Asymmetric Cyanine NIR Fluorescence Standard for Photoluminescence Calibration
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Solution Overview
Problem
Current fluorescence standards lack suitability for the near-infrared (NIR) spectral range, particularly for calibration purposes, due to narrow structured absorption and emission bands, low fluorescence quantum yields, and instability, which limits their use in determining spectral sensitivity, fluorescence quantum yield, and long-term stability of photoluminescence measuring systems.
Innovation Solution
A cyanine compound with broad, smooth, and unstructured absorption and emission spectra, high fluorescence quantum yield, and moderate emission anisotropy, suitable for use in both solution and solid matrices, is developed to serve as a fluorescence standard for calibrating photoluminescence measuring systems across the NIR spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluorescence standards are used for NIR calibration, then measurement coverage is limited, but the standards exhibit narrow structured absorption and emission bands, low fluorescence quantum yields, and poor stability
Solution Approach 1:
The patent modifies the molecular structure of cyanine compounds by changing parameters such as substituting aromatic rings with heteroaromatic rings (e.g., pyridine, pyrimidine, triazine), adjusting alkyl chain lengths, and modifying the conjugation system. These parameter changes result in broader, smoother spectra, higher fluorescence quantum yields (≥20%), and improved stability in the NIR range, resolving the contradiction between reliability and measurement precision.
Solution Approach 2:
The invention creates composite fluorescent standards by combining cyanine compounds with various matrices including polymers (PMMA, polystyrene), glass, and liquid solvents. This composite approach allows the standard to maintain high performance across different measurement conditions while achieving the desired spectral characteristics and stability.
2Ease of operation
If existing NIR fluorescence standards are used, then calibration can be performed, but the standards show structured emission spectra with steep edges that cause measurement uncertainty
Solution Approach 1:
The patent systematically modifies the spectral parameters of cyanine compounds by adjusting the conjugation length, substituting aromatic units, and modifying side chains. These changes produce emission spectra with broader bandwidths, smoother profiles, and reduced steepness at spectral edges, thereby reducing measurement uncertainty while maintaining ease of calibration operation.
3Measurement precision
If conventional standards are used for quantum yield determination, then measurements can be taken, but the standards have low fluorescence quantum yields and poor photostability
Solution Approach 1:
The invention optimizes the molecular parameters of cyanine compounds, particularly the heteroatom substitution and conjugation system, to simultaneously achieve high fluorescence quantum yields (≥20%) and excellent photostability. The modified molecular structure reduces non-radiative decay pathways while maintaining high radiative transition probabilities, resolving the contradiction between measurement precision and reliability.
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
The cyanine compound provides a reliable and stable fluorescence standard for determining emission and excitation correction functions, fluorescence quantum yield, and linearity range, enabling accurate calibration and performance checking of photoluminescence measuring systems in the NIR range, with improved stability and reduced measurement uncertainty.
Implementation Method 1
a cyanine compound as a fluorescence standard in the near-infrared spectral range (NIR)... for determining the relative spectral sensitivity of photoluminescence measuring systems
Implementation Method 2
absorption and emission spectra, which are unusually broad, smooth and unstructured for NIR fluorophores
Data Source
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AI summary
Use of asymmetric cyanine compounds (I) as near-infra red spectral fluorescence standard, is claimed. Use of asymmetric cyanine compounds of formula (I) as near-infra red spectral fluorescence standard, is claimed. B1, B2 : H, methyl, ethyl, phenyl, naphthyl, benzoxazole, benzimidazole, benzothiazole or indole residue; X-X3 : methyl, ethyl or phenyl; Z : N or C; and A ->anion, where one or more hydrogen in (I) and the aforementioned radicals are optionally substituted. An independent claim is included for a kit for the traceable calibration of a photoluminescence system, preferably a fluorescence measurement system, comprising (I) as a fluorescent standard and a spectrally corrected fluorescence spectrum of the fluorescence standards in tabular form, in computer readable form and/or an indication of a website on which the corrected fluorescence spectrum is present. [Image].