One-Step Deposition of Photovoltaic Layers Using Iodide Terminated PbS Quantum Dots
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- 作者：Sungwoo Kim ; Jaehong Noh ; Hyekyoung Choi ; Heonseok Ha ; Jung Hoon Song ; Hyung Cheoul Shim ; Jihoon Jang ; Matthew C. Beard ; Sohee Jeong
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2014
- 出版时间：November 20, 2014
- 年：2014
- 卷：5
- 期：22
- 页码：4002-4007
- 全文大小：468K
- ISSN：1948-7185
文摘
We present a one-step layer deposition procedure employing ammonium iodide (NH4I) to achieve photovoltaic quality PbS quantum dot (QD) layers. Ammonium iodide is used to replace the long alkyl organic native ligands binding to the QD surface resulting in iodide terminated QDs that are stabilized in polar solvents such as N,N-dimethylformamide without particle aggregation. We extensively characterized the iodide terminated PbS QD via UV鈥搗is absorption, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), FT-IR transmission spectroscopy, and X-ray photoelectron spectroscopy (XPS). Finally, we fabricated PbS QD photovoltaic cells that employ the iodide terminated PbS QDs. The resulting QD-PV devices achieved a best power conversion efficiency of 2.36% under ambient conditions that is limited by the layer thickness. The PV characteristics compare favorably to similar devices that were prepared using the standard layer-by-layer ethandithiol (EDT) treatment that had a similar layer thickness.