This Request for Proposal (“RFP”) is an invitation by the University to prospective Proponents to submit Proposals for the provision of a Spectrofluorometer, including installation.
This equipment will be essential in a wide range of light-based spectroscopy on optically active species varying from nanoparticles to molecules in form of dispersions, powders and thin films. Our main focus is set on the study of lanthanide-based molecules and materials (upconversion and downshifting), yet other species and compounds may be tested as well. The wavelength of the used excitation light covers the range of UV to near-infrared (NIR), whereas lamps and laser diodes can be used. The wavelength range of the emitted light that will be detected spans the UV (185 nm) to NIR (1700 nm) spectral range. The data is taken and plotted automatically, and also being easy to export and analyze in common software (Origin, Excel), after the user places the sample in the proper location and sets the mode of the data acquisition. Besides emission intensity measurements, quantum yield and time-resolved measurements for lifetime determination will be performed over a wide temperature range (< 10 K to 70 °C).
General Description:
The spectrofluorometer is a high sensitivity tool to be used in the characterization (optical spectroscopy) of lanthanide-based materials at the nano- and microscale as well as molecular materials (single crystals, powders, dispersions, solution, and films). Key features of the instrument will be its suitability for quantum yield assessment and time-resolved spectroscopy to determine photoluminescence lifetimes. The optically active samples that will be investigated require excitation with UV-vis and NIR light, respectively. The instrument will allow the detection of the subsequent photoluminescence in the UV to NIR spectral region. The obtained data will be used, among other purposes, to determine emission profile, quantum yield, lifetime, and electron relaxation mechanisms in lanthanide-based upconverting and downshifting materials and molecules as well as their hybrids. The tool is expected to be equipped with laser diodes and detectors that are sensitive enough for the excitation and detection of upconversion emission, even from ultra-small, weakly emitting probes (solid state and in diluted dispersions). Along with its good sensitivity, the instrument will allow for the collection of data with reliable accuracy, in a rapid and repeatable fashion.
The tool must be fully automated and easy to use. It should have attractive features such as spectral correction or a self-calibration mode. The tool must also be based on a modular design that renders it flexible to any future upgrades that may be needed to expand the research into other areas of interest. For best performance, the tool must provide maximum stray light rejection and scanning resolution combined with great spectral resolution and on-the-spot data acquisition, which is ideal for expediting experiments and their reproducibility. The tool must also be equipped with state-of-the-art computer software for data acquisition and treatment.
Necessary for the research is the understanding of excited states dynamics, to which the lifetime of the probes (in dispersion, solution, and solid state) is of interest. To carry out such studies and related experiments, the tool must be equipped with advanced time-domain lifetime measurement capability, along with steady-state fluorescence spectroscopy. Lifetimes in the range from micro- to milliseconds must be accessible.
In order to suit our intended target experiments, the light sources in the tool can be a combination of a Xenon lamp (from which the excitation wavelength suitable for UV-vis excitation of organic phosphors and ligand scaffolds in lanthanide-based complexes will be chosen) and laser diodes (980 nm for e.g. Yb3+ and 800 nm for e.g. Nd3+). All integrated excitation sources will allow for tunable, pulsed maximum excitation to suit the characteristic lifetimes of lanthanide-based luminescent samples (micro- to milliseconds). The pulse repetition rate and width will be tunable by software to ensure a complete decay of the excited states of the probes prior to the next excitation step.
In addition to a detector for the UV-vis light range, a NIR detector capable to detect NIR emission up to not less than 1700 nm is needed in order to carry out steady-state and lifetime measurements in the UV to NIR range. Overall, with the above description, the system would be able to carry out both UV-vis and NIR steady-state, lifetime, and quantum yield experiments using the same tool. The system must allow for temperature control of the samples between less than 10 K and up to at least 70 °C, in order to study temperature-dependent optical properties. The instrument will be equipped with a number of optical filters, including a set of UV-VIS and NIR filters. Cut-off, long- and short-pass filters will be essential for UV and NIR spectroscopy to block undesired photoluminescence such as second harmonic signals originating from the upconversion emission or the excitation source. The relevant module in the overall tool set must have an integrating sphere capable of accommodating samples in form of liquid, solid (including powder) and thin film. A computer with drop-down student-friendly menus allowing easy operation and control of the overall system is one of the keys to this acquisition.
Mandatory Minimum Specifications:
1.Spectrofluorometer
1.1 Equipment modules must allow photoluminescence spectroscopy, quantum yield assessment, and photoluminescence lifetime measurements in an emission wavelength region from 185 nm to at least 1700 nm (NIR), using UV or NIR excitation, respectively.
1.2 Equipment must have a high enough sensitivity to detect weak upconversion and NIR emission from lanthanide-based nanoparticles (and similar weakly emitting optical probes), operating in steady-state, time-resolved and quantum yield assessment mode.
1.3 Equipment must have the corresponding excitation and emission monochromators.
1.4 Equipment must have the necessary (computer-controlled) diffraction gratings for emission detection in the UV-vis and NIR spectral region of the included detectors, and excitation in the UV-vis spectral region.
1.5 Equipment must have accuracy of fraction of 1 nm.
1.6 Equipment must have liquid, thin film, and powder test capability.
1.7 Equipment must be modular with potential for adding future modular upgrades.
1.8 Equipment must be automated, driven by its own central computer that must be equipped with all necessary programs to interface with the various modes of the tool.
1.9 Equipment must have light source excitation power of no less than 75 W for UV-vis in continuous operation mode.
1.10 Equipment must have a 980 nm laser diode of no less than 1 W (beam quality and power density on the sample must allow for excitation of upconversion emission).
1.11 Equipment must have an 800 nm laser diode of no less than 1 W (beam quality and power density on the sample must allow for excitation of upconversion emission).
1.12 Equipment must have excitation sources (UV-vis) and diodes (800 nm, 980 nm) that can be run in continous and pulsed mode with computer-controlled repetition rate and pulse width suitable for long lifetimes of lanthanides (micro- to millisecond range).
1.13 Equipment must have excitation sources (UV-vis and NIR) with power control.
1.14 Equipment must have short-pass and long-pass filters for upconversion and downshifting spectroscopy incorporated into it.
1.15 Equipment must have a set of cut-off filters incorporated into it.
1.16 Equipment must include a single-photon counter or equivalent alternative for time-resolved spectroscopy (lifetime module).
1.17 Equipment must have a quantum yield module, with integrating sphere and all necessary accessories to measure the quantum yield of powders, films and liquids, operating in the full spectral range of the UV-vis and NIR detectors.
1.18 Equipment must have temperature controllers, including all necessary accessories, to set the sample temperature between lower than10 K to no less than 70 °C.
1.19 Where needed (for instance in case of closed cycle helium cryostat system), equipment must have its own closed loop cooling water circulator.
1.20 Equipment must have all the necessary sample compartments, transmission parts, temperature controlled sample holder, and solid/liquid/powder sample holders.
1.21 Equipment must have a sample compartment large enough to accommodate sample holders for liquids (cuvettes), thin films, and powders, including temperature-controlled sample holders.
1.22 Where needed (e.g. in case of liquid nitrogen cooled detectors), equipment must have a nitrogen dewar assembly.
2.Other Requirements
2.1 Installation and training must be included.
2.2 Must include one (1) year warranty on parts and labor.
2.3 Equipment must fit on space of 122 cm x 90 cm in size available on an optical table. Stacking of modules, where appropriate, is allowed. Placement of pumps and cooling systems on the floor, where required and appropriate, is allowed.
2.4 Equipment must pass through the lab’s door, which is 88 cm wide.
Point Rated Criteria
1.Performance and Robustness
1.1 Describe the supplier’s track record for producing high-quality, high-resolution research equipment.
1.2 Describe the general ability and unique features of the system and its individual modules and/or components, and how they are suited to the research intended.
1.3 Please elaborate on maximum stray light rejection.
1.4 Please elaborate on the resolution of the monochromator, including the achievable minimum step size.
1.5 Describe the expected lifetime of system given regular use and user maintenance.
2.Operations and Maintenance
2.1 Describe how frequently the equipment will need maintenance if used properly by researcher.
2.2 Describe your ability to provide additional extended warranty at no extra cost.
2.3 Describe what is included in the warranty (i.e. preventative maintenance, cost of parts, repairs, replacements, travels, shipping, technical support, software upgrades, etc).
2.4 Demonstrate how you achieve a low operation costs, including consumables, and power consumption.
2.5 Describe how the equipment is spectrally calibrated / can be callibrated once installed in the lab (the system in general and the interagting sphere).
2.6 Describe which gratings are included in the monochromators of the equipment (excitation and emission).
3.Detection Mode
3.1 Please describe the best spectral resolution (in nm) that can be obtained in VIS and NIR.
3.2 Describe the sensitivity of the UV-vis detector (in RMS).
3.3 Describe the spectral range that can be detected by the included emission detectors.
3.4 Describe the sensitivity of the NIR detector (please provide responsivity of the detector in A/W as a function of the wavelength).
3.5 Describe the wavelength range and spectral resolution of the quantum yield accessory/module.
3.6 Describe the lifetime range accessible in UV-vis and NIR spectral region when the time-resolved module is used.
4.General
4.1 Describe the maximum power density that can be achieved at the sample using the 980 nm and 800 nm excitation sources, respectively.
4.2 Describe the temperature control of the instrument.
4.3 Describe how low temperatures (down to less than 10 K) will be achieved. The preference is for a closed cycle helium cryostat system.
4.4 Describe the flexibility of the system to add additional detectors, excitation sources, sample holders, connection to other optical instruments, or other accessories.
4.5 Describe the software and its functions with respect to data acquisition, plotting, analysis and export the computer will be equipped with.
4.6 Describe the user friendliness of the system in terms of switching between excitation sources and emission detectors, switching between modes (steady-state, lifetime, quantum yield), as well as of the included instrument control and data analysis software.
4.7 Describe the capability of the equipment to perform spectral correction of the detected emission.
5.Support
5.1 Describe the response time, available hours, and quality of technical support.
