Enhanced solar energy conversion in Au-doped, single-wall carbon nanotube-Si heterojunction cells
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NANO EXPRESS
Open Access
Enhanced solar energy conversion in Au-doped, single-wall carbon nanotube-Si heterojunction cells Leifeng Chen1,2*, Hong He2,3, Shijun Zhang1, Chen Xu1, Jianjiang Zhao1, Shichao Zhao2, Yuhong Mi2 and Deren Yang1
Abstract The power conversion efficiency (PCE) of single-wall carbon nanotube (SCNT)/n-type crystalline silicon heterojunction photovoltaic devices is significantly improved by Au doping. It is found that the overall PCE was significantly increased to threefold. The efficiency enhancement of photovoltaic devices is mainly the improved electrical conductivity of SCNT by increasing the carrier concentration and the enhancing the absorbance of active layers by Au nanoparticles. The Au doping can lead to an increase of the open circuit voltage through adjusting the Fermi level of SCNT and then enhancing the built-in potential in the SCNT/n-Si junction. This fabrication is easy, cost-effective, and easily scaled up, which demonstrates that such Au-doped SCNT/Si cells possess promising potential in energy harvesting application. Keywords: Solar cell, Single-wall carbon nanotube, Chemical doping, Conductivity, Au nanoparticles, Plasmon resonance
Background Photovoltaic devices based on nanomaterials may be one kind of next-generation solar cells due to their potential tendency of high efficiency and low cost [1]. Among them, carbon nanotube (CNT), possessing one-dimensional nanoscale structure, high aspect ratios, large surface area [2], high mobility [3], and excellent optical and electronic properties, could be beneficial to exciton dissociation and charge carrier transport, which allow them to be useful in photovoltaic devices [4-8]. In recent years photovoltaic devices and photovoltaic conversion based on the heterojunctions of CNT and n-type silicon have been investigated [9-12]. In those devices, electron–hole pairs are generated in CNT under illumination and are separated at the heterojunctions. This means that the CNT acts as the active layer of the cells for exciton generation, charge collection, and transportation, while the heterojunction acts for charge * Correspondence: [email protected] 1 State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China 2 College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China Full list of author information is available at the end of the article
dissociation. The conductivity and transparency of the single-wall carbon nanotube (SCNT) films are two important factors for fabricating the higher performance of SCNT/n-Si solar cell. Kozawa had found that the power conversion efficiency (PCE) strongly depended on the thickness of the SCNT network and showed a maximum value at the optimized thickness [13]. Li had found that photovoltaic conversion of SCNT/n-silicon heterojunctions could be greatly enhanced by improving the conductivity of SCNT [14]. Therefore, the efficiency of the solar cells
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