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Issue 27, 2018
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Defect-induced betavoltaic enhancement in black titania nanotube arrays

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Utilizing high-energy beta particles emitted from radioisotopes for long-lifetime betavoltaic cells is a great challenge due to their low energy conversion efficiency (ECE). Here we report a betavoltaic cell fabricated using black titania nanotube arrays (TiO2 NTAs) by electrochemical anodization and Ar-annealing techniques. The obtained samples show enhanced electrical conductivity as well as Vis-NIR light absorption by the introduction of oxygen vacancy (OV) and Ti3+ defects in reduced TiO2−x NTAs. A 20 mCi63 Ni source was assembled into TiO2 NTAs to form a sandwich-type betavoltaic cell. By IV measurements, the Ar-annealed TiO2 NTAs at 650 °C exhibited a maximum ECE of 3.65% with Voc = 1.13 V, Jsc = 103.3 nA cm−2, and Pmax = 37 nW cm−2. In comparison with air-annealed TiO2 NTAs, the enhancement of the betavoltaic effect in reduced TiO2−x NTAs can be attributed to the suppression of e–h recombination induced by the generation of OV and Ti3+ defects, serving as electron donors as well as electron traps that not only contribute to the increase of electrical conductance, but also facilitate the charge carrier separation.

Graphical abstract: Defect-induced betavoltaic enhancement in black titania nanotube arrays

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Publication details

The article was received on 08 Apr 2018, accepted on 06 Jun 2018 and first published on 07 Jun 2018

Article type: Paper
DOI: 10.1039/C8NR02824A
Citation: Nanoscale, 2018,10, 13028-13036
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    Defect-induced betavoltaic enhancement in black titania nanotube arrays

    N. Wang, Y. Ma, J. Chen, C. Chen, H. San, J. Chen and Z. Cheng, Nanoscale, 2018, 10, 13028
    DOI: 10.1039/C8NR02824A

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