Perovskite Solar Cells (PSCs) have achieved power conversion efficiencies (PCEs) comparable to established technologies, but their stability in real-life working conditions -including exposure to moisture, heat and light -has still not been decisively demonstrated. Encapsulation of the cells is vital for increasing device lifetime, as well as shedding light on the intrinsic degradation process of the active layers. Here we compare different sealing protocols applied to large area cells (1 cm 2 , average PCE 13.6%) to separate the extrinsic degradation, due to the external environment, from the intrinsic one, due to the materials themselves. Sealing methods were tested against accelerated life-time tests -damp-heating, prolonged heating and light-soaking. We thus developed and tested a novel sealing procedure that makes PSCs able to maintain a stabilized 10% PCE after heat, light and moisture stress.

A novel configuration for high-performant perovskite/silicon tandem solar cells is demonstrated using a facile mechanical stacking of the sub-cells. The resulting champion perovskite/silicon tandem solar cell exhibits a stabilized efficiency of 25.9% over an active area of 1.43 cm 2 .

As the hole transport layer (HTL) for perovskite solar cells (PSCs), poly(3‐hexylthiophene) (P3HT) has been attracting great interest due to its low‐cost, thermal stability, oxygen impermeability, and strong hydrophobicity. In this work, a new doping strategy is developed for P3HT as the HTL in triple‐cation/double‐halide ((FA1−x−yMAxCsy)Pb(I1−xBrx)3) mesoscopic PSCs. Photovoltaic performance and stability of solar cells show remarkable enhancement using a composition of three dopants Li‐TFSI, TBP, and Co(III)‐TFSI reaching power conversion efficiencies of 19.25% on 0.1 cm2 active area, 16.29% on 1 cm2 active area, and 13.3% on a 43 cm2 active area module without using any additional absorber layer or any interlayer at the PSK/P3HT interface. The results illustrate the positive effect of a cobalt dopant on the band structure of perovskite/P3HT interfaces leading to improved hole extraction and a decrease of trap‐assisted recombination. Non‐encapsulated large area devices show promising air stability through keeping more than 80% of initial efficiency after 1500 h in atmospheric conditions (relative humidity ≈ 60%, r.t.), whereas encapsulated devices show more than >500 h at 85 °C thermal stability (>80%) and 100 h stability against continuous light soaking (>90%). The boosted efficiency and the improved stability make P3HT a good candidate for low‐cost large‐scale PSCs.

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Implementation of resonant nanoparticles (NPs) for improving performance of organometal halide perovskites solar cells is highly prospective approach, because it is compatible with the solution processing techniques used for any organic materials. Previously, resonant metallic NPs have been incorporated into perovskite solar cells for better light absorption and charge separation. However, high inherent optical losses and high reactivity of noble metals with halides in perovskites are main limiting factors for this approach. Incidentally, low‐loss and chemically inert resonant silicon NPs allow for light trapping and enhancement at nanoscale, being suitable for thin film photovoltaics. Here photocurrent and fill‐factor (FF) enhancements in meso‐superstructured perovskite solar cells, incorporating resonant silicon NPs between mesoporous TiO2 transport and active layers, are demonstrated. This results in a boost of device efficiency up to 18.8% and FF up to 79%, being a record among the previously reported values on NPs incorporation into CH3NH3PbI3 perovskite‐based solar cells. Theoretical modeling and optical characterization reveal the significant role of Si NPs for increased light absorption in the active layer rather than for better charge separation. The proposed strategy is universal and can be applied in perovskite solar cells with various compositions, as well as in other optoelectronic devices.