Zaiwei Wang

Mixed tin–lead (Sn–Pb) perovskites are essential for high‐efficiency tandem solar cells, typically employing a formamidinium (FA)‐dominated composition with a small amount of MA. However, the regulatory role of such A‐site mixing on mixed Sn–Pb perovskite properties remains underexplored. This work demonstrates that engineering the thermodynamic landscape of mixed Sn–Pb perovskite formation enables simultaneous regulation of phase homogeneity and defect chemistry. By controllably incorporating methylammonium (MA) cations, the crystallization kinetics are modulated to promote uniform nucleation, suppress Sn–Pb phase segregation, and inhibit Sn ²⁺ oxidation, thereby mitigating non‐radiative recombination losses. As a result, mix tin–lead perovskite solar cells achieved a certified power conversion efficiency (PCE) of 23.90%. By leveraging the improved compositional homogeneity and suppressed defect density, the optimized tin–lead absorber is further integrated into two‐terminal monolithic all‐perovskite tandem devices, delivering a PCE of 30.13% (certified 29.57%). The unencapsulated tandem devices maintained 90% of its initial PCE after 495 h of maximum power point operation under simulated one‐sun illumination.

Self-assembled monolayers (SAMs) have boosted perovskite solar cell (PSCs) efficiencies, but their ultrathin nature causes structural vulnerability under outdoor solar illumination, particularly in the ultraviolet (UV) regime, limiting long-term operation and practical deployment of PSCs. Extensive experiments with ab initio molecular dynamics reveal conventional SAMs undergo rapid structural degradation under UV irradiation, leading to molecular desorption and film collapse. Here, we introduced a SAM featuring dual-dimensional reinforcement. Vertically, multiple anchoring sites and flexible π-conjugated framework enable strong adhesion to bidirectional adjacent layers, providing exceptional interfacial UV durability. Horizontally, intrinsically structural stability and interlocked networks further prevent the film collapse caused by high-energy UV invasion. The champion device achieved a power conversion efficiency of 27.10% (certified 26.90%). After 2100 hours of maximum power point tracking (ISOS-L-2) at 65 °C, only 2% of the efficiency was lost. Moreover, the devices retained 86.7% of initial PCE after 2200 hours under high-intensity UV light (1.73-fold the intensity of natural sunlight), and 90.5% after 2035 hours of outdoor exposure, representing the highest UV stability of SAM-based PSCs.

The development of high-performance narrow-bandgap tin-lead (Sn-Pb) perovskite solar cells (PSCs) is fundamental to surpassing the Shockley-Queisser limit via all-perovskite tandem configurations. Nevertheless, the vulnerability of Sn²⁺ to oxidation in Sn-Pb perovskite films and devices remains a formidable obstacle to achieving superior film quality and competitive power conversion efficiency (PCE). Here, we introduce a bio-inspired antioxidant engineering strategy employing gallic acid (GA) as a dopant and tannic acid (TA) as a surface passivator to separately stabilize the perovskite bulk and interface. GA, a small antioxidant molecule, localizes at the grain boundaries to impart oxidation resistance and suppress the formation of excess SnI₂ impurities. TA, with its larger molecular framework, resides at the film surface to form a robust passivation layer that hinders oxygen intrusion while establishing a dipole that facilitates interfacial charge transfer. The dual-molecule synergy significantly enhances film oxidative stability against both intrinsic (precursor degradation) and extrinsic (neutral oxygen and superoxide) stimuli. Consequently, the Sn-Pb PSCs achieve a champion PCE of 23.46%, enabling a remarkable 29.95% (certified 29.44%) efficiency in monolithic all-perovskite tandems.

Incorporating 4Cl-BZS into FAPbBr ₃ perovskites relieves lattice strain and suppresses the detrimental yellow δ-phase. The optimized device architecture delivers stabilized α-phase perovskite solar cells with superior PCE of 10.57%.

A multifunctional zwitterionic additive regulates crystallization, passivates defects, suppresses ion migration and relaxes residual stress in inverted perovskite solar cells, achieving 26.69% certified efficiency and excellent stability.

All‐perovskite multi‐junction solar cells, integrating multiple light absorbers with complementary bandgaps, provide an effective pathway to break through the power conversion efficiency (PCE) limits of single‐junction photovoltaics. However, they are still in the infancy stage. Several critical challenges include the facile oxidation of Sn ²⁺ and difficult‐to‐control crystallization dynamics in narrow‐bandgap perovskites, as well as significant open‐circuit voltage deficits in wide‐bandgap perovskites. These intrinsic limitations result in experimental PCEs far below their theoretical values, highlighting the urgent need for a systematic review in this field. Herein, research progress are comprehensively summarized in all‐perovskite multi‐junction solar cells, elucidating the underlying mechanisms of performance losses. Furthermore, various optimization strategies are critically discussed for perovskite absorbers, charge transport materials, and interconnecting layers. Finally, future perspectives for this emerging photovoltaic technology are presented.

All‐inorganic tin (Sn)‐containing perovskites have emerged as highly promising photovoltaic materials for single‐junction and tandem perovskite solar cells (PSCs), owing to their reduced toxicity, optimal narrow bandgap, and superior thermal stability. Since their initial exploration in 2012, significant advancements have been achieved, with the highest efficiencies of single‐junction and tandem devices now surpassing 17% and 22%, respectively. Nevertheless, the intrinsic challenges associated with the oxidation susceptibility of Sn²⁺ and the uncontrolled crystallization dynamics impede their further development. Addressing these issues necessitates a comprehensive and systematic understanding of the degradation mechanisms inherent to all‐inorganic Sn‐containing perovskites, as well as the development of effective mitigation strategies. This review provides a detailed overview of the research progress in all‐inorganic Sn‐containing PSCs, with a particular focus on the basic properties and degradation pathways of both pristine Sn and mixed Sn‐Pb perovskites. Furthermore, various strategies to improve the efficiency and stability of Sn‐containing PSCs are thoroughly discussed. Finally, the existing challenges and perspectives are provided for further improving the photovoltaic performance of eco‐friendly PSCs.