Improving Polymer/Nanocrystal Hybrid Solar Cell Performance via Tuning Ligand Orientation at CdSe Quantum Dot Surface

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• 作者：Weifei Fu ; Ling Wang ; Yanfang Zhang ; Ruisong Ma ; Lijian Zuo ; Jiangquan Mai ; Tsz-Ki Lau ; Shixuan Du ; Xinhui Lu ; Minmin Shi ; Hanying Li ; Hongzheng Chen
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：November 12, 2014
• 年：2014
• 卷：6
• 期：21
• 页码：19154-19160
• 全文大小：391K
• ISSN：1944-8252

文摘

Achieving superior solar cell performance based on the colloidal nanocrystals remains challenging due to their complex surface composition. Much attention has been devoted to the development of effective surface modification strategies to enhance electronic coupling between the nanocrystals to promote charge carrier transport. Herein, we aim to attach benzenedithiol ligands onto the surface of CdSe nanocrystals in the 鈥渇ace-on鈥?geometry to minimize the nanocrystal鈥搉anocrystal or polymer鈥搉anocrystal distance. Furthermore, the 鈥渆lectroactive鈥?蟺-orbitals of the benzenedithiol are expected to further enhance the electronic coupling, which facilitates charge carrier dissociation and transport. The electron mobility of CdSe QD films was improved 20 times by tuning the ligand orientation, and high performance poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b鈥瞉-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT):CdSe nanocrystal hybrid solar cells were also achieved, showing a highest power conversion efficiency of 4.18%. This research could open up a new pathway to improve further the performance of colloidal nanocrystal based solar cells.

Keywords:

hybrid solar cell; ligand orientation; electronic coupling; exciton dissociation; charge transport