Standards Development

Scope

This part of IEC 62607 establishes a standardized method to determine the key control characteristics

 photoluminescence quantum yieldfor luminescent nanomaterials in transparent matrices by

 absorption and photoluminescence spectroscopy.

The photoluminescence quantum yield is derived by using a calibrated spectrophotometer in combination with a spectrofluorometer.

– Photoluminescence quantum yield is defined as the number of emitted photons per number of absorbed photons of different types of molecular and nanocrystalline luminophores (emitters) in transparent matrices like solutions/dispersions using relative optical methods.

– The method is applicable for luminescent nanomaterials which includes nano-objects such as spherical and rod-shaped quantum dots, nanophosphors, nanofibers, nanocrystals, nano platelets and structures containing these materials that are small enough not to introduce light scattering or for which the refractive index of dispersed nanomaterial and matrix closely match, thereby preventing or at least strongly reducing light scattering also for larger nano-object sizes.

– In principle, this method is also suitable for the determination of the photoluminescence quantum yield of molecular luminophores and luminescent nanoparticles in transparent solid matrices, meeting the previously stated size restrictions. For these systems, the accurate relative determination of the photoluminescence quantum yield can require the use of polarizers as luminophores can be susceptible to polarization effects in solid matrices.

– This test method is not suited for the determination of the photoluminescence quantum yield of scattering dispersions of luminescent nanomaterials such as semiconductor quantum rods with a large aspect ratio. Measurement of the photoluminescence quantum yield of scattering luminophore systems such as dispersions of larger nano-objects or powders of luminescent nanoparticles and differently sized phosphors requires the usage of integrating sphere spectroscopy.

– Fields of application include the determination of the fluorescence quantum yields of transparent dispersions of semiconductor quantum dots or other nanoobjects.