Question regarding Beta-voltaic cells and their efficiency

[andrew_bak]

Why are beta voltaic cells so inefficient? Is it because the incident electrons are incredibly fast? According to a research, the incident electrons that get absorbed by the voltaic material are so fast that most of their energy is wasted as phonon and sonic energy. If we substantially slow down the electrons; will the conversion efficiency rise? If yes, how slow should they be? And by how much will the efficiency rise?

 

[berkeman]

According to a research

Can you post a link? Thanks.

 

[andrew_bak]

Can you post a link? Thanks.

I googled through dozens of posts to find that claim. I don't recall exactly which one. It would be difficult for me to find the corresponding link.

 

[berkeman]

I did a Google search of the first sentence of your first post above, and after accepting Google's suggestion of making betavoltaic one word, this was the first hit on the list:

https://phys.org/news/2020-09-betavoltaic-technology-dyes-energy-production.html

One of the alternatives that could potentially be the answer to these problems is the "betavoltaic cell." These cells are a type of power source akin to photovoltaic cells that, instead of producing an electric current by capturing visible or ultraviolet light, creates electricity using a type of radiation (beta decay) generated internally by a radioactive material. The biggest issue with existing betavoltaic cells is their low conversion efficiency. This means that only a very tiny portion of the emitted radiation can be converted into electric energy.

In a recent study published in Chemical Communications and selected as the cover image of its July issue, scientists from Daegu Gyeongbuk Institute of Science and Technology (DGIST) in Korea, led by Prof Su-Il In, explore a new technique to boost the performance of betavoltaic cells. To achieve this, they took a page from a technique previously used in photovoltaic cells: sensitizing dyes. In the proposed betavoltaic cell, the electrons in ruthenium-based dye used are "sensitive" to the beta radiation emitted by the radioactive source material. This means that electrons in the dye are more easily excited into higher energy states, making it easier for them to then jump from the dye to the material on the other pole of the battery, thus completing a circuit.

 

[andrew_bak]

I did a Google search of the first sentence of your first post above, and after accepting Google's suggestion of making betavoltaic one word, this was the first hit on the list:

https://phys.org/news/2020-09-betavoltaic-technology-dyes-energy-production.html

I see. So basically, by using a "sensitive" material would improve efficiency and altering the speed of the incident electrons has no effect? Thank you.