High-quality 2D RP perovskite film grown along the out-of-plane direction is fabricated by the reverse-cool annealing strategy. 2D RP perovskite solar cells show high charge carrier extraction efficiency and small non-radiative open-circuit voltage loss. The champion efficiency of solar cells achieves 17.8%, which sustains 97.4% of the initial efficiency after 1000 h under the N₂ environment.

The figure highlights the interfacial engineering of perovskite solar cells (PSCs). Graphene quantum dots (GQDs) with different alkyl lengths adjust the energy level alignment at the SnO₂/perovskite interface or passivate the perovskite/HTL interface. Interface-engineered PSCs exhibit high conversion efficiencies due to the collaborative effects of efficient charge transfer and reduced trap density.

The study demonstrates that the incorporation of erbium chloride (ErCl₃) into tin-halide perovskite solar cells (THPSCs) effectively controls nucleation and crystallization, resulting in improved film morphology. This approach significantly enhances the efficiency and stability of THPSCs, leading to higher open-circuit voltage (V_OC) and power conversion efficiency (PCE) compared to traditional devices.

A cost-effective and long-term stable SSP film is designed and reported. It can effectively prevent over 99% lead leakage under different conditions with different device structures (p-i-n and n-i-p) and modules without affecting performance and stability.

An orthogonal solution-processable spray-coating method forms an n-type Cs₂SnI₆ double perovskite (Sn-DP) layer on a PEA_0.15FA_0.85SnI₃ perovskite layer (Sn-P), achieving 12.9% PCE and minimizing V_oc loss to 0.38 V. This architecture enhances electron transport, reduces defects, and offers 1000-h stability under continuous illumination, promising efficient, stable tin-based lead-free solar cells.

Thin-walled carbon nanotubes (TWCNT) were synthesized and assemblies demonstrated superior electric characteristics for perovskite solar cells (PSCs). We introduced low-molecular-weight PTAA infiltration into TWCNT electrodes to fulfill the porosity and modify the interface between TWCNT and perovskite layer. Furthermore,  a new design of TWCNT rear electrode hidden encapsulation technology enables the demonstration of the stable PSCs.

The use of toxic lead in high-efficiency perovskite photovoltaics raises significant sustainability concerns, particularly due to the risk of environmental contamination from lead leakage. Establishing sustainable lead management approaches, such as lead encapsulation and lead recycling, is crucial for minimizing lead's environmental impact and advancing the commercialization of perovskite photovoltaic materials.

This review explores lead-free alternatives such as Sn and Ge, environmentally friendly solvents, and green manufacturing processes for sustainable perovskite solar cells. Key strategies to enhance stability, minimize toxicity, and improve performance are discussed to guide the future of environmentally responsible photovoltaics.