CNST is equipped with state of the art instrumentation for time resolved and steady state optical and electrical characterization of materials, device fabrication, chemical synthesis, protein design and characterization. The equipment is dislocated over about 500 m2 of lab space.
Femtolab: fs laser micromachining lab
Femtolab is an advanced laser micromachining working station for direct writing in transparent media and surface modification in opaque media. A custom made Pharos Laser (Light Conversion, Lithuania) provides amplified 10 W (average power) 300 fs pulses @1030 nm with variable pulse repetition rate up to 1 MHz. A sample translation stage allows high precision micro-fabrication of 3D optofluidic circuits, waveguides, opto-chips and patterned surfaces for energy and photonics application.
fs Transient Absorption (TA) Spectroscopy lab
Ultrafast TA spectroscopy allows investigating fundamental photophysical phenomena in the time window between 50 fs and 1.6 ns. The system allows tuning of the excitation and probing wavelength in the range of 400 - 2000 nm at a repetition rate of 250 kHz which strongly improves the system sensitivity compared to the widely used 1 kHz laser systems.
The time-resolved photoluminescence (TRPL) system is based on a tunable femtosecond laser source and streak camera detection system in a spectral window between 300 and 900 nm. Non-linear optical beam-lines (second and third harmonic generation, supercontinuum generation) have been built to achieve an almost uninterrupted pump wavelength range of 270 – 1040 nm. The streak camera detection system is optimized to allow high resolution (<4 ps) measurements, even in the presence of high background signals.
ns-ms Transient Absorption Spectroscopy
This setup consists of a modular system for studying transient species generated by tunable light pulses from UV to near IR and in the time window between 3 ns and 1s.
Solar cells characterization
The setup for solar cell characterization includes tools for the identification of critical figures of merit of photovoltaic devices (e.g. a class AAA solar simulator - 4 inches beam size - to measure I-V characteristics of photovoltaic devices under AM 1.5 conditions), and a set up for Incident Photon to Charge Carrier Efficiency (IPCE) measurements, adapted for the testing of devices of different technologies - DC mode, AC mode with light biasing (white or colored illumination).
CW Spectroscopy Lab
The CW-Spectroscopy Lab is devoted to the optical and spectroscopic characterization of materials and devices, on a temporal timescale ranging from hundreds of microseconds up to steady-state conditions. It is equipped with:
- UV-VIS-NIR spectrophotometer (Perkin Elmer, Lambda1050) and a VIS-NIR spectrofluorimeter (Horiba Jobin Yvon, NanoLog) both equipped with an integrating sphere;
- CW-modulation spectroscopy setups for Electroabsorption, Photoinduced Absorption and Charge Modulation Spectroscopy measurements. These spectroscopic techniques can also be coupled to a confocal home-made microscope, with sub-micrometer (≈300 nm) spatial resolution;
- Potentiostat working station (METROHM Autolab PGstat 302) completes the set of available spectroscopic techniques with Impedance Spectroscopy, Cyclic Voltammetry, Chrono-Amperometry and Chrono-Potentiometry.
The lab is equipped with a high placing precision Microfab's jetlab 4xl-A (Altatech Semiconductor). The nozzle design enables picoliter droplets of conductive inks to be deposited with a positioning accuracy of 25 μm and a placement repeatability within 5 μm across a printable area of 210 mm by 260 mm. The second printer is a Dimatix DMP-2831, capable of producing droplets of functional materials down to 1 pl in volume. Using this highly precise deposition technology and a recently developed self-aligned printing technique, electrode gaps of 100 nm to 500 nm can be defined with high yield and uniformity while tightly controlling the volume of material deposited per droplet and the spread of material on the substrate. The lab is also equipped with an expanded version of the Dataphysics OCA15-EC tool to perform static and dynamic contact angle measurements and drop shape analysis.
WetLab and Softwall cleanroom
This laboratory is aimed to provide the instruments for materials processing, patterning and coating in a humidity and temperature controlled environment. The lab is equipped with thermal evaporators with multiple turrets, oxygen plasma ashers, sonicators, two nitrogen glove boxes, optical microscopes and a profilometer. A softwall cleanroom (class 1000 at rest) is embedded for lithographic patterning of samples (≈ 1 μm lateral patterning resolution).
Electrical Measurements and Characterization lab
The lab is fully equipped to perform detailed optoelectronic characterization of electronic devices: semiconductor parameter analyzers, LCR meter, network analyzer, pulse and arbitrary waveform generator, current/voltage amplifiers and oscilloscopes. A dedicated setup for the measurement of transient EQE by means of a set of calibrated LEDs has been installed. Measurements can be performed in ambient, in high vacuum, in a nitrogen glove box with the aid of a dedicated cryogenic probe station (4.5 – 475 K, in vacuum). In the lab there is also a JEOL Scanning Electron Microscope JSM 6010LV: Compact SEM with tungsten filament source, double detector for back-scattered and secondary electrons.
The biochemistry laboratory and the X-ray diffraction room are equipped for the structural characterization of both small molecules and proteins at low temperature. The laboratories contain all the equipment for gene amplification and cloning, protein expression, protein purification, as well as a protein crystallization platform. It includes a Beckmann-Coulter DU730 spectrophotometer, a Leica M165 stereomicroscope and a GE-Healthcare ÄKTA purifier UPC10 and a Bruker X8 Prospector diffractometer equipped with a Kappa 4-Axis goniometer, a high-flux air-cooled X-ray microfocus Cu-Kα source with multilayer optics and a 16 megapixel high dynamic range CCD detector of 62x62 mm active area.
Pulsed Laser Deposition lab
The lab research activity is devoted to the synthesis and characterization of nanostructured films and surfaces, clusters and nanostructures. The growth of nanostructured materials and surfaces is performed by means of Pulsed Laser Deposition (PLD), ion sputtering, evaporation, and co-deposition approaches.
The instrumentation of the lab includes: a PLD system, furnaces for annealing in controlled atmosphere, and a multi-wavelengths Raman spectrometers equipped also for PL measurements.
Nanostructured Fluorinated Materials lab (NFMLab)
The key objectives of the NFMLab are the design, synthesis, characterization, and application of micro- and nanostructured fluorinated materials. Lab equipment includes:
- Single crystal X-Ray diffractometer Bruker KAPPA APEX II with cryogenic system and Optical Heating and Crystallization Device for in-situ cryo-crystallization of low melting and liquid systems;
- Powder diffractometer Bruker D8 Advance with advanced high and low-temperature chamber for in-situ X-ray diffraction studies;
- UATR-FT-IR spectrophotometer ThermoNicolet;
- Differential Scanning Calorimeters (Mettler Toledo and Linkam 600) coupled with Polarized Light Optical Microscope;
- Polarized Light Optical Microscope Olympus BX51 coupled with heating and freezing stages;
- Gas Chromatography - Mass Spectrometry (with EI, CU and FAB), UV and IR spectrophotometers.
- Device Technology and Chemical Physics group
The Device Technology and Chemical Physics group has a Wet Lab for materials processing and thin film fabrication. It is also equipped with some spectroscopy tools for the active materials and devices characterization: q-switched Nd:YAG Laser coupled to a optical parametric oscillator and second harmonic generator, an iCCD + Spectrograph and liquid-N2 cryostat.
Theoretical and Computational Activity
Large scale computations are carried out using a cluster Dell PowerEdge directly deployed and administered: Debian + Sun GridEngine, 24 core Intel Xeon E5430 @2.66GHz, 16 core AMD Opteron 2389 @2.9GHz, 32 or 16 Gb RAM on each node (5 nodes). Scientific software inlcude: Gaussian03-09, Gamess-US, NWChem, Tinker, CPMD. Post-processing data analysis and small-scale calculations are carried out on Linux PCs.
Organic Synthesis lab
Key objective of the research is the development of new carbon polyconjugated materials for energy and photonics applications. For these purposes the lab is equipped with FTIR, Raman, UV-vis-NIR spectrometer and spectrophotometer for the spectroscopic characterization of the synthesized species, and diode-array HPLC and flash chromatography for the purification runs. The laboratory is equipped with all the facilities required to carry out synthesis in inert ambient, with an apparatus for purification/drying of solvents. In particular:
- Spectrophotometer Agilent Cary 5000 for the measurement of UV-vis-NIR absorption of solution, solid state and diffusive samples, with wide spectral range (175 – 3300 nm), wide photometric range (absorbance = 8) with good linearity, high resolution (UV-vis: < 0.05 nm, NIR: < 0.2 nm);
- MBRAUN SPS system for solvents purification/drying equipped with dispenser;
- Thermo Scientific Nicolet™ 6700 FT-IR spectrometer.
Theoretical and Computational Activity
The theoretical and computational lab at CNST is embedded in the Department of Chemistry, Materials and Chemical Engineering "G. Natta" of Politecnico di Milano. This activity aims to investigate the physical-chemical properties of materials studied by CNST. High level ab-initio and first principles calculations, going from density functional theory (DFT) to time dependent density functional theory (TD)-DFT, from configuration interactions (CIs) to high electron correlated methods, are used. The main research lines are:
- Modeling of the charge transport processes in high carrier mobility organic materials (small molecules and polymers);
- Spectroscopy investigation of advanced π-conjugated materials, from vibrational (IR, Raman, Resonant Raman) to electronic (UV-Vis, Photoluminescence and Transient phenomena) spectroscopies;
- Photoinduced processes in organic materials used for photovoltaic applications, focusing the investigation on polymer: fullerene interfaces;
- Study of the excited states in molecular crystals or aggregates to model multiexciton processes such as singlet fission and triplet-triplet annihilation.