OLED vs. Inorganic LED: Key Differences Explained

This article highlights the key differences between Organic LEDs (OLEDs) and Inorganic LEDs, exploring their respective advantages and disadvantages. We’ll delve into the fundamentals, types, and applications of OLED technology.

Organic LED (OLED) Explained

Introduction

OLED stands for Organic Light Emitting Diode. OLEDs function based on the principle of electroluminescence, where certain organic materials emit light when an electric current passes through them.

In its simplest form, a monolithic OLED consists of two thin organic layers:

• ETL: Electron Transport Layer
• HTL: Hole Transport Layer

These layers are sandwiched between two thin film electrodes: an Anode and a Cathode. The Anode is often made with an ITO (Indium Tin Oxide) coating, while the Cathode is made with a thin coating of MgAg (Magnesium-Silver alloy).

For ETL materials, organic substances like Tris (Tris(8-hydroxyquinolinato)aluminium) with a glass transition temperature of around 174°C are favored. TPD (N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine) and α-NPD (N,N′-Di(naphthalen-1-yl)-N,N′-diphenyl-benzidine) are commonly used as HTL materials.

OLED Structure

Figure 1: A typical OLED structure includes the Cathode, Emissive Layer, Conductive Layer, Anode, and Substrate.

Advantages of Organic LED (OLED)

Compared to inorganic components, OLEDs offer several benefits:

• Thin and Lightweight: OLEDs are thinner (< 300 nm), lighter, and more flexible.
• Cost-Effective: Manufacturing costs are generally lower.
• Superior Picture Quality: They deliver brighter and clearer images.
• Low Power Consumption: OLEDs consume significantly less power.
• Easy to Manufacture: Production is simpler, enabling larger sizes.
• Wide Viewing Angle: OLEDs provide a large field of view.
• Versatile Printing: They can be printed on various surfaces.
• High Luminous Efficiency: They have excellent luminous power efficiency.
• Fast Response Time: Their rapid response time is ideal for animation and entertainment.
• Flexible Displays: Being polymeric, they can be grown on flexible surfaces.
• Color Tuning: They offer color tuning flexibility for full-color displays.

Disadvantages of Organic LED (OLED)

OLEDs also have some drawbacks:

• Shorter Lifespan: Their lifespan is shorter compared to other display types. White, Red, and Green OLEDs offer a lifespan of about 5 to 25 years, while Blue OLEDs last around 1.6 years.
• Higher Cost: They are more expensive compared to LCDs.
• Susceptibility to Water: They are easily damaged by water.
• Poor Sunlight Performance: OLED screens perform worse than LCDs in direct sunlight.
• Luminance Degradation: They experience overall luminance degradation over time.
• Limited Availability: Their market availability is limited.

Organic LED vs. Inorganic LED: Key Differences

The following table highlights the main differences between Organic and Inorganic LEDs: