摘要
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 63Ni with an apparent emission activity density of 7.26×10~7 and 1.81×10~8 Bq cm^(-2), betavoltaic performance levels were calculated at a vacuum degree range of 1×10~5 to 1×10^(-1) Pa and measured at 1.0×10~5 and 1.0×10~4 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 Isc, Voc,and Pmax of the betavoltaic with low apparent activity density 63Ni are more significant than those of the betavoltaic with high apparent activity density ^(63)Ni. Moreover, the improved efficiencies of the measured performances are larger than the calculated efficiencies because of the low ratio of Isc and reverse saturation current (I_0). The values of I0, 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.
基金
supported by the National Natural Science Foundation of China (Grant Nos. 11505096 & 11675076)
the National Defense Basic Scientific Research Project (Grant No. JCKY2016605C006)
the Natural Science Foundation of Jiangsu Province (Grant No. BK20150735)
the Shanghai Aerospace Science and Technology Innovation Fund
the Jiangsu Planned Projects for Postdoctoral Research Funds (Grant No. 1601139B)
the Foundation of Graduate Innovation Center in NUAA (Grant No.kfjj20160609)
the Priority Academic Program Development of Jiangsu Higher Education Institutions
the Fundamental Research Funds for the Central Universities (Grant No. NJ20160031)
