Basic Principle

Electroluminescence (EL) is a physical phenomenon where an electric field created by voltage applied across two electrodes excites electrons to collide with luminescent centers, causing electrons to jump between energy levels, change, and combine, resulting in luminescence. Electroluminescent products are known for their high luminous efficiency, long device life, fast response speed, good viewing angle characteristics, strong chromaticity, low cost, flexibility, and wide application prospects in displays and lighting. The performance of electroluminescent products is mainly determined by electroluminescent devices, such as OLEDs and QLEDs. These devices typically consist of five layers: a cathode, an electron transport layer, an emissive layer, a hole transport layer, and an anode. The material of the emissive layer is called the electroluminescent material, with organic molecular materials in OLED devices and quantum dot materials in QLED devices.

Electroluminescent Device Structure

The external quantum efficiency (EQE) of an electroluminescent device is one of the key parameters determining the luminous efficacy of the device after packaging and is crucial for the commercialization of electroluminescent devices. It reflects the efficiency of converting electrical energy into light, indicating the utilization rate of input power. Higher luminous efficiency means lower thermal loss and higher energy utilization. In the research of electroluminescent devices, the corresponding parameter is the external quantum efficiency (EQE).
Common EQE Measurement Methods
Luminance Meter Method: Measures the luminance in the normal direction using a luminance meter and calculates the device's EQE based on the standard Lambertian distribution theory. This method has significant drawbacks as the Lambertian distribution of actual devices is not always standard, leading to inaccurate theoretical calculations.

Difference Between Photometric Distribution Test Values and Lambertian Predicted Values

Integrating Sphere Method: Collects the total luminous flux of the device and calculates the EQE. There are two measurement schemes: the 2π method, which measures only the forward flux by placing the device on the sphere wall, and the 4π method, which measures the total flux by placing the device inside the sphere.

Integrating Sphere EQE Test Results Example: OLED electroluminescent devices in four colors

Typical Applications

● Inorganic/Organic Electroluminescence

● Molecular Thin Film EL Devices

● AIE (Aggregation-Induced Emission) Materials

● Quantum Dot Light-Emitting Diodes (QLED), Organic Light-Emitting Diodes (OLED), Light-Emitting Diodes (LED), Perovskite Light-Emitting Diodes (PeLED), and other types of electroluminescent devices.

Accessories

Electroluminescence Sample Fixture Case Display

● LS-EQE-AS-SZPT01
The LS-EQE-AS-SZPT01 fixture has an overall width of 62 mm, length of 70 mm, and thickness of 23.2 mm. The contact point is replaced by a spring form to increase the contact area. The sample tested is a perovskite chip with a luminescent area of 2 mm * 2 mm. The outer glass encapsulation of the sample chip is 20 mm * 15 mm, with six electrodes. The leftmost electrode is the positive (or negative) electrode, and the others are negative (or positive) electrodes. The dedicated circuit board lights up the chip sample to be tested. The upper part of the fixture has two hole structures for fixation, used to install in the electroluminescent quantum efficiency system for testing.

This fixture is mainly for perovskite materials and can be used in the fields of photovoltaics, semiconductor devices, photocatalysis, and other electronic devices such as sensors and field-effect transistors (FETs).

● LS-EQE-AS-SZPT02
The LS-EQE-AS-SZPT02 fixture has an overall height of 70.8 mm, with a base diameter of 70 mm and height of 10 mm. The fixture has a screw on the upper part, which can be rotated to adjust the height of the chip sample to be tested, meeting different height requirements. The chip sample tested with this fixture is the same perovskite chip as in the LS-EQE-AS-SZPT01, with a luminescent area of 2 mm * 2 mm and outer glass encapsulation of 20 mm * 15 mm, with six electrodes. The leftmost electrode is the positive (or negative) electrode, and the others are negative (or positive) electrodes. The dedicated circuit board lights up the chip sample to be tested. This fixture is used for vertical measurement in the electroluminescent quantum efficiency system.

This fixture is mainly for perovskite materials and can be used in the fields of photovoltaics, semiconductor devices, photocatalysis, and other electronic devices such as sensors and field-effect transistors (FETs).

● LS-EQE-AS-SUDA01
The LS-EQE-AS-SUDA01 fixture has an overall width of 67 mm, length of 70 mm, and thickness of 23.2 mm. The contact point is replaced by a top pin form and the circuit board has been replaced. This fixture tests OLED organic material chips. The outer glass encapsulation of the sample chip is 32.90 mm * 32.90 mm, with a luminescent area of 16.4 * 16.4 mm and eight electrodes. The dedicated circuit board lights up the chip to be tested. The upper part of the fixture has two hole structures for fixation, used to install in the electroluminescent quantum efficiency system for testing.

This fixture is mainly for OLED materials and can be used in fields such as mobile devices, automotive displays, digital advertising, medical devices, and aerospace.