A highly transparent passivating contact (TPC) as front contact for crystalline silicon (c-Si) solar cells could in principle combine high conductivity, excellent surface passivation and high optical transparency. However, the simultaneous optimization of these features remains challenging. Here, we present a TPC consisting of a silicon-oxide tunnel layer followed by two layers of hydrogenated nanocrystalline silicon carbide (nc-SiC:H(n)) deposited at different temperatures and a sputtered indium tin oxide (ITO) layer (c-Si(n)/SiO2/nc-SiC:H(n)/ITO). While the wide band gap of nc-SiC:H(n) ensures high optical transparency, the double layer design enables good passivation and high conductivity translating into an improved short-circuit current density (40.87 mA cm−2), fill factor (80.9%) and efficiency of 23.99 ± 0.29% (certified). Additionally, this contact avoids the need for additional hydrogenation or high-temperature postdeposition annealing steps. We investigate the passivation mechanism and working principle of the TPC and provide a loss analysis based on numerical simulations outlining pathways towards conversion efficiencies of 26%.

Here we report a monolithic perovskite–perovskite–silicon triple-junction tandem solar cell with an efficiency of over 20%, an open-circuit voltage of 2.74 V, and a fill factor of 86%, which are the highest values for double- or triple-junction perovskite-based tandems reported to date. The concept and design presented here are an important milestone toward low-cost triple-junction tandem photovoltaics.

Perovskite/silicon tandem solar cells are promising to penetrate photovoltaic market. However, the wide‐bandgap perovskite absorbers used in top‐cell often suffer severe phase segregation under illumination, which restricts the operation lifetime of tandem solar cells. Here, a strain modulation strategy to fabricate light‐stable perovskite/silicon tandem solar cells is reported. By employing adenosine triphosphate, the residual tensile strain in the wide‐bandgap perovskite absorber is successfully converted to compressive strain, which mitigates light‐induced ion migration and phase segregation. Based on the wide‐bandgap perovskite with compressive strain, single‐junction solar cells with the n–i–p layout yield a power conversion efficiency (PCE) of 20.53% with the smallest voltage deficits of 440 mV. These cells also maintain 83.60% of initial PCE after 2500 h operation at the maximum power point. Finally, these top cells are integrated with silicon bottom cells in a monolithic tandem device, which achieves a PCE of 26.95% and improved light stability at open‐circuit.

In this work, we propose a route to achieve a certified efficiency of up to 24.51% for silicon heterojunction (SHJ) solar cell on a full-size n-type M2 monocrystalline-silicon Cz wafer (total area, 244.53 cm 2 ) by mainly improving the design of the hydrogenated intrinsic amorphous silicon (a-Si:H) on the rear side of the solar cell and the back reflector. A dense second intrinsic a-Si:H layer with an optimized thickness can improve the vertical carrier transport, resulting in an improved fill factor (FF). In order to reduce the plasmonic absorption at the back reflector, a low-refractive-index magnesium fluoride (MgF 2 ) is deposited before the Ag layer; this leads to an improved gain of short circuit current density (J sc ). In total, together with MgF 2 double antireflection coating and other fine optimizations during cell fabrication process, $1% absolute efficiency enhancement is finally obtained. A detailed loss analysis based on Quokka3 simulation is presented to confirm the design principles, which also gives an outlook of how to improve the efficiency further.

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In order to compensate the insufficient conductance of heterojunction thin films, transparent conductive oxides (TCO) have been used for decades in both-sides contacted crystalline silicon heterojunction (SHJ) solar cells to provide lateral conduction for efficient carrier collection. In this work, we substitute the TCO layers by utilizing the lateral conduction of c-Si absorber, thereby enabling a TCO-free design. A series resistance of 0.32 Ωcm 2 and a fill factor of 80.7% were measured for a TCO-free back-junction SHJ solar cell with a conventional finger pitch of 1.8 mm, thereby proving that relying on lateral conduction in the c-Si bulk is compatible with low series resistances. Achieving high efficiencies in SHJ solar cells with TCO-free front contacts requires suppressing deterioration of the passivation quality induced by direct metal-a-Si:H contacts and in-diffusion of metal into the a-Si:H layer. We show that an ozone treatment at the a-Si:H/metal interface suppresses the metal diffusion and improves the passivation without increasing the

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