Direct Quantum Yield Measurements of Unknown Luminescent Samples

Quantum yield is one of the most important parameters that characterize photoluminescence of materials. Photoluminescence Quantum Yield (PLQY) measurements are critical for a broad range of applications, including new material development, photovoltaics and the development of new fluorescence probes. With thousands of PLQY citations  around the world, HORIBA has long been recognized for its superior quality of PLQY performance for the most demanding applications.

The QuantaPhi-2 is a new internal photoluminescence quantum yield (PLQY) and CIE measurement accessory for compatible HORIBA fluorescence spectrometers. Compatible HORIBA fluorescence systems include the following:

• Fluorolog-QM modular research spectrofluorometer
• Nanolog modular research spectrofluorometer
• FluoroMax Plus bench top research spectrofluorometer

This sample tray accessory includes an all-reflective sphere into which a sample is placed. The measurement of the sample, and of a non-fluorescent blank, allows for the direct measurement of the quantum yield of a solid, powder or solution sample.

Combined with our highest sensitivity and flexible spectrofluorometers, and their simple-to-use, dedicated QY and colorimetry software, the QuantaPhi-2 provides a high quality, simple and absolute PLQY solution. The quantum yield of a molecule or material is defined as the number of photons emitted as a fraction of the number of photons absorbed. This characteristic property of a fluorophore or fluorescent molecule, is very important for understanding molecular behavior and optimization for many key materials.

Materials and Applications for which PLQY are Important Parameters

• Photovoltaics (PV) and solar cells
• Novel nanomaterials
• Nanoparticles
• Quantum dots
• Graphene/single walled carbon nanotubes
• New fluorescent probes
• Biomarkers and biosensors
• Lighting and display materials (OLED, LED and phosphors)
• Thin films and coatings
• Light emitting devices
• Cured/doped polymers, gels, hydrogels
• Paints, coatings,
• Rare earth materials

Characterize Light-emitting Devices

Electroluminescent quantum yield (ELQY) measurements of light-emitting devices, such as LEDs, OLEDs, and other luminescent sources, are fully accommodated by the QuantaPhi-2. Electrical connections to the device are facilitated by a dedicated wiring port in the bottom loading drawer, allowing a customer to feed wires to their custom modified sample cup holder. Shown below are the CIE values and total luminous intensity plots of a simple LED measured using the QuantaPhi-2.

^{HORIBA FluorEssence software interface for the Fluoromax and Nanolog spectrofluorometers.}

Software That Makes PLQY Simple and Accurate

The QuantaPhi-2 integrating sphere accessory is compatible with a number of HORIBA fluorescence spectrometers, and all of these systems have a PLQY App, that simplifies the process of acquiring an accurate QY value for an unknown sample.

^{FelixFL software on the Fluorolog-QM modular research spectrofluorometer incorporates a quantum yield calculator which, when coupled with an integrating sphere, allows you to calculate the quantum yield with ease.}