Quantum Efficiency Measurement of Lamp Phosphors in Accordance with Radiometric Standards

Abstract

To measure the quantum efficiencies of lamp phosphors, a JCSS (Japan Calibration Service System) traceable measurement method that uses a polychromator, with improved optical design to reduce stray light, and an integrating sphere has been developed. To verify the measurement accuracy of this method, a monochromator, which has a 0 : 45 x incident optical system, was used. The BRDF (Bidirectional reflectance Distribution Function) of the phosphor was measured by a goniophotometer. A comparison was made between these JCSS traceable measuring devices on the 260 nm to 400 nm wavelength characteristics of the internal quantum efficiency of the blue phosphor BAM (BaMgAl 10 O 17 : Eu 2 ), which has excitation characteristics up to 400 nm. The results agreed within 4% of the difference of the measured values. This is a good agreement considering that it was a composite measure and that the uncertainty of the spectral irradiance standard in the spectral region is lower than 3%. It has also been established that the proposed method using a polychromator and an integrating sphere shows sufficient measurement accuracy.

Anomalous fluorescence of the spherical carbon nitride nanostructures

“…Wavelengths of the exciting lasers were 405 nm, 532 nm, and 633 nm. Details of the method can be found elsewhere [15,16]. Briefly, the fluorescence quantum yield, which is the number of emitted photons (N em ) per number of absorbed photons (N abs ), presents a direct measure of the efficiency of the conversion of absorbed into emitted light…”

Narrow-Band Green-Emitting Phosphor Ba2LiSi7AlN12:Eu2+ with High Thermal Stability Discovered by a Single Particle Diagnosis Approach

“…The particle’s absorption was obtained by subtracting the spectrum of the particle and BaSO 4 from the reflection spectrum of BaSO 4 (without the particle). The internal QE was obtained by the following equation: where E­(λ)/ h ν, R­(λ)/ h ν, and P­(λ)/ h ν are the numbers of photons in the excitation, reflectance, and emission spectra of the phosphor, respectively . The decay property was measured with a time-controlled single photon counting (TCSPC) technique.…”

Thermal Relaxation Spectra for Evaluating Luminescence Quantum Efficiency of CASN:Eu2+ Measured by Balanced-Detection Sagnac-Interferometer Photothermal Deflection Spectroscopy

“…In this paper, we have implemented balanced detection into SIPDS and achieved fourfold improvement in S/N compared with SIPDS without balanced detection. We have applied this system to the measurement of photothermal excitation spectrum (PTES) of Eu 2+ -doped CaAlSiN 3 phosphors [13,14] and estimated the luminescence quantum efficiency solely from comparison with the photoluminescence excitation spectrum (PLES), in good agreement with that measured independently by the absolute quantum efficiency measurement system using integrating sphere [15].…”

“…Thus, luminescence photon flux density is given by: (15) and photon flux which is converted to heat and emitted from the sample surface is:…”