Evaluation of a betavoltaic energy converter supporting scalable modular structure

Distinct from conventional energy‐harvesting (EH) technologies, such as the use of photovoltaic, piezoelectric, and thermoelectric effects, betavoltaic energy conversion can consistently generate uniform electric power, independent of environmental variations, and provide a constant output of high DC voltage, even under conditions of ultra‐low‐power EH. It can also dramatically reduce the energy loss incurred in the processes of voltage boosting and regulation. This study realized betavoltaic cells comprised of p‐i‐n junctions based on silicon carbide, fabricated through a customized semiconductor recipe, and a Ni foil plated with a Ni‐63 radioisotope. The betavoltaic energy converter (BEC) includes an array of 16 parallel‐connected betavoltaic cells. Experimental results demonstrate that the series and parallel connections of two BECs result in an open‐circuit voltage Voc of 3.06 V with a short‐circuit current Isc of 48.5 nA, and a Voc of 1.50 V with an Isc of 92.6 nA, respectively. The capacitor charging efficiency in terms of the current generated from the two series‐connected BECs was measured to be approximately 90.7%

Successful demonstration of an efficient I-/(SeCN)(2) redox mediator for dye-sensitized solar cells

A new I-/(SeCN)(2) redox mediator has favorable properties for dye-sensitized solar cells (DSCs) such as less visible light absorption, higher ionic conductivity, and downward shift of redox potential than I-/I-3(-). It was then applied for DSCs towards increasing energy conversion efficiency, giving a new potential for improving performance

Effective Passivation of Nanostructured TiO₂ Interfaces with PEG-Based Oligomeric Coadsorbents To Improve the Performance of Dye-Sensitized Solar Cells

A novel poly­(ethylene glycol) (PEG) based oligomeric coadsorbent was employed to passivate TiO₂ photoanodes resulting in the large increase in both open-circuit voltage (<i>V</i>_oc) and short-circuit current density (<i>J</i>_sc) primarily because of the reduced electron recombination by the effective coverage of vacant sites as well as the negative band-edge shift of TiO₂. The effective suppression of electron recombination was evidenced by electrochemical impedance spectroscopy (EIS) and by stepped light-induced transient measurements of photocurrent and voltage (SLIM-PCV). The work function measurements also showed that the existence of coadsorbents on TiO₂ interfaces is capable of shifting the band-edge of TiO₂ photoanodes upwardly resulting in the increase in photovoltage. In addition, the coadsorbent was proven to be effective even in the presence of common additives such as LiI, 4-<i>tert</i>-butylpyridine, and guanidinium thiocyanate. The effect of Li⁺ cation trapping by ethylene oxide units of the coadsorbent was particularly notable to significantly increase <i>V</i>_oc at a small expense of <i>J</i>_sc. Consequently, the introduction of novel PEG-based oligomeric coadsorbents for TiO₂ photoanodes is quite effective in the improvement of photovoltaic performance because of the simultaneous increase in both <i>V</i>_oc and <i>J</i>_sc

Chemical Effects of Tin Oxide Nanoparticles in Polymer Electrolytes-Based Dye-Sensitized Solar Cells

The effects on the photovoltaic performance of the incorporation of SnO₂ nanoparticles into the polymer of a solid-state dye-sensitized solar cell (DSC) based on the poly­(ethylene oxide)/poly­(ethylene glycol) dimethyl ether solid electrolyte are studied in this paper. It has been found that the addition of SnO₂ nanoparticles to the solid electrolyte produces several key changes in the properties of the solid-state DSC that produced a better performance of the device. Therefore, we have measured an improvement in electrolyte conductivity by a factor of 2, a linear rise in the TiO₂ conduction band position, a reduction in the electron recombination rate, and a decrease in charge-transfer resistance at the counterlectrode/electrolyte interface. All these improvements produced an increase in the power conversion efficiency from 4.5 to 5.3% at 1 sun condition, a consequence of the increase of both <i>V</i>_oc (oc = open circuit) and <i>J</i>_sc (sc = short circuit) without any sacrifice in FF (fill factor)<i>.</i> The origin of these changes has been associated to the strong Lewis acidic character of SnO₂ nanoparticles yielding to the formation of a I₃^– percolation layer for holes at the surface of SnO₂ and the reduction of the concentration of free I₃^– and K⁺ ions inside the pores of TiO₂. From these results, it is concluded that the physicochemical effects of inorganic nanofiller in the polymer electrolyte may also be considered a good route in designing the high efficiency solid-state DSCs employing the polymer electrolyte

Chemical Effects of Tin Oxide Nanoparticles in Polymer Electrolytes-Based Dye-Sensitized Solar Cells

The effects on the photovoltaic performance of the incorporation of SnO2 nanoparticles into the polymer of a solid-state dye-sensitized solar cell (DSC) based on the poly(ethylene oxide)/poly(ethylene glycol) dimethyl ether solid electrolyte are studied in this paper. It has been found that the addition of SnO2 nanoparticles to the solid electrolyte produces several key changes in the properties of the solid-state DSC that produced a better performance of the device. Therefore, we have measured an improvement in electrolyte conductivity by a factor of 2, a linear rise in the TiO2 conduction band position, a reduction in the electron recombination rate, and a decrease in charge-transfer resistance at the counterlectrode/electrolyte interface. All these improvements produced an increase in the power conversion efficiency from 4.5 to 5.3% at 1 sun condition, a consequence of the increase of both Voc (oc = open circuit) and Jsc (sc = short circuit) without any sacrifice in FF (fill factor). The origin of these changes has been associated to the strong Lewis acidic character of SnO2 nanoparticles yielding to the formation of a I3– percolation layer for holes at the surface of SnO2 and the reduction of the concentration of free I3– and K+ ions inside the pores of TiO2. From these results, it is concluded that the physicochemical effects of inorganic nanofiller in the polymer electrolyte may also be considered a good route in designing the high efficiency solid-state DSCs employing the polymer electrolyte