- Quantum Efficiency
- PV Field
- Luminescence Quantum Efficiency (EQE)/ Quantum Yield (QY) Measurement System
LED Photo-Luminescence Quantum Yield Measurement System
Enli Tech LQ-100X series provide the best solutions for measuring LED and various light emitting materials. With 50 mm or 100 mm PTEF integrating sphere collecting all the light of LED, the LQ-100X series can instantaneously measure LEDs’Lumens (lm), Power (W), External Quantum Efficiency (EQE), Emission Spectrum, CIE, IV curve and Lifetime, etc. LQ-100X series can be applied to a variety of applications, such as the PLQY of light emitting device to help researchers analyze the device characterization and quality.
◆ EL Probe System：
two exclusive spring probe stage with magnetic bases provides flexibility to adjust the sample position.
◆ High-Power Excitation Source：
368 nm high-power LED excitation source (Multiple lasers selectable: 365 nm, 405 nm, 505 nm, 530 nm, 617 nm, 730 nm, and user can choose other four excitaton source maximum)
◆ SOLARTM Measurement Kit (Option) :
can measure Solar EL and PL spectrum.
◆ Ultra-low Light Intensity Detector (Option) :
can measure the ultra-low light intensity, below 0.1 cd/m2 luminance, and get the perfect EQE curve.
|Luminescence Measurement System||
a. Equipped with PTFE integrating sphere system: conform to commercial LED standard
b. Can measure Lumens (lm) and Power (W)
c. The lowest brightness for LED EQE: 0.1 cd/m2 (min)
d. Can adjust the exposure time of spectrometer automatically and enhance the measurement speed
e. Customized test fixtures for LED EQE measurement
f. Compatible with different source meters
g. Manual multiplexer. (option)
h. Can measure PLQY of light-emitting materials. (option)
i. SOLAR-ELTM measurement kit: can measure EL and PL of solar cells. (option)
|100 mm integrating sphere||
a. 100 mm Integrating Sphere (outer dimension 4 inches, inner diameter 3.3 inches)
b. Aluminum alloy shell
c. PTFE high reflective material (reflectance can cover 200 nm-2500 nm)
d. Reflectance ≧96±2 % (380 nm-1100 nm)
|Multichannel Spectroscope (Spectrometer)||
a. # Pixels, pitch μm: 2048, 14 x 200 μm
b. Sensitivity (V/(lx-s)): 1300
c. QE(%)@peak: 74 %
d. Signal/Noise: 600:1
e. Dynamic Range: 5,000
f. Frequency: 2 MHz
g. Wavelength range: 300 nm-1100 nm
h. Wavelength Resolution: 0.35 nm-1 nm
i. Interface: USB
|Vertical optical path and probe system||
a. Two soft needles with magnetic bases
b. 4-wire Kelvin Probe with banana connector, can cooperate with the source meter
c. Source meter connector: V+V-I+I- banana connector (Male)
d. Sample size: smaller than 30 mm x 30 mm
b. LCD monitor
|EL measurement software||
a. Lumens: lm
b. Luminous Intensity: cd
c. Luminance: cd/m2
d. Color Coordinate: (x,y), (u',v')
e. Correlated Color Temperature
f. Peak Wavelength: Wp
g. Purity: %
h. Lum./W: Efficiency
i. LIV scan curve and diagram output
k. Lifetime (intensity vs time) measurement
l. Compatible with Keithley 2400, 2602 source meter and Keysight B2901 source meter
a. Low brightness photoelectric detection channel with single photon counting capability, accuracy: <0.1 cd/m2
b. Cathode luminescence flux sensing capability: 200 uA/lm, radiation response capability: 77 mA/W
c. Anode luminescence flux sensing capability: 400 uA/lm, 1.5 x 105 A/W; response time: 0.57 ns
d. With automatic mechanical shutter, avoid over-damaging the sensing electrode
e. Built-in Transimpedance Amplifier
f. USB interface, 14 bits signal output
|Sample holder||Customized according to the device|
- Measuring PLQY and EL of light-emitting materials
- High-power LED excitation source
- Full angle luminous flux measurement
- Full spectrum measurement: 350 nm-1000 nm
- High-sensitivity measurement: 0.1 cd/㎡(min.)
- Combine with the source meter to achieve automatic full spectrum scanning and measuring under different voltage or current
- Can integrate the following functions：
● Continuous current scanning mode
● Continuous voltage scanning mode
● Lifetime measurement
● PLQY measurement
What is PL?
Photoluminescence is light emission from any form of matter after the absorption of photons. Theoretically, light is directed onto the surface of materials where it is absorbed and then a process called photo-excitation will occur. The materials jump to a higher energy level, and will release energy, then it will return to a lower energy level. The luminescence through this process is photoluminescence or so-called PL.
What is PLQY?
Photo-Luminescence Quantum Yield (PLQY): When a fluorophore absorbs a photon of light, an energetically excited state is formed. The fate of this species is varied, depending upon the exact nature of the fluorophore and its surroundings, but the result is deactivation (loss of energy) and return to the ground state. The photoluminescence quantum yield is the ratio of photons absorbed to photons emitted through photoluminescence. In other word the quantum yield gives the probability of the excited state being deactivated by photoluminescence rather than by other, non-radiative mechanism.
PLQY= Photon emitted / Photon absorbed.
The minimum measurement value can be 0.1%
◆ Electroluminescence (EL) of Perovskite LEDs
The development of perovskite LED efficiency is rapidly progressing at present, but the most challenging task which most researchers have been facing is how to get the accurate PLQY of perovskite LEDs.
Here are the characteristics of Perovskite LED：
Low luminance, and decay very fast
● < 50,000 cd/m2
● LQE-100 series provide fast measurement speed for users getting high efficiency.
● < 50,000 cd/m2
● LQE-100 series can record and calculate the error of the photoluminescence spectrum.
● cd/m2 EQE, the deviation value is higher
● Ultra-low light intensity detector (optional): can measuring the ultra-low light intensity, below 0.1 cd/m2 luminance, and get the perfect EQE curve.
High-efficiency NIR extension capability：
● The emission wavelength cannot be included in luminosity function, and is not able to estimate its efficiency by Lumens(lm) and Luminance(cd/m2)
LQE-100 series Total solutions：
LQE-100 series provide high-power LED excitation source to measure the various light emitting materials. LQE-100 series have various analysis functions: PLQY, EQE, Irradiance, Luminance, CIE, etc, which can help researchers measure samples instantaneously and precisely.
EL Spectrum of Perovskite LEDs
|Luminance||Per point Measuring EL spectrum of perovskite LEDs|
|High-luminance||>6000cd/m2||< 50 ms|
|Ultra low-luminance||< 10 cd/m2||<0.5 sec|
◆Record function of Aging Test for LED device
Use constant current and voltage to measure the variation of luminance and efficiency in time
● V-t Curve：The voltage-time curve under constant-current
● J-t Curve：The current density-time curve under constant voltage
● I_Eff-t Curve：Current efficiency-time curve
● P_Eff-t Curve：Power efficiency-time curve
● EQE-t Curve：The external quantum efficiency time curve
● Recording and monitoring the spectrum variation
● Repeatability of OLED：non-repeatability<0.2%
Non-repeatability<0.2% (under ≧1,000 cd/m2)
Latest publications referencing PLQY EL
Xiaolei Yang, Xingwang Zhang, Jinxiang Deng, Zema Chu, Qi Jiang, Junhua Meng, Pengyang Wang, Liuqi Zhang, Zhigang Yin and Jingbi You
Nature Communications, Volume 9, Article number: 570