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Department of Physics and Astronomy Collins Research Group

Organic Electronics Facilities

Substrate Preparation

Clean hood, fume hood, and vacuum oven facilities enable safe and particle-free environments for substrate cleaving, cleaning, wet chemistry, and surface treatments for electronic-grade device substrates.

 

Solution Deposition

A dedicated glovebox facility creates a pristine nitrogen environment for solution deposition of optoelectronic thin films. The atmosphere is actively scrubbed to <0.1ppm of O2 and ~0.1ppm of H2O as well as activated carbon solvent removal from the atmosphere. Inside a microbalance is used to precisely weigh materials for solution prep. A spincoater casts standard thin films, while a custom blade coater mimics roll-to-roll deposition and additionally is capable of in-situ UV-visible spectroscopy to monitor the film formation process.

 

Physical Vapor Deposition

The Angstrom Engineering NexDep is fully computer automated for multilayer-multisource thin film physical vapor deposition. The tool is coupled into the glovebox to eliminate exposure to the atmosphere and enables pumpdown to <1×10^-7 Torr base pressure in <20 minutes. Six sources includes four thermal sources for metals and two temperature-controlled RADAK sources for small molecule deposition.

Device Test Bed

A custom light-controlled and temperature-stabilized device probe station within a dedicated glovebox enables pristine, state-of-the-art testing and measurement of optoelectronic devices. Four 2-terminal devices are individually probed with a 2-GHz bandwidth switch and high-throughput pogo-pin contacts for no-tool chip switching. An articulated computer-controlled mirror enables beam-steering optimization on devices for light coupled from behind the glovebox. High-power LEDs enable DC light-biasing while an avalanche photodiode is used for time-resolved photoluminescence (trPL).

Light Sources and Light Management

Our repertoire of light sources include an AAA AM1.5G solar simulated spectrum, a chopped monochromated light spectrum (e.g. photocurrent spectroscopy), a nanosecond pulsed wavelength-tunable laser (for time-delayed collection field ‘TDCF’ or transient photovolatage ‘TPV’), and monochromatic picosecond 80MHz pulsed laser (trPL).

 

 

 

 

All light sources are computer-controlled and selected. They are all coupled into the glovebox onto the same device testbed, making possible a preprogramed suite of optoelectronic measurements with high reproducibility and throughput.

Electronics Measurement

Each device on a chip is measured via an automated sequence with specific measurements and test parameters coded by the researcher. The Keithley 2450 enables DC IV measurements (e.g. power curves for solar cells or luminescence effficiency for OLEDs). The LeCroy GHz 12-bit dynamic range oscilloscope is paired with the 240 MHz Tektronix function generator and custom amplifiers for measurement of nanosecond device dynamics (e.g. TDCF, TPV). A Princeton lock-in amplifier enables high sensitivity spectroscopy. A PicoQuant timer is used for trPL .

Microscopy

A Nikon Eclipse LV100 polarzied optical microscope is used for micrographs of birefringent or dichroic micro domains in organic films. A binoscope enables convenient magnified viewing of small samples. Both scopes are CCD-coupled for full image documentation.