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Affiliation of Author(s):材料科学与技术学院

Title of Paper:Vacuum degree effects on betavoltaics irradiated by Ni-63 with differently apparent activity densities

Journal:SCIENCE CHINA-TECHNOLOGICAL SCIENCES

Key Words:vacuum degree betavoltaic apparent activity density energy conversion unit MCNP5

Abstract:For many current betavoltaics, beta sources and PN junction energy conversion units are separated. The air gap between the two parts could stop part of decay beta particles, which results in inefficient performance of the betavoltaic. By employing Ni-63 with an apparent emission activity density of 7.26x10(7) and 1.81x10(8) Bq cm(-2), betavoltaic performance levels were calculated at a vacuum degree range of 1x10(5) to 1x10(-1) Pa and measured at 1.0x10(5) and 1.0x10(4) Pa, respectively. Results show that betavoltaic performance levels improve significantly as the vacuum degree increases. The maximum output power (P (max)) exhibits the largest change, followed by short-circuit current (I (sc)), open-circuit voltage (V (oc)), and fill factor. The vacuum degree effects on I (sc), V (oc), and P (max) of the betavoltaic with low apparent activity density Ni-63 are more significant than those of the betavoltaic with high apparent activity density Ni-63. Moreover, the improved efficiencies of the measured performances are larger than the calculated efficiencies because of the low ratio of I (sc) and reverse saturation current (I (0)). The values of I (0), ideality factor, and shunt resistance were estimated to modify the equivalent circuit model. The calculation results based on this model are closer to the measurement results. The results of this research can provide a theoretical foundation and experimental reference for the study of vacuum degree effects on betavoltaics of the same kind.

ISSN No.:1674-7321

Translation or Not:no

Date of Publication:2017-02-01

Co-author:Zhiheng Xu,,Xiaobin Tang

Correspondence Author:Liu Yunpeng