High Performance Nanostructured Silicon–Organic Quasi p–n Junction Solar Cells via Low-Temperature Deposited Hole and Electron Selective Layer

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• 作者：Yuqiang Liu ; Zhi-guo Zhang ; Zhouhui Xia ; Jie Zhang ; Yuan Liu ; Feng Liang ; Yongfang Li ; Tao Song ; Xuegong Yu ; Shuit-tong Lee ; Baoquan Sun
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：704-712
• 全文大小：480K
• ISSN：1936-086X

文摘

Silicon–organic solar cells based on conjugated polymers such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on n-type silicon (n-Si) attract wide interest because of their potential for cost-effectiveness and high-efficiency. However, a lower barrier height (Φ_b) and a shallow built in potential (V_bi) of Schottky junction between n-Si and PEDOT:PSS hinders the power conversion efficiency (PCE) in comparison with those of traditional p–n junction. Here, a strong inversion layer was formed on n-Si surface by inserting a layer of 1, 4, 5, 8, 9, 11-hexaazatriphenylene hexacarbonitrile (HAT-CN), resulting in a quasi p–n junction. External quantum efficiency spectra, capacitance–voltage, transient photovoltage decay and minority charge carriers life mapping measurements indicated that a quasi p–n junction was built due to the strong inversion effect, resulting in a high Φ_b and V_bi. The quasi p–n junction located on the front surface region of silicon substrates improved the short wavelength light conversion into photocurrent. In addition, a derivative perylene diimide (PDIN) layer between rear side of silicon and aluminum cathodes was used to block the holes from flowing to cathodes. As a result, the device with PDIN layer also improved photoresponse at longer wavelength. A champion PCE of 14.14% was achieved for the nanostructured silicon–organic device by combining HAT-CN and PDIN layers. The low temperature and simple device structure with quasi p–n junction promises cost-effective high performance photovoltaic techniques.