  Beta cells generate electric power as carrier-producing beta irradiation from
incorporated radioisotopes bombard a series of p-n-junctions. However,
radiation damage to the semiconductors commonly used in solar cells limits beta
cells to extremely weak irradiations that generate concomitantly miniscule
electric powers, e.g. micro-Watts. By contrast, beta cells that generate many
orders-of-magnitude larger powers are possible with icosahedral boron-rich
semiconductors since their bombardment-induced atomic displacements
spontaneously self-heal. Furthermore, substitutions for Mg and Al atoms of
icosahedral-boron-rich semiconductors based on the MgAlB14 structure can
produce p-n junctions as electron transfers from doping-induced interstitial
extra-icosahedral atoms convert some normally p-type materials to n-type.
Moreover, electron-phonon interactions of the resulting readily displaceable
interstitial cations with charge carriers foster their forming large polarons.
Oppositely charged polarons repel one another at short range. These repulsions
suppress the recombination of n-type with p-type polarons thereby increasing
the beta-cell efficiency. All told, use of these icosahedral boron-rich
semiconductors could enable beta cells with electric powers that are many
orders of magnitude larger than those of existing beta cells. This development
opens a new avenue for generating electricity from nuclear decays.
