PL / Steady-State & Time-Resolved Photoluminescence Spectroscopy

Fluorescence occurs when an orbital electron of a molecule, atom, crystal or nanostructure, relaxes to its ground state by emitting a photon from an excited singlet state:

Excitation: So + hv → S1

Fluorescence: S1 → So + hv

Relaxation from S1 can occur through interaction with a second molecule/component through fluorescence quenching. In most cases, the emitted light has a longer wavelength, therefore lower energy, than the absorbed radiation (Stokes shift). Molecules/materials that are excited through light absorption or via a different process (e.g. as the product of a reaction) can transfer energy to a second “sensitized” molecule/material, which is converted to its excited state and then fluoresce.

The phenomenon of fluorescence quenching can be examined by time-resolved measurements (TCSPC) in order to distinguish static and dynamic quenching. Further, with TCSPC it is easier to study charge-transfer phenomena from an electron donor to an acceptor material, because the emission quenched states possess different lifetime. The environment of the molecule/material affects both the energy level and the lifetime of the excited state and monitoring these interactions gives essential information about the state of the molecule/material.

μ-PLpower dependence measurement on quantum dot (QD) the excitonic and biexcitonic emission can be easily identified. The FWHM can provide information about the quality the a QD and the distance between the Excitonic and Biexcitonic emission gives information about the binding energy between these two.

Angle-resolved polariton photoluminescence at room temperature conditions shows from the anti-crossing point of the exciton level (dashed line) to exhibit a Rabi splitting as obtained by the simulated lower- and upper-polariton branches (solid curves).

Tool

Steady-state and time resolved Photoluminescence multi-component system

Excitation

CW lasers: 325nm, 408nm, 655nn, 780nm and 910nm
Pulsed: 266nm, 360-450nm, 710-920nm

Detection

200-2200 nm

Time resolution

100ps or 200 (depending on detector TR-PL)

Sample temperature range

15K-300K

Sampling modules

Solid/Film

Additional tools

Micro-PL (Temperature range:77K-300K, excitation source: cw and pulsed laser from 266nm to 910nm, detection: 250nm-1100nm)
Power and Temperature dependence PL
k-space and real imaging measurements and analysis
micro-PL mapping for nanostructures
Polarization measurements

Applications

Optoelectronic materials properties
Calculation of impurities and alloys concentration
Single nanostructure characterization like one quantum dot
Quantum Cryptography

Additional Information

Dr. Maria Androulidaki, pyrhnas@physics.uoc.gr

Tool

Steady-state Photoluminescence and TCSPC system Horiba / Jobin Yvon Nanolog with Horiba Fluorohub single photon counting controller

Excitation

Continuous Xe arc lamp (450W)
Pulsed 376, 441, 488, 654, 784, 1310 nm

Detection

250-1700 nm

Time Resolution

50ps (TCSPC)

Sample Temperature Range

-25°C to +150°C (bath circulator)

Sampling Modules

Liquid / Solid / Powder / Film

Additional Tools

3D mapping, simulation and analysis for SWCNTs excitation‐emission map simulation and analysis.
FRET in SWCNT bundles, length distribution analysis, and purification applications

Applications

Photophysical properties
Fluorescence emission and decay mechanisms assessment
Energy and/or electron transfer processes, Semiconductors
Drug delivery/release, Enzyme kinetics, Gene regulation, Protein folding/denaturation
Environmental, Food authentication

Additional Information

Dr. Nikos Tagmatarchis, tagmatar@eie.gr

Ask for more information on availability,dates and pricing Submit Your Query
provided at Innovation-el by:
IESL/FORTH Heraklion
TPCI/NHRF Αthens