Cryostats and other temperature control solutions allow you to control experimental conditions for precise sample measurements. This is essential to understanding fundamental photochemistry of novels materials, as well as exposing devices to conditions in which they will ultimately be used. Temperature has one of the most significant effects on a material’s ground and excited state dynamics, altering the radiative and non-radiative rates through increased or decreased coupling of vibrational modes.
Edinburgh Instruments, Ltd., utilizes multiple types of sample holders for temperatures as low as 4 K and up to 600 °C, the broadest range available on the market today. These fit into our FLS1000 Photoluminescence Spectrometer and FS5 Spectrofluorometer, as well as our LP980 Transient Absorption (Flash Photolysis) Spectrometer. We can integrate almost any cryostat from Janis, ARS, or Oxford for straightforward coupling into the sample chamber of our instruments for measurements of solutions or solids. This includes closed cycle He cyrostats down to 4 K that mount from underneath the sample chamber in the FLS1000. For more routine measurements of solutions, we incorporate a TE-cooled cuvette holder that operates from -10 °C to 105 °C (extended range from -40 °C to 150 °C) with magnetic stir control, as well as a liquid nitrogen dewar for 77 K measurements of solutions placed in NMR/EPR tubes in both our FLS1000 Photoluminescence Spectrometer and FS5 Spectrofluorometer. The temperatures can be software controlled with automatic mapping routines for steady state and lifetime measurements.
Figure 1: A sample chamber mounted cryostat in the FS5, and temperature dependent lifetime Emission spectra of Rhodamine-B in H20 for temperatures 5 °C – 80 °C using the TE-Cooled cuvette sample stage.
Additionally, we have designed a temperature controlled integrating sphere, the ‘cryosphere’, which can make absolute quantum yield, optical absorption, and optical reflection measurments on powders, films and crystals from 77 K – 500 K through fiber-optic coupling to our FLS1000 Photoluminescence Spectrometer and FS5 Spectrofluorometer. We recently highlighted this cryosphere in our application note ‘Temperature Dependent Quantum Yield of Chlorophyll Fluorescence in Plant Leaves, where we looked at the temperature dependent absolute quantum yield of plant leaves (Figure 2).
Figure 2: The Cryosphere sample holder, temperature dependent emission spectra, and absolute quantum yield of plant leaves from 77 – 300 K.
Most recently, we developed an optical enclosure for temperature controlled stages from Linkam Scientific that are coupled to our FS5 and FLS1000 Spectrometers through optical fiber bundles (right). This accessory is software controlled in the same way as our cryostats accessories, and can be used for microscopy studies as well. They allow for temperature control from -196 °C up to 600 °C (model dependent) for films and powder samples only. Using this new temperature controlled stage, we studied the Luminescence Thermometry with Upconversion Materials from -100 °C to 80 °C to highlight the unique photophysical properties of these materials. Since the upcoversion process relies on electron-phonon coupling between lanthanide dopants inside a host crystalline lattice, the temperature greatly effects the vibrational (phonon) properties of the lattice and subsequent emissive properties of these materials, as highlighted in Figure 3 below.
Edinburgh Instruments is proud to be the world leader in measuring and quantifying temperature dependent photoluminescence and transient absorption measurements. We would encourage you to contact our team to ask any questions you may have to propel your research to the highest level.
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