Modification of Hematite Electronic Properties with Trimethyl Aluminum to Enhance the Efficiency of Photoelectrodes

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• 作者：Massimo Tallarida ; Chittaranjan Das ; Dejan Cibrev ; Kaupo Kukli ; Aile Tamm ; Mikko Ritala ; Teresa Lana-Villarreal ; Roberto G贸mez ; Markku Leskel盲 ; Dieter Schmeisser
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2014
• 出版时间：October 16, 2014
• 年：2014
• 卷：5
• 期：20
• 页码：3582-3587
• 全文大小：300K
• ISSN：1948-7185

文摘

The electronic properties of hematite were investigated by means of synchrotron radiation photoemission (SR-PES) and X-ray absorption spectroscopy (XAS). Hematite samples were exposed to trimethyl aluminum (TMA) pulses, a widely used Al-precursor for the atomic layer deposition (ALD) of Al₂O₃. SR-PES and XAS showed that the electronic properties of hematite were modified by the interaction with TMA. In particular, the hybridization of O 2p states with Fe 3d and Fe 4s4p changed upon TMA pulses due to electron inclusion as polarons. The change of hybridization correlates with an enhancement of the photocurrent density due to water oxidation for the hematite electrodes. Such an enhancement has been associated with an improvement in charge carrier transport. Our findings open new perspectives for the understanding and utilization of electrode modifications by very thin ALD films and show that the interactions between metal precursors and substrates seem to be important factors in defining their electronic and photoelectrocatalytic properties.

Keywords:

ALD; water splitting; photoemission; XAS; resonant photoemission; polaron; hybridization; charge carrier transport