Photoluminescence spectroscopy, often referred to as PL, is when light energy, or photons, stimulate the emission of a photon from any matter. It is a non-contact, nondestructive method of probing materials. In essence, light is directed onto a sample, where it is absorbed and where a process called photo-excitation can occur. The photo-excitation causes the material to jump to a higher electronic state, and will then release energy, (photons) as it relaxes and returns to back to a lower energy level. The emission of light or luminescence through this process is photoluminescence, PL.
Our PL optimized series of spectrophotometers are used in Fluorescence Spectrometers, Raman Spectrometers and our Custom Optical Solution Systems. These products are also making a major contribution to the development of nanomaterials, semiconductors, photovoltaics / solar cells.
By combining Raman analysis with PL detection, it is possible to characterize both the vibrational and electronic properties of materials on a single bench top platform. Combined Raman-PL systems allow confocal mapping capabilities with sub-micron spatial resolution. A wide range of excitation wavelengths is possible, from the UV to NIR, allowing control of the penetration depth into the material, and thus, control of the volume sampled.
Photoluminescence used in Fluorescence spectroscopy can provide two results: Fluorescence and Phosphorescence. The Photoluminescence quantum yield or PLQY of a molecule or material is defined as the number of photons emitted, as a fraction of the number of photons absorbed is one of the common techniques for Fluorescence Spectroscopy.
Photoluminescence is when light energy, or photons, stimulate the emission of a photon. It takes on three forms: fluorescence, phosphorescence and chemiluminescence. Fluorescence is a type of luminescence caused by photons exciting a molecule, raising it to an electronic excited state. The excited state undergoes rapid thermal energy loss to the environment through vibrations, and then a photon is emitted from the lowest-lying singlet excited state. This process of photon emission competes for other non-radiative processes including energy transfer and heat loss.
Time resolved photoluminescence (TRPL) can be performed with spectrometers and microscopes. Using Time Correlated Single Photon Counting (TCSPC) the instruments with Picosecond lasers for excitation sources has been used in the solar cell industry to monitor carrier lifetime and cell performance.