Self-assembled monolayers (SAMs) have become pivotal in achieving high-performance perovskite solar cells (PSCs) and organic solar cells (OSCs) by significantly minimizing interfacial energy losses. In this study, we propose a co-adsorb (CA) strategy employing a novel small molecule, 2-chloro-5-(trifluoromethyl)isonicotinic acid (PyCA-3F), introducing at the buried interface between 2PACz and the perovskite/organic layers. This approach effectively diminishes 2PACz’s aggregation, enhancing surface smoothness and increasing work function for the modified SAM layer, thereby providing a flattened buried interface with a favorable heterointerface for perovskite. The resultant improvements in crystallinity, minimized trap states, and augmented hole extraction and transfer capabilities have propelled power conversion efficiencies (PCEs) beyond 25% in PSCs with a p-i-n structure (certified at 24.68%). OSCs employing the CA strategy achieve remarkable PCEs of 19.51% based on PM1:PTQ10:m-BTP-PhC6 photoactive system. Notably, universal improvements have also been achieved for the other two popular OSC systems. After a 1000-hour maximal power point tracking, the encapsulated PSCs and OSCs retain approximately 90% and 80% of their initial PCEs, respectively. This work introduces a facile, rational, and effective method to enhance the performance of SAMs, realizing efficiency breakthroughs in both PSCs and OSCs with a favorable p-i-n device structure, along with improved operational stability.

Wide-bandgap (WBG; >1.65 electron volts) perovskites based on iodine-bromine (I-Br) mixed halides are critical components of perovskite-based tandem solar cells (TSCs). However, the uncontrolled crystallization dynamics of Br-rich species lead to reduced grain sizes and high defect densities in WBG perovskite films. Herein, a multifunctional additive 3,4,5-trifluorobenzamide (TFBZ) was introduced to enhance the crystallinity and passivate defects of the methylammonium (MA)–free WBG perovskite films. The TFBZ demonstrates superior passivation capability compared to benzamide, effectively mitigating both iodine vacancies and undercoordinated Pb ²⁺ defects via fluorine-enhanced interactions. In addition, the fluorine substituents in TFBZ could form N–H···F hydrogen bonds with formamidinium iodide to retard the crystallization rate of the perovskite. This proposed method is effective in defect passivation and crystal growth modulation for both 1.67– and 1.79–electron volt MA-free WBG perovskites, enabling the fabrication of MA-free all-perovskite TSCs with an encouraging power conversion efficiency of 29.01% (certified at 28.52%).

All-perovskite tandem solar cells (APTSCs) offer the potential to surpass the Shockley-Queisser limit of single-junction solar cells at low cost. However, high-performance APTSCs contain unstable methylammonium (MA) cation in the tin-lead (Sn-Pb) narrow bandgap subcells. Currently, MA-free Sn-Pb perovskite solar cells (PSCs) show lower performance compared with their MA-containing counterparts. This is due to the high trap density associated with Sn²⁺ oxidation, which is exacerbated by the rapid crystallization of MA-free Sn-containing perovskite. Here, a multifunctional additive rubidium acetate (RbAC) is proposed to passivate Sn-Pb perovskite. We find that RbAC can suppress Sn²⁺ oxidation, alleviate microstrain, and improve the crystallinity of the MA-free Sn-Pb perovskite. Consequently, the resultant Sn-Pb PSCs achieve a power conversion efficiency (PCE) of 23.02%, with an open circuit voltage (Voc) of 0.897 V, and a filling factor (FF) of 80.64%, and more importantly the stability of the device is significantly improved. When further integrated with a 1.79-electron volt MA-free wide-bandgap PSC, a 29.33% (certified 28.11%) efficient MA-free APTSCs with a high Voc of 2.22 volts is achieved.

Advances in improving the operational lifetime of highly efficient organic photovoltaic (OPV) and understanding photo-degradation mechanisms in molecular level are currently limited, especially on the promising inverted OPV, posing critical challenges to commercialization. Here, we demonstrate a radical scavenger (3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid) capped ZnO (BHT@ZnO) nanoparticles as the electron transport layer providing effective surface oxygen vacancy passivation and reactive radical capture capability. Encouragingly, this BHT@ZnO-based empowered device achieves a record inverted OPV efficiency of 19.47% (Certificated efficiency: 18.97%). The devices demonstrate light soaking-free behavior, long-term stability under ISOS-D-1 (94.2% PCE retention after 8904 h in ambient) and ISOS-L-1 testing protocol (81.5% PCE retention after 7724 h in MPP). More importantly, we elucidate detailed degradation mechanism in OPV involving selectively catalytic degradation of donor and acceptor by superoxide and hydroxyl radicals, respectively, as well as the degradation pathway of polymer donor upon radiation exposure. Performance enhancement and mechanism comprehension provide strong support for the development of OPV technology.

The primary challenge in commercializing perovskite solar cells (PSCs) mainly stems from fragile and moisture-sensitive nature of halide perovskite materials. In this study, we propose an asynchronous cross-linking strategy. A multifunctional cross-linking initiator, divinyl sulfone (DVS), is firstly pre-embedded into perovskite precursor solutions. DVS, also as a special co-solvent, facilitates intermediate-dominated perovskite crystallization manipulation, favouring formamidine-DVS based solvate transition. Subsequently, DVS-embedded perovskite as-cast films are post-treated with a nucleophilic reagent, glycerinum, to trigger controllably three-dimensional co-polymerization. The resulting cross-linking scaffold provides enhanced water-resistance, releases residual tensile strain, and suppresses deep-level defects. We achieve a maximum efficiency over 25% (certified 24.6%) and a maximum V_OC of 1.229 V, corresponding to mere 0.30 V deficit, reaching 97.5% of the theoretical limit, which is the highest reported in all perovskite systems. This strategy is generally applicable with enhanced efficiencies approaching 26%. All-around protection significantly improves PSC’s operational longevity and thermal endurance.