Throughout the development of silicon heterojunction (SHJ) solar cells, the transparent conductive oxide has been regarded as an essential component of their front electrode, facilitating lateral charge transport of photogenerated carriers toward the front metal grid fingers. In rear junction (RJ)-SHJ solar cells, the (n)c-Si bulk is known to support the lateral electron transport at maximum power point injection level, provided that the contact resistance of the front contact stack is sufficiently low. This enables experimental RJ-SHJ solar cell architectures featuring a localized front carrier-selective passivating contact exclusively covering the area contacted by the metal grid. Herein, a top-down approach to the synthesis of this type of architecture is studied and its optical and electrical performance applied to different (n)-type contacts are investigated. Additionally, the potential of the localized contact architecture through Cu-plated RJ-SHJ solar cells is demonstrated. These solar cell demonstrators feature high short-circuit current density of 40.5 mA cm−2, without significantly compromising their open-circuit voltage or fill factor, enabling efficiencies well above 23%, a 2%abs improvement compared to their state before localization of the front contact.

The influence of doping with the 5d transition metal W has been studied in the quaternary (Mn,Fe)₂(P,Si) based giant magnetocaloric compounds, which is one of the most promising systems for magnetic refrigeration. It is found that W substitution can separately decrease the Curie temperature T_C and retain the thermal hysteresis ∆T_hys at an almost constant level (∼5 K) for Mn_0.6Fe_1.27-xW_xP_0.64Si_0.36 (x ≤ 0.02). Low-content W doping conserves the good magnetocaloric effect (MCE) without an obvious degradation. For x ≤ 0.02 the average magnetic entropy change |∆S_m| amounts to 11.4 Jkg⁻¹K⁻¹ for an applied magnetic field change of 2 T and the adiabatic temperature change ∆T_ad amounts to 3.9 K for an applied magnetic field change of 1.5 T. The occupancy of substitutional W atoms is determined by XRD experiments and DFT calculations. Our studies provide a good strategy to further optimize the MCE of this material family.