Eermi level pinning

The photoelectron emission microscopy (PEEM) investigations of Imbihl and coworkers [91] (Eigure 22) have nicely confirmed not only the potential-controlled variation in the work function of model Pt electrodes deposited on YSZ but also the Eermi-level pinning between Pt and YSZ. 

Enhancing the catalysis at the surface of PEC electrodes results in a lower kinetic overpotential and an increase in photocurrent. The effectiveness of the catalysts after surface treatment can be determined by utilizing three-electrode j-V measurements (see Section Three-Electrode j-V and Photocurrent Onset ) as well as IPCE measurements (see Chapter Incident Photon-to-Current Efficiency and Photocurrent Spectroscopy ). It may also useful to perform Mott-Schottky (see Section Mott-Schottky ) to determine any impacts these catalysts may have on the band structure (e.g., due to Eermi level pinning). 

E. Yablonovitchet al., Band-Bending, Eermi Level Pinning and Surface fixed Charge on Chemically Prepared GaAs Surfaces, Appl. Phys. Lett. 1989,54, 555-557. 

Bard AJ, Bocarsly AB, Fan FRF, Walton EG, Wrighton MS (1980) The concept of Eermi level pinning at semiconductorAiquid junctions consequences for energy conversion efficiency and selection of useful solution redox couples in solar devices. J Am Chem Soc 102 3671-3677... 

The group did observe the vacuum-level rule (5 = 1) as long as the work function of the electrode fell between upper and lower limits. However, out of these limits, complete Eermi level pinning (5 = 0) took place. The overall behavior is illustrated in Eig. 15. 

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