Physical Chemistry

The Schlenker Group uses a variety of spectroscopic techniques to probe interfacial charge dynamics of energy-related materials within their native operating environment. Measurements range on timescales of picoseconds to microseconds, using various specialized instrumentation. Many of our experiments involve spectroscopy on device relevant materials.

Photoinduced Absorption

Transient Absorption

Charge Modulation Spectroscopy

Electroluminescence Spectroscopy

Potentiodynamic Sum Frequency Generation

Lock-in Detected Spectroscopic Measurements

Lock-in detected photoinduced absorption or photoluminescence measurements allow for sensitive detection of excited state spectroscopic signatures. The lock-in amplifier measures only signals that are at the same frequency as the modulated probe beam. This experiment is not time resolved, and measures changes in a quasi-steady state.

Pump-probe Transient Absorption

The transient absorption set-up allows for time-resolved measurements of excited state signatures. A laser pulse is used to excite a sample, known as the 'pump' pulse. A second laser pulse (the 'probe') is transmitted through the sample to measure the excited state properties of the material. The probe pulse is sent through a delay line, which allows control of the time after excitation that a measurement is made. Transient absorption is very important in our work for identifying the active species that drive energy conversion processes.