FluoTime 300

Virtual Show Day: Get a closer look at the FluoTime series

On June 17th, 2021, we held our first FluoTime Show Day. During this virtual event, a group of guests got an in-depth introduction by Christian Oelsner (Application Specialist for Spectroscopy) and Uwe Ortmann (Head of Sales and Application Specialist for Spectroscopy and Microscopy) to PicoQuant’s spectroscopy products and their capabilities. The session showcased how our products can help you in your daily research tasks. A major highlight was the FluoMic add-on, which provides a fast, easy, and reliable way to carry out steady-state and time-resolved luminescence spectroscopy with a micrometer sized, positionable observation volume. You can now request the recording of the FluoTime Virtual Show Day from our webinar website.

High performance fluorescence spectrometer

The FluoTime 300 is a fully automated, high performance fluorescence spectrometer for steady-state, life time and phosphorescence measurements. The FluoTime 300 contains the complete optics and electronics for recording steady state spectra and fluorescence decays by means of Time-Correlated Single Photon Counting (TCSPC) or Multichannel Scaling (MCS) from few picoseconds to several seconds. The system is designed to be used with picosecond pulsed diode lasers, LEDs or Xenon lamps (CW and pulsed). Multiple detector options enable a large range of system configurations from the UV up to the IR range. The system features an ultimate sensitivity with 29 000:1 Water Raman SNR. The FluoTime 300 can be used to study fluorescence and phosphorescence decays from few picoseconds to several seconds. With a large range of additional accessories the system is an excellent standard for research and analysis.

Versatile sample mounting units

A newly designed series of sample mounting units is now available
for the FluoTime 300.

Each sample mounting unit is designed around modular sample holders (standard: cuvette, optional: front-face), which allow a quick and easy change between different sample configurations, e.g., liquids, powders, or wafers. Temperature control of the cuvette holder is possible by attaching an external thermostat (tubing for the circulating fluid is pre-installed) or with an optional peltier-cooled single- or multi-cuvette sample holder. A cryostat can be integrated for measurements at low temperature. The range of available sample holders also includes a front face version for samples of up to 2 inch size. The holder permits to change position and angle of the sample with respect to the direction of excitation and detection from outside of the sample compartment. This special feature is extremely useful for an on-line optimization of the beam position on the sample while the measurement is running.

Flexible excitation sources

The FluoTime 300 is designed to be used with picosecond pulsed lasers, LEDs and Xenon flash lamps. Pulsed laser and LEDs are available in a very broad wavelength range from 255 nm to 1550 nm. They can be varied in output power and operated at any repetition rate from single shot to 80 MHz (depending on wavelength) as well as in pulse bursts at low repetition rate intervals. This special feature allows to match the excitation conditions ideally to the sample requirements, from fluorescence with short lifetimes to weak phosphorescence. A specialized driver unit of the PDL Series, the PDL 820, is used to control the individual excitation source. The FluoTime 300 can also be equipped with a Xenon arc lamp and/or a Xenon flash lamp which enable excitation at any wavelength from 200 nm to 900 nm. Along with a dedicated high-resolution monochromator steady-state excitation spectra become possible.

TCSPC and MCS based data acquisition

Several outstanding data acquisition units are available for time-resolved as well as steady-state fluorescence measurements. The TimeHarp 260 PICO offers an adjustable temporal resolution from 25 ps to 5.2 ms and is therefore the perfect choice for measuring steady-state and time-resolved emission with lifetimes ranging from a few ten picoseconds up to several milliseconds. The TimeHarp 260 NANO is a dedicated MCS board that has a minimum base resolution of 250 ns and no dead time between channels. The TimeHarp 260 NANO is therefore ideally suited for steady-state measurements or for lifetime measurements up to the second time scale. Any of these data acquisition units are the perfect match for systems equipped with a detector of the PMA Series or PMA Hybrid Series.

For measuring ultrafast dynamics the PicoHarp 300 offers an even better temporal resolution (4 ps) and is therefore recommended for FluoTime 300 systems equipped with a fast PMA Hybrid PMT (-06 or -07) or MCP-PMT detector. In that case even dynamics of tens of picoseconds can be resolved.

Several available detector types

The FluoTime 300 uses single photon counting detectors of various types, attached to an exit slit of the emission monochromator. The system can work with one or two detectors. The available detectors are either photomultiplier tubes (PMA Series or NIR-PMTs), Hybrid-PMT modules (PMA Hybrid Series) or Microchannel Plate Photomultiplier Tubes (MCP-PMTs). The detectors offer picosecond temporal resolutions and cover different spectral ranges between 180 nm and 1700 nm. Each detector includes an electro-mechanical shutter, optional cooling, and an overload protection that can be operated from the system software.

NEW -07 and -42 cathodes with spectral ranges between 220 and 870 nm, detection efficiency up to 25 %

System software "EasyTau 2"

The FluoTime 300 features an intuitive and easy-to-use system software. All measurement data files and all related analysis results are stored in a clearly arranged workspace, which resembles the familiar tree structure of a hard drive directory. Data dependencies are thus visible at first glance. Steady-State and time-resolved measurements can be performed alternatively from the same software interface.The software features three data acquisition possibilities. Specifically designed application wizards guide the user through the necessary optimization steps for performing typical measurement tasks such as fluorescence lifetime measurements, anisotropy measurements, collection of emission spectra or Time-Resolved Emission Spectra (TRES). For those familiar with the technique, a customized measurement mode for full instrument control is also available. More sophisticated application tasks, like, for example, alternating between time-resolved decays and steady-state spectra at different temperatures over night, can be easily performed through scripted data acquisition using the integrated scripting language of the EasyTau 2 software.

Steady-state and time resolved data can by analyzed through the same software interface. EasyTau 2 provides both basic data manipulation (such as arithmetic, derivation, integration, or smoothing) and fitting functions. The software’s global decay analysis features an easy-to-use graphical user interface that is capable of producing presentation-ready numerical and graphical output. Both tail and iterative reconvolution fitting routines with nonlinear error minimization are supported. Various exponential decay models (up to fifth order) or rate constant distribution models can be fitted to the observed decay to determine the fluorescence lifetimes or to study fluorescence anisotropy. Robust error analysis can be carried out with the bootstrap method.

Course on time-resolved fluorescence

PicoQuant annually holds the European short course on "Principles and Applications of Time-resolved Fluorescence Spectroscopy". The course is intended for individuals wishing an in-depth introduction to the principles of fluorescence spectroscopy and its applications to the Life Sciences. The course is held in cooperation with Prof. J.R. Lakowicz from the Center of Fluorescence Spectroscopy (CFS) in Baltimore and consists of lectures as well as instrumentation and software hands-on training. For details see the course website.

Detailed specifications are available for download as a PDF document.

All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.

NEW FluoMic brings the FluoTime 300’s power and versatility to remote samples

The FluoMic add-on provides a fast, easy, and reliable way to carry out steady-state and time-resolved luminescence spectroscopy with a micrometer sized, positionable observation volume. A special fiber coupler unit allows interfacing the spectrometer with most microscopes.Thanks to its pre-aligned optical fibers, both pulsed and CW light sources of the FluoTime 300 can be used to excite materials located in an external device. Emitted light is collected from a small area (down to 2 µm) and brought back to the detection arm of the FluoTime 300 via a detection fiber, adding spatial resolution to the spectrometer’s capabilities. Thus, the broad palette of wizard-guided or customized steady-state and time-resolved applications supported by EasyTau 2 can be applied to remote samples.

Check out this White Paper (PDF), which showcases the capabilities of the FluoMic add-on.

Advanced Automation for Time-resolved Spectroscopy

Thanks to a newly implemented interface for remote execution of scripts, the FluoTime 300 can be coupled to third-party accessories such as the liquid handling automation workstation Biomek NXP from Beckman-Coulter. This combination allows to extend the automation to loading and removing of samples from the spectrometer, simplifying the work flow for both high-throughput applications and obtaining spectroscopic snap shots at well defined time points. With such a reduction in your spectroscopic work load, you can concentrate on the most interesting tasks: analyzing and interpreting your results.

Watch the demonstration video.

Several specialized sample holders

Several specialized detectors

Integrating sphere

For all scattering samples, the use of an integrating sphere to measure the absolute photoluminescence quantum yield is mandatory. The FluoTime 300 features an integrating sphere for solutions as well as for solid samples. It is able to reproduce published literature data of selected quantum yield standards such as Rhodamin 6G, Coumarin 153, and Ru(bpy)3.

Sample holders to emasure at low temperatures

Determining electron-hole diffusion lengths in
perovskite solar cells

A critical parameter in understanding the photophysics of semiconductor solar cells is the diffusion length of the photo-excited electrons and holes in the material. Time-resolved photoluminescence quenching experiments are a valuable tool for determining diffusion lengths. The example shows data obtained from mixed halide and triiodide organometal perovskite layers in presence of either an electron (blue) or hole (red) quenching layer, or a PMMA coating (black). The decay curves were recorded at 780 nm, corresponding to the peak emission of both materials. The measured decay dynamics can be fitted to a diffusion model, allowing to derive diffusion lengths. Here, the diffusion length of the electrons and holes in the mixed halide perovskite was 1 μm while the triiodide material featured a much shorter length of 100 nm, correlating well with performance of these materials as solar cells.

Set-up:

• FluoTime 300

Reference: S. D. Stranks et al., Science, 342 (2013), p.341

Singlet oxygen produced by H₂TTP

The figure on the left shows the steady-state spectrum of the singlet oxygen emission produced by H₂TTPS in acetone and even in H₂O, which is especially challenging due to the spectral overlap of water and singlet oxygen emission. The graph on the right additionally shows the time-resolved singlet oxygen measurement using the burst mode feature of the FluoTime 300, i.e. first multiple laser pulses are used to deposit energy into the sample and then the excitation is stopped long enough to capture the comparably slow decay of the sample. A tail fit yields a lifetime of 3.4± 0.3 µs, which is in excellent agreement with the published literature value.

Set-up:

• FluoTime 300

TRPL of a GaAsP quantum well system

Transient TRPL spectrum of a quantum well illuminated at 595 nm and measured with a fluorescence lifetime spectrometer showing (a) the layer structure of the quantum well and (b) the time-resolved emission spectrum (TRES) of the wafer. The first peak at 650 nm stems from the Al0.4Ga0.6As-barrier, the peak around 735 nm from the GaAsP quantum well and the peak around 860 nm from the n-GaAs layer and the GaAs substrate. Each spectral channel can be described with a three-component exponential model. The average lifetime and the longest component of the fits are displayed. The measurement exemplifies the correlation of characteristic charge carrier dynamics in material specific spectral channels of the multi-component system.

Set-up:

• FluoTime 300

Excitation spectra of the 650 nm peak of the Al0.4Ga0.6As-barrier (blue), of the quantum well layer( light green) and of the n-GaAs-layer and GaAs substrate (dark green). The spectrum of the quantum well layer shows a prominent drop in intensity around 650 nm indicating the interaction with the barrier layer. The n-GaAs-layer and GaAs substrate on the other hand show an increase in intensity around 650 nm, which correlates with the absorption edge in the barrier at wavelengths longer than the barrier band gap. The rectangles illustrate the band gaps of the corresponding layers.

Set-up:

• FluoTime 300

Fluorescence upconversion using NaYF₄:Yb/Er

The left figure above shows the steady state upconversion spectrum of NaYF₄:Yb/Er solved in cylcohexane. The figure on the right side above displays time resolved measurement of the same sample of NaYF₄:Yb/Er solved in cylcohexane. The excitation of the sample was performed in a burst mode, i.e. first multiple laser pulses are used to deposit energy into the sample and then the excitation is stopped long enough to capture the comparably slow decay of the sample. The analysis of the data reveals a single fluorescence lifetimes of 113 µs.

The figure on the right side shows the upconversion luminescence of Er/Yb nanoparticles solved in cyclohexan. Excitation was done at 980 nm using LDH-D-C-980 laser from PicoQuant. Integration time was 2 s/point. In that configuration measurements of quantum yields are possible.

Set-up:

• FluoTime 300
• Excitation at 980 nm using a LDH-D-C-980 operated in CW mode and pulsed burst mode using a PDL 828
• Analysis: FluoFit

Sample courtesy of T. Nyokong, Rhodes University, South Africa
Sample courtesy of Dr. U. Resch-Genger, BAM

Dynamic anisotropy of Coumarin 6

The dynamic anisotropy of Coumarin 6 was studied using the FluoTime 300. The system automatically set the sample temperature, and at each temperature step, four measurements were automatically performed: IRF  and VV (parallel), VH (perpendicular), and VM (magic angle) polarized decay measurements. A quick analysis of VV and VH decays clearly shows temperature dependent behavior of the emission anisotropy. For detailed quantitative results, global reconvolution anisotropy analysis of the data set was performed. A model of a single, spherical, rotating particle with a single exponential fluorescence lifetime proved to describe the system very well, as expected for a small, highly polar particle in polar solvent. The result reveals the slightly temperature dependent single exponential fluorescence lifetime of Coumarin 6. The temperature dependence of the viscosity could be fitted to the experimentally obtained change of the rotation correlation times. Even a precise calculation of the steady-state anisotropy values was possible which were found to be in perfect agreement with the anisotropy values estimated by the Perrin equation.

Set-up:

• FluoTime 300
• Excitation: 440 nm
• Emission detected at 510 nm with 3 nm bandpass
• Analysis: FluoFit

The FluoTime 300 is a high performance fluorescence lifetime spectrometer with a steady-state add-on. It can be used to study various samples and perform several applications, including:

• Time-Resolved Fluorescence
• Singlet Oxygen
• Time-Resolved Photoluminescence (TRPL)
• Lanthanide Upconversion
• Fluorescence Anisotropy (Polarization)
• Steady-State Fluorescence Spectroscopy
• Fluorescence Anisotropy
• Quantum Yield Measurements
• Photochemistry
• LEDs, OLEDs, quantum dots

The following documents are available for download:

• Brochure about the FluoTime Series
• Datasheet FluoTime 300
• Datasheet FluoMic add-on
• Technical note: Time-Correlated Single Photon Counting (TCSPC)
• White Paper: Measuring steady-state and time-resolved photoluminescence from a positionable, micrometer-sized observation volume with the FluoMic add-on