Tantalum oxide electron-selective heterocontacts for silicon photovoltaics and photoelectrochemical water reduction

Yimao Wan, Siva Krishna Karuturi, Christian Samundsett, James Bullock, Mark Hettick, Di Yan, Jun Peng, Parvathala Reddy Narangari, Sudha Mokkapati, Hark Hoe Tan, Chennupati Jagadish, Ali Javey, Andres Cuevas

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Crystalline silicon (c-Si) solar cells have been dominating the photovoltaic (PV) market for decades, and c-Si based photoelectrochemical (PEC) cells are regarded as one of the most promising routes for water splitting and renewable production of hydrogen. In this work, we demonstrate a nanoscale tantalum oxide (TaOx, ∼6 nm) as an electron-selective heterocontact, simultaneously providing high-quality passivation to the silicon surface and effective transport of electrons to either an external circuit or a water-splitting catalyst. The PV application of TaOx is demonstrated by a proof-of-concept device having a conversion efficiency of 19.1%. In addition, the PEC application is demonstrated by a photon-to-current efficiency (with additional applied bias) of 7.7%. These results represent a 2% and 3.8% absolute enhancement over control devices without a TaOx interlayer, respectively. The methods presented in this Letter are not limited to c-Si based devices and can be viewed as a more general approach to the interface engineering of optoelectronic and photoelectrochemical applications.

Original languageEnglish
Pages (from-to)125-131
Number of pages7
JournalACS Energy Letters
Issue number1
Publication statusPublished - 12 Jan 2018
Externally publishedYes

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