Absolute Brightness Determination for Luminescent Particles
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Solution Overview
Problem
Current methods for determining the brightness of luminescent particles are limited by their inability to provide absolute, device-independent values, leading to relative intensity scales with high uncertainties, especially due to environmental sensitivity and particle inhomogeneities, which complicates the development and comparison of particle standards in various applications.
Innovation Solution
A method that determines the absolute brightness of luminescent particles by measuring their photoluminescence quantum yield and absorption cross section, using ensemble measurements and tracing these values back to fundamental physical parameters, allowing for the calculation of brightness per particle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If relative brightness values are determined using flow cytometry or fluorescence microscopy, then measurements can be performed on individual particles, but the values are not instrument-independent and have high uncertainties
Solution Approach 1:
The patent segments the measurement approach by separating the determination of absolute brightness from relative brightness measurements. It uses ensemble measurements to determine fundamental parameters (quantum yield, absorption cross-section) that can then be used to calculate absolute brightness, avoiding the need for complex instrument-specific calibration procedures while achieving instrument-independent values
Solution Approach 2:
The patent introduces fundamental physical parameters (photoluminescence quantum yield and absorption cross-section) as intermediaries between the measurement system and the brightness value. These parameters serve as universal mediators that enable conversion to absolute brightness without instrument-specific calibration, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If fluorescence quantum yields are determined for particle suspensions, then optical properties can be characterized, but absolute brightness values cannot be obtained due to particle inhomogeneities
Solution Approach 1:
The patent extracts the determination of fundamental parameters (quantum yield and absorption cross-section) from the problematic direct measurement of individual particle brightness. By measuring ensemble properties and extracting these fundamental parameters, the method obtains absolute brightness values that are not affected by particle inhomogeneities, as the fundamental parameters represent average properties of the particle system
Solution Approach 2:
The patent changes the measurement parameters from direct brightness measurement to measurement of fundamental parameters (quantum yield and absorption cross-section). This parameter transformation allows the calculation of absolute brightness from ensemble measurements, bypassing the issue of particle inhomogeneities that plague direct individual particle measurements
3Adaptability or versatility
If the MESF system is used for calibration, then relative quantification can be performed, but a true absolute intensity scale cannot be established
Solution Approach 1:
The patent fundamentally changes the calibration parameters from relative MESF values to absolute physical parameters (quantum yield and absorption cross-section). This parameter transformation enables the establishment of an absolute intensity scale traceable to fundamental physical quantities, while maintaining the versatility of particle-based calibration systems across different applications
Solution Approach 2:
The patent replaces the mechanical/instrument-specific MESF calibration system with a physics-based absolute measurement system. By substituting the relative calibration approach with measurements of fundamental photophysical parameters, the method establishes an absolute intensity scale that is independent of specific instrument characteristics while maintaining broad applicability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the establishment of a traceable intensity scale for fluorescence methods, facilitating direct comparison and standardization of luminescent particles, reducing measurement uncertainties and enabling the use of particles as reliable reference standards across different applications.
Implementation Method 1
determining an absolute photoluminescence quantum yield of the particle suspension in the sample volume
Implementation Method 2
determining an absorption cross section of the particles in the sample volume
Data Source
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AI summary
A method for determining the (absolute) brightness of a luminescent particle is proposed, which is traceable to actual physical quantities. For this purpose, a sample volume containing a particle suspension comprising an ensemble of luminescent particles is provided. The absolute photoluminescence quantum yield of the particle suspension in the sample volume and the absorption cross-section of the particle suspension in the sample volume are determined. The absolute brightness of a single particle is determined based on the measured absolute photoluminescence quantum yield, the absorption cross-section, and the number of particles in the sample volume.