Electrical Junction Behavior of Poly(3,4-ethylenedioxythiophene) (PEDOT) Contacts to H-Terminated and CH3-Terminated p-, n-, and n+-Si(111) Surfaces

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• 作者：Michael G. Walter ; Xueliang Liu ; Leslie E. O鈥橪eary ; Bruce S. Brunschwig ; Nathan S. Lewis
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：July 18, 2013
• 年：2013
• 卷：117
• 期：28
• 页码：14485-14492
• 全文大小：479K
• 年卷期：v.117,no.28(July 18, 2013)
• ISSN：1932-7455

文摘

The electronic and photovoltaic properties of junctions between the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and Si(111) surfaces have been investigated for a range of doping types, doping levels, and surface functionalization of the Si. PEDOT鈥損oly(styrenesulfonate) (PSS) formed ohmic, low resistance contacts to H-terminated and CH₃-terminated p-type Si(111) surfaces. In contrast, PEDOT formed high barrier height (0.8鈥?.0 V) contacts to n-Si(111) surfaces, with CH₃-terminated n-Si(111)/PEDOT contacts showing slightly higher barrier heights (1.01 eV) than H-terminated n-Si(111)/PEDOT contacts (0.89 V). PEDOT contacts to CH₃-terminated and H-terminated n-Si(111) surfaces both produced photovoltages under illumination in accord with the Shockley diode limit based on bulk/recombination diffusion in the semiconductor. Such devices produced solar energy-conversion efficiencies of 5.7% under 100 mW cm^鈥? of simulated air mass 1.5 illumination. The electrical properties of PEDOT contacts to CH₃-terminated Si surfaces were significantly more stable in an air ambient than the electrical properties of PEDOT contacts to H-terminated Si surfaces. PEDOT films produced a low resistance, tunnel-barrier type of ohmic contact to n⁺-Si(111) surfaces. Hence, through various combinations of doping type, doping level, and surface functionalization, the PEDOT/Si contact system offers a wide range of opportunities for integration into monolithic photovoltaic and/or artificial photosynthetic systems.