The Si-SiO2 interface has and will continue to play a major role in the development of silicon photovoltaic devices. This work presents a detailed examination of how charge at or near this interface influences device performance. New understanding is identified on the effect of charge-induced potential fluctuations at the silicon surface. Such fluctuations have been considered in Si-SiO2 recombination models previously, where a universal value of electrical potential deviation was used to represent the effect. However, the approach disregards that the variation occurs in the charge concentration rather than the potential. We modify the models to accurately reflect fluctuations in external charge, allowing a precise representation of surface recombination velocity, with self-consistent !" , # , and $ parameters. Correctly accounting for these parameters can provide insights into the passivation mechanisms which can aid the development of future devices. Using the corrected model, we find that the effect of charge fluctuation at the Si-SiO2 interface is significant for the depletion regime to the weak inversion regime. This indicates that surface passivation dielectrics must operate with charge concentrations in excess of 2x10 12 q/cm 2 to avoid these effects. TCAD device simulations show that the efficiency of future PERC cells can improve up to 1% absolute when optimally charged dielectric coatings are applied both at the front and rear surfaces.

A general solution-based approach to deintercalate zero-valent tin and copper from two-dimensional layered chalcogenides is presented using a one-step comproportionation reduction–oxidation reaction. The reaction is performed between the intercalated zero-valent metal and high oxidation state metal cations (Sn4+ and Cu2+) dissolved in acetone. This chemistry is shown to work for a variety of layered chalcogenides with differing morphologies and crystallinity. Copper and tin are deintercalated from powders of MoS2, MoSe2, NbSe2, and WS2 and crystalline nanoribbons of Bi2Se3, In2Se3, and GeS. This chemistry achieves a general route to remove zero-valent tin and copper from 2D layered chalcogenides.

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The production and performance of p‐type inversion layer (IL) Si solar cells, manufactured with an ion‐injection technique that produces a highly charged dielectric nanolayer, are investigated. It is demonstrated that the field‐induced electron layer underneath the dielectric can reach a dark sheet resistance of 0.95 kΩ sq−1 on a 1 Ω cm n‐type substrate, lower than any previously reported. In addition, it is shown that the implied open‐circuit voltage of a p‐type IL cell precursor with a highly charged dielectric is equivalent to that of a cell with a phosphorous emitter. In the cell precursor, light‐beam‐induced current measurements are performed, and the uniformity and performance of the IL is demonstrated. Finally, simulations are used to explain the physical characteristics of the interface leading to extremely low sheet resistances, and to assess the efficiency potential of IL cells. IL cells are predicted to reach an efficiency of 24.5%, and 24.8% on 5/10 Ω cm substrates, by replacing the phosphorous emitter with a simpler manufacturing process. This requires a charge density of beyond 2 × 1013 cm−2, as is demonstrated here. Moreover, IL cells perform even better at higher charge densities and when negative charge is optimized at the rear dielectric.