed wiring boards and as encapsulants to provide

support/protection and hence reliability for the chips [1] [8].

2. APPLICATION OF ORGANIC ELECTRONICS

Due to the technology evolution today, Organic electronics has become one of the

interested most exciting emerging areas of materials science and it is under

continuous investigation [7]. It is a highly interdisciplinary research field involving

physical, chemical science and engineers who develop organic molecules and

semiconductors with interesting and desired properties to be fit for a variety types of

applications in technical industries and electronic technology (e.g. circuitry, energy

production/storage, etc.) and organic electronic applications is also very useful for

medical applications (e.g. bioelectronics for sensors, tissue scaffolds for tissue

engineering, etc.) [10]. Here some of the most important applications of organic

electronics are mentioned:

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2.1 Organic Vapor Phase Deposition (OVPD)

It has been reported that Organic vapor phase deposition (OVDP) is a very effective

deposition technology application for high-performance thin-film organic

photovoltaic cells, transistors and light-emitting diodes. In the application of Organic

vapor phase deposition (OVPD), organic materials are evaporated by heating

process, then the vapor molecules are transported into heating chamber using carried

gas for that purpose inter gas is used as a carried gas diffusive mixing generates a

uniform and homogenous organic flux that is physisorbed onto a cooled substrate.

The wall of the reactor which is very hot, prohibited undesired vapor to be deposited

on its surface, the less time will be needed to cleaning the system. Organic vapor

phase deposition system and methods of use for simultaneous deposition of low and

high evapor ation temperature materials. And devices produced therein [11][12].

2.2 Organic Light Emitting Diode (OLED)

Organic light-emitting diodes OLED is a monolithic Device present in solid-state,

composed of more organic thin layers that are sandwiched between two other thin-

films called conductive electrodes. when an Organic light-emitting diodes (OLED)

is connected to electrical power, under the influence of an electrical field, charge

carriers (holes and electrons) moving from the electrodes of the electric source into

the thin films that made up form /organic semiconductors until they recombine in

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the emissive zone forming excitants (migrating electron from lower energy level to

higher energy level). Once formed, excited states, the relaxation will take place

(returning electrons from higher to lower energy level) by releasing light

(electroluminescence) and/or unwanted heat [13].an example of Organic light-

emitting diodes (OLED) can be seen from the figure below:

Figure 5. Organic light-emitting diodes (OLED)

Organic light-emitting diodes (OLED) is used in many application such as :

Television , Cell phone, Computer Screen , Wrist Watch , Foldable smart phones ,

Automobiles , Organic light-emitting diodes (OLED) Lenses , Data Glasses.

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2.3 Organic Field Effect Transistor (OFET)

Organic field effect transistor (OFET) is a field-effect transistor that is a channel

made of organic semiconductors. The Organic field effect transistor (OFET) can be

produced by different methods such as evaporation of small molecules in a vacuum

medium, by polymer, solution casting or solution casting of small molecules, or it

can be prepared by transferring a peeled single-crystalline organic layer onto a

substrate mechanically. The Organic field effect transistor (OFET) devices are

realized by having low-cost, huge-area electronic products and biodegradable

electronic devices. Organic field effect transistor (OFET) device has been invented

with different device geometries. The most abundant used equipment geometry is

the bottom gate with top drain and source electrodes because this geometry device

is quite similar with the same configuration to the inorganic transistor such as thin-

film silicon transistor (TFT) which the gate is made of thermally grown SiO2, and

instead of that organic polymer is used to make OFET such organic compound like

poly(methyl-methacrylate) (PMMA) as shown below:

Figure 6: PMMA structure

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In addition, it can be used as a dielectric. If we compare Organic field effect

transistor (OFET) with inorganic transistor, it has some benefits over the inorganic

transistor, such as the Organic field effect transistor (OFET) physical flexibility,

which leads to biocompatible applications, for instance in the future health care

industry of personalized biomedicines and bioelectronics.

Figure 7: Organic field effect transistor (OFET) physical flexibility

Organic field effect transistor (OFET) is used in many applications such as: Organic

field effect transistor (OFET) sensors , Bio sensors , Gas sensors , Chemical Sensors

, electronic skin , Electronic paper , E-Book , Displays embedded in smart cards ,

status displays , Organic radio frequency identification (ORFID) , Wireless

technology uses radio wave to scan or identify the product , Switching speed up to

13.56 MHz [14] [15] [16].

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2.4 Organic Solar Cell (OCS)

An organic solar cell (OSC) is also called a plastic solar cell/for now this is one of

the most concerned fields especially due to the lack of electric power, organic solar

cell (OSC) is a type of photovoltaic that uses organic electronics based on organic

semiconductors, this type of electronics concern conductive organic polymer or tiny

organic molecules, for absorption of light and transferring charge to producing

electric power from light, more specifically the sunlight based on photovoltaic

phenomena, for that purpose the photovoltaic cells must use which are polymer solar

cells. Such organic polymers that used to make photovoltaic cell are shown below:

Figure 8: Organic Solar Cell, Organic photovoltaic (OPV) Materials

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Organic photovoltaic (OPV) are particularly promising alternatives for solar-cell

generation of energy because of the abundance of their constituent elements and base

materials, their low cost, and relative ease of chemical synthesis [17][18].

Organic solar cell (OSC) is used in many applications such as: Organic solar cell car

, In satellite , Calculators ,wearable solar cell.

3. ORGANIC VS INORGANIC ELECTRONICS

- Organic electronic is a result of synthetic chemistry, in this field a very large variety

of molecules and polymers are prepared and consumed to make electronics, such as

organic semiconductors as shown below:

Figure 9: Organic semiconductors

While inorganic electronic uses inorganic semiconductors which are non-carbon

based semiconductors such as silicon, gallium, or arsenide as shown below:

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Figure 10: Gallium arsenide structure

- One of the most important advantages of organic electronics is low material

consumables because a very thin layer can be made from Organic semiconductors

that their a thickness of around 150 and 250 nanometers (nm) which are 1000 times

less thick than the human hair. However, with inorganic semiconductors it is

impossible.as shown from figure2.

- Reduction of material consumption amount (low cost) the material consumption with

one 1 g of organic material a thin film of m2 can be made. This makes organic materials

ideal for large-area applications. While the overall price with inorganic materials are

high.

- The amorphous organic semiconducting thin films are more flexible than inorganic

electronics which are very stable.

- The processers that are made from organic materials can maintain low temperature,

while inorganic processers can heated quickly.

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- Moreover, the combination of transparent substrate and electrodes (e.g. conductive

oxides) and the thin organic layers allows for transparent devices, a design not

realizable using inorganic semiconductors .

4. ADVANTAGE OF ORGANIC ELECTRONICS

1- They are biodegradable (being made from carbon).

2- This opens the door to many exciting and advanced new applications that would

be impossible using copper or silicon.

5. DISADVANTAGE OF ORGANIC ELECTRONICS

1- The carrier mobility is an important parameter to show performance criteria for

organic semiconductors, High-carrier mobility values indicate that the device

operation is fast and needs low coast for the large area also it fits with performance

meeting market demands, Organic electronics have low carrier mobility.

2- Easily affected by ionizing radiation

3- Conductive polymers have high resistance and therefore are not good conductors

of electricity.

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4- May have a shorter life of operation because of using more complex chemicals

in that field as shown below.

Figure 11: some complex organic semiconductors

5- Low optimum temperature operation windows: they cannot go as low as

inorganics, nor as high.

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6. CONCLUSION

Organic electronics is a field of opportunity and challenge, opportunity for users

such as low cost, flexibility etc , an opportunity for research; new electrical

characteristics, conduction, charge electric transfer, The organic electronics field has

made great strides over the past forty years, it deals with conductive polymers and

conductive small molecules, it has been used in many devices that are already on the

market and a multitude of prototypes in development. inorganic films and crystals that

are used in the laboratory, they replaced by hybrid, organic, or biomaterials due to their

high ability for forming, transmission, modulate and detection light in their lightweight and

flexible nanoarchitectures. The field is still needed more investigation and needs more

study, it will continue to grow such as improvements on the material side are still

needed (doping possibility).

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7. REFERENCES

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