Strong Photocurrent from Two-Dimensional Excitons in Solution-Processed Stacked Perovskite Semiconductor Sheets

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• 作者：Shahab Ahmad ; Pawan K. Kanaujia ; Harry J. Beeson ; Antonio Abate ; Felix Deschler ; Dan Credgington ; Ullrich Steiner ; G. Vijaya Prakash ; Jeremy J. Baumberg
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 18, 2015
• 年：2015
• 卷：7
• 期：45
• 页码：25227-25236
• 全文大小：683K
• ISSN：1944-8252

文摘

Room-temperature photocurrent measurements in two-dimensional (2D) inorganic鈥搊rganic perovskite devices reveal that excitons strongly contribute to the photocurrents despite possessing binding energies over 10 times larger than the thermal energies. The p-type (C₆H₉C₂H₄NH₃)₂PbI₄ liberates photocarriers at metallic Schottky aluminum contacts, but incorporating electron- and hole-transport layers enhances the extracted photocurrents by 100-fold. A further 10-fold gain is found when TiO₂ nanoparticles are directly integrated into the perovskite layers, although the 2D exciton semiconducting layers are not significantly disrupted. These results show that strong excitonic materials may be useful as photovoltaic materials despite high exciton binding energies and suggest mechanisms to better understand the photovoltaic properties of the related three-dimensional perovskites.