| Summary: | <p><p>The power conversion efficiency of solar cells is strongly impacted by an unwanted loss of charge carriers occurring at semiconductor surfaces and interfaces. Here the use of ion-charged oxide nanolayers to enhance the passivation of silicon surfaces via the field effect mechanism is reported. The first report of enhanced passivation from rubidium and cesium ion-charged oxide nanolayers is provided. The charge state and formation energy of ion-charged silicon dioxide are calculated from first principles. Ion embedding is demonstrated and exploited to control the interface population of carriers and minimize electron-hole pair recombination. The passivation quality directly improves with charge concentration, yet excess ions can produce detrimental interface states. An optimal ionic charge concentration of ≈1.5 × 10<sup>12</sup> q cm<sup>−2</sup> is deduced, and a recombination velocity and current density as low as 2.8 cm s<sup>−1</sup> and 7.8 fA cm<sup>−2</sup> are achieved at the Si-SiO<sub>2</sub> interface. Maximized charge is shown to provide efficiency improvements as high as 0.7% absolute. This work provides a unique route to enhance passivation without compromising the film synthesis, thus retaining the antireflection and hydrogenation film properties. As such, ion-charged dielectrics provide complementary paths for surface and interface optimization in future single-junction and tandem solar cells.</p>
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