The performance of perovskite solar cells with inverted polarity ( p-i-n ) is still limited by recombination at their electron extraction interface, which also lowers the power conversion efficiency (PCE) of p-i-n perovskite-silicon tandem solar cells. A ~1 nm thick MgF x interlayer at the perovskite/C 60 interface through thermal evaporation favorably adjusts the surface energy of the perovskite layer, facilitating efficient electron extraction, and displaces C 60 from the perovskite surface to mitigate nonradiative recombination. These effects enable a champion V oc of 1.92 volts, an improved fill factor of 80.7%, and an independently certified stabilized PCE of 29.3% for a ~1 cm 2 monolithic perovskite-silicon tandem solar cell. The tandem retained ~95% of its initial performance following damp-heat testing (85 Celsius at 85% relative humidity) for > 1000 hours.

Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices.

Yang and co-workers reported a dual-function, low-cost, high-performance titanium-nitride-based passivating contact for silicon solar cells. By the implementation of electron-conductive titanium nitride contact, which acts simultaneously as a surface passivating layer and metal electrode, a silicon solar cell with an efficiency of 20% is achieved using a simplified fabrication process. This work also expands the pool of available electron transport materials, from metal oxides to metal nitrides, for photovoltaic devices.

High carrier recombination loss at the contact regions has become the dominant factor limiting the power conversion efficiency (PCE) of crystalline silicon (c‐Si) solar cells. Dopant‐free carrier‐selective contacts are being intensively developed to overcome this challenge. In this work, vanadium oxide (VOx) deposited by atomic layer deposition (ALD) is investigated and optimized as a potential hole‐selective contact for c‐Si solar cells. ALD VOx films are demonstrated to simultaneously offer a good surface passivation and an acceptable contact resistivity (ρc) on c‐Si, achieving a best contact recombination current density (J0) of ≈40 fA cm−2 and a minimum ρc of ≈95 mΩ.cm2. Combined with a high work function of 6.0 eV, ALD VOx films are proven to be an effective hole‐selective contact on c‐Si. By the implementation of hole‐selective VOx contact, the state‐of‐the‐art PCE of 21.6% on n‐type c‐Si solar cells with a high stability is demonstarted. These results demonstrate the high potential of ALD VOx as a stable hole‐transport layer for photovoltaic devices, with applications beyond c‐Si, such as perovskite and organic solar cells.

High quality carrier-selective contacts with suitable electronic properties are a prerequisite for high power conversion efficiency (PCE) photovoltaic devices. In this work, an efficient electron-selective contact, titanium oxynitride (TiOxNy), is developed for crystalline silicon (c-Si) and organic photovoltaic devices. Atomic-layer deposited TiOxNy is demonstrated to be highly conductive with a proper work function (4.3 eV) and a wide band gap (3.4 eV). Thin Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))