Ultrafast Hole Trapping and Relaxation Dynamics in p-Type CuS Nanodisks

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• 作者：John Ludwig ; Li An ; Brian Pattengale ; Qingyu Kong ; Xiaoyi Zhang ; Pinxian Xi ; Jier Huang
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：6
• 期：14
• 页码：2671-2675
• 全文大小：326K
• ISSN：1948-7185

文摘

CuS nanocrystals are potential materials for developing low-cost solar energy conversion devices. Understanding the underlying dynamics of photoinduced carriers in CuS nanocrystals is essential to improve their performance in these devices. In this work, we investigated the photoinduced hole dynamics in CuS nanodisks (NDs) using the combination of transient optical (OTA) and X-ray (XTA) absorption spectroscopy. OTA results show that the broad transient absorption in the visible region is attributed to the photoinduced hot and trapped holes. The hole trapping process occurs on a subpicosecond time scale, followed by carrier recombination (鈭?00 ps). The nature of the hole trapping sites, revealed by XTA, is characteristic of S or organic ligands on the surface of CuS NDs. These results not only suggest the possibility to control the hole dynamics by tuning the surface chemistry of CuS but also represent the first time observation of hole dynamics in semiconductor nanocrystals using XTA.