三碘化物
材料科学
色素敏化染料
辅助电极
石墨烯
碳纳米管
能量转换效率
纳米技术
石墨烯纳米带
电化学
电解质
化学工程
兴奋剂
电极
光电子学
化学
工程类
物理化学
作者
Xiangtong Meng,Chang Yu,Xuedan Song,Yang Liu,Shaobo Liang,Zhiqiang Liu,Ce Hao
标识
DOI:10.1002/aenm.201500180
摘要
Superior electrocatalytic activities and excellent electrochemical stabilities of inexpensive counter electrodes (CEs) are crucial to the large‐scale practical application of dye‐sensitized solar cells (DSSCs). Herein, an efficient strategy for fabricating nitrogen‐doped graphene nanoribbons (N‐GNRs) via chemical unzipping of carbon nanotubes coupled with nitrogen doping process is reported, where abundant edge sites are produced and fully exposed basal planes of GNRs are activated by the N atoms within GNRs backbone. Benefiting from such unique characteristics, when first applied as CEs for DSSCs with triiodide/iodide electrolyte, a power conversion efficiency of 8.57% is delivered, outperforming GNRs (8.01%) and being superb to that of Pt (7.84%), and outstanding electrochemical stabilities of N‐GNRs are also demonstrated. Density functional theory calculations reveal that the N species within GNRs matrix, especially the predominant quaternary ones, could remarkably decrease the ionization energy of GNRs, which is instrumental to transfer electrons rapidly from external circuit to triiodide, and reduce charge‐transfer resistance, thus contributing to the enhanced photovoltaic performance. The present work has an insight into the unique role of N species on GNRs to the triiodide reduction, and provides an efficient strategy for design of high‐efficiency carbon electrodes with fully exposed active sites in energy conversion/storage devices.
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