Near-Infrared Phosphor Measurement

Introduction

Near-infrared fluorescence labels are currently attracting the attention of the scientific community due to their wide range of biological applications. These labels are ideal for biological studies since biomolecules absorb very little in the near-infrared region. NIR fluorescence labels have shown no adverse effects in vivo and are highly stable.

This application note illustrates how the FP-8700 is used to obtain fluorescence spectra and quantum yields of phosphors in the near-infrared spectral region.

Experimental

Measurement Conditions

Excitation		Fluorescence
Emission Wavelength	883 nm	Excitation Wavelength	600 nm
Emission Bandwidth	10 nm	Excitation Bandwidth	10 nm
Excitation Bandwidth	10 nm	Emission Bandwidth	10 nm
Scan Speed	500 nm/min	Scan Speed	500 nm/min
Response Time	0.5 sec	Response Time	0.5 sec
Data Interval	0.2 nm	Data Interval	0.2 nm
Sensitivity	600 V	Sensitivity	600 V

Keywords

FP-8700, ESC-842 Calibrated WI light source, ILF-890 Integrating sphere, FPA-810 Powder measurement block, PSH-101 Powder cell, Fluorescence, Near-infrared, Quantum yield

Results

The excitation spectra of YVO₄:Nd³⁺ and YVO₄:Nd³⁺, Yb³⁺ are shown in Figure 1 and the peaks are labeled with their corresponding excited state transitions from the ground state of Nd³⁺ (⁴I_9/2).

Figure 1. Excitation spectra of YVO4:Nd3+ (blue) and YVO4:Nd3+, Yb3+ (red).

The fluorescence spectra of YVO₄:Nd³⁺ and YVO₄:Nd³⁺, Yb³⁺ are shown in Figure 2 and the peaks are labeled with their corresponding transition states from the excited states of Nd³⁺ (⁴F_3/2) and Yb³⁺ (²F_5/2).

Figure 2. Fluorescence spectra of YVO4:Nd3+ (blue) and YVO4:Nd3+, Yb3+ (red).

The quantum yields of both YVO₄:Nd³⁺ and YVO₄:Nd³⁺, Yb³⁺ were calculated and shown in Table 1.

Table 1. Quantum yield results.

	Absorbance (%)	External Quantum Yield	Internal Quantum Yield
YVO₄:Nd³⁺	9.0	2.5	28.5
YVO₄:Nd³⁺, Yb³⁺	21.0	12.4	59.1

Conclusion

This application note uses a FP-8700 to obtain fluorescence measurements in the NIR spectral region. This data is used to characterize near-infrared phosphors, which can later be used as fluorescent labels in biological studies.

Required Products and Software

FP-8700 Spectrofluorometer
FPA-810 Powder Sample Cell Block
PSH-101 Powder Sample Cell
ESC-842 Calibrated WI Light Source
ILF-835 100 mm dia. Integrating Sphere
KBr Plate Sample Holder
FWQE-880 Quantum Yield Calculation program

About the Author

Leah Pandiscia received her PhD from Drexel University where she studied Biophysical Chemistry. She is a Spectroscopy Applications Scientist.

JASCO