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We report the fabrication of sandwich-type metal/TiO 2 nanotube (TNT) array/metal structures as well as their betavoltaic effects under build-in voltage through contact potential difference. The sandwiched structure is integrated by immobilized TNT arrays on Ti foil with radioisotope 63 Ni planar source on Ni substrate (Ni– 63 Ni/TNT array/Ti). Under irradiation of the 63 Ni source with activity of 8 mCi, the structure (TNT diameter ∼ 130 nm, length ∼ 11 μm) presents optimum energy conversion efficiency of 7.30% with open-circuit voltage of 1.54 V and short-circuit current of 12.43 nA. The TNT arrays exhibit a highly potential for developing betavoltaic batteries due to its wide band gap and nanotube array configuration. The TNT-betavoltaic concept offers a facile solution for micro/nano electronics with high efficiency and long life-time instead of conventional planar junction-type batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Interaction of β particles with ECSs was simulated using Monte Carlo method. • Quasi-solid electrolyte (QSE) is used to improve the long-term stability of the device. • A IL/gel-based QSE was used to improve the performances of EBV/EPV cells. • ZnO/CdS heterojunction enhances the electrochemical redox reactions. Electrochemical betavoltaic (EBV) cells are promising power sources for low-power electronics in remote and harsh environments. However, their practical applications are limited by the organic liquid electrolytes with the inferior temperature stability and narrow electrochemical window. In this work, a quasi-solid-state EBV cell was fabricated using a high-conductive gel-based quasi-solid-electrolyte (QSE), a CdS-modificated ZnO nanorod arrays (ZNRAs) structure as the anode material, a radioactive 63Ni sheet as the cathode as well as the irradiation source. Monte Carlo (MC) simulations are utilized to determine the optimized length (2.97 μm) of the ZNRAs filled by electrolyte, Electrochemical photovoltaic (EPV) cells were used to assess and optimize the content of CdS loaded on the ZNRAs. The optimum EBV cell demonstrated an excellent long-term stability and a high energy-conversion efficiency of 10.09 % with a short-circuit current density of 0.755 μA cm−2 and an open-circuit voltage of 0.288 V. The porous CdS@ZNRAs core–shell structure filled by soft ionic liquids (IL)/gel-based QSE enables a large specific area of electrochemical interface network. The synergistic effects of 3-D CdS/ZnO heterostructure with type-II band alignment and IL/gel-based QSE are responsible for the enhanced ECE and improved long-term stability of EBV/EPV cells. [ABSTRACT FROM AUTHOR]

Highly efficient direct energy conversion utilizing the betavoltaic effect is a promising alternative for developing of maintenance-free and long-life self-generating power cells. This work demonstrates a betavoltaic-powered electrochemical cell (BPEC) using free-standing TiO 2 nanotube arrays (TNTAs) incorporated with single-wall carbon nanotubes (SWCNTs) as the beta anode, a polyiodide (I − / I 3 − ) solution as the electrolyte, and a radioisotope 63Ni/Ni sheet as the cathode as well as the irradiation source. Freestanding TNTAs were fabricated using electrochemical anodization. Monte Carlo simulations were used to investigate the interaction of the incident beta particles with the TNTAs structure. Experimentally, the photoelectrochemical characteristics were used to optimize the structural design of the BPECs. The optimum BPEC exhibited an energy conversion efficiency of 8.74% with an open circuit voltage of 0.26 V and a short circuit current density of 0.87 μA/cm2. The enhanced betavoltaic effect is attributed to the highly efficient separation and transport of beta-generated carriers through the enhanced beta-electrochemical redox reactions in the 3-D TiO 2 /liquid heterojunction as well as the extensive SWCNTs conductive network. [Display omitted] • Monte Carlo simulation is used to investigate the interaction of beta particles with energy conversion structures. • TNTAs incorporated with SWCNTs were used as the beta-anode of BPECs. • Photoelectrochemical performance is used to evaluate and optimize the structure design of BPECs. • Beta-excited electrochemical reaction is enhanced by the 3-D TiO 2 /liquid heterojunction and SWCNTs conductive network. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present the design and simulation of a p–n junction betavoltaic battery based on large-grain polysilicon. By the Monte Carlo simulation, the average penetration depth were obtained, according to which the optimal depletion region width was designed. The carriers transport model of large-grain polysilicon is used to determine the diffusion length of minority carrier. By optimizing the doping concentration, the maximum power conversion efficiency can be achieved to be 0.90% with a 10mCi/cm2 Ni-63 source radiation. [Copyright &y& Elsevier]