Yu Chen

The physical adsorption of a self-assembled monolayer (SAM) onto an anchored layer introduces disordered stacking and a tangled dipole orientation at the hole-selective layer (HSL) surface, which affects the charge-transport dynamics and interface-driven energy loss in photovoltaic devices. Herein, we develop a collaborative strategy that combines stacking-order-driven interfacial dipole flipping with a chlorine-iodine exchange, achieved by depositing bismuth oxychloride (BiOCl) onto SAMs. This HSL exhibits a crystalline order characterized by dipole flipping and long-range periodic alignment in in-plane direction, driven by π-π interactions among carbazole units. It demonstrates enhanced stability against perovskite precursor solvents and thermal perturbations. The chlorine from BiOCl undergoes a chlorine-iodine exchange at the buried interface, modulating perovskite crystallization and weakening electron-phonon coupling. Our champion single-junction inverted perovskite solar cells (PSCs) achieve remarkable power conversion efficiencies (PCEs) of 27.25% (1.55 eV, 0.09 cm²) and 20.24% (1.85 eV, 0.09 cm²) with exceptional repeatability and operational stability. When employing SAMs/BiOCl as both HSL and interconnection layer, the champion perovskite-organic tandem solar cell (PO-TSC) attains an exceptional PCE of 28.14% (certified 27.84%) with steady power output of 27.86% (certified 27.59%). The device retains 90% of its initial efficiency under continuous maximum power point tracking with one-simulated-sun illumination over 600 hours.

Phase segregation is an inevitable phenomenon in wide‐bandgap perovskites, triggering nonradiative recombination and degrading device performance. Herein, we propose a molecular‐extrusion‐driven passivation strategy by introducing bromomethyl‐triphenylphosphonium bromide (TPB‐Br) into perovskite precursors to achieve halogen homogenization. This approach simultaneously passivates bulk and interfacial defects, significantly mitigates phase segregation, and suppresses nonradiative recombination in wide‐bandgap perovskites. As a result, we realize high‐quality wide‐bandgap perovskite films with high crystallinity, low defect density and released residual strain. Champion devices based on these films deliver impressive power conversion efficiencies (PCEs) of 23.63% in the 1.68 eV perovskite sub‐cell and 32.03% (1.05 cm ² ) in the perovskite/silicon tandem solar cell. More importantly, the unencapsulated devices maintained 90.1%, 81.2%, and 93.4% of their initial PCEs under long‐term storage, thermal‐aging, and light‐soaking for 1200 h, respectively. Our work demonstrates the advantage and feasibility of the synergistic passivation strategy in preparing high‐quality wide‐bandgap perovskite films and tandem solar cells.

Phase segregation is an inevitable phenomenon in wide‐bandgap perovskites, triggering nonradiative recombination and degrading device performance. Herein, we propose a molecular‐extrusion‐driven passivation strategy by introducing bromomethyl‐triphenylphosphonium bromide (TPB‐Br) into perovskite precursors to achieve halogen homogenization. This approach simultaneously passivates bulk and interfacial defects, significantly mitigates phase segregation, and suppresses nonradiative recombination in wide‐bandgap perovskites. As a result, we realize high‐quality wide‐bandgap perovskite films with high crystallinity, low defect density and released residual strain. Champion devices based on these films deliver impressive power conversion efficiencies (PCEs) of 23.63% in the 1.68 eV perovskite sub‐cell and 32.03% (1.05 cm ² ) in the perovskite/silicon tandem solar cell. More importantly, the unencapsulated devices maintained 90.1%, 81.2%, and 93.4% of their initial PCEs under long‐term storage, thermal‐aging, and light‐soaking for 1200 h, respectively. Our work demonstrates the advantage and feasibility of the synergistic passivation strategy in preparing high‐quality wide‐bandgap perovskite films and tandem solar cells.

Charge transport and nonradiative recombination loss at the buried interface are important factors, which limit the efficiency and stability of perovskite solar cells (PSCs). Herein, we screen a series of diphosphate Lewis‐base molecules, where N,N‐bis(diphenylphosphino)amine (N‐DPPM) with appropriate alkyl chains and multiple active sites not only can efficiently facilitate carrier transport but also coordinate with undercoordinated Pb²⁺ and interact with FA⁺ through N⋯H bond. These features prompt the formation of high‐quality perovskite films along (100)/(200) crystal facets. Interestingly, these oriented low‐Miller‐index crystal facets have approximately a twice‐increase in heterointerface energy and twice‐decrease in grain‐boundary energy, flattening grain‐boundary grooves, thereby reducing nanoscale physical voids and releasing residual stress. Consequently, the champion inverted PSCs exhibit impressive power conversion efficiencies of 26.80%, 26.18%, and 20.59% for narrow‐bandgap (1.55 eV), large‐area (0.5 cm²), and wide‐bandgap (1.73 eV) devices, respectively. Meanwhile, the unencapsulated devices exhibit excellent stability after long‐term storage, thermal‐aging, or light‐soaking.

Durable shelf-life of precursor solutions is crucial for obtaining high-quality and stable perovskite films, which significantly affect the efficiency and stability of perovskite solar cells (PSCs). However, iodides in perovskites are easily oxidized by oxygen, especially under light exposure, reducing the shelf-life of precursor solutions and compromising perovskite films. Herein, we introduce sodium thiosulfate (ST) into perovskite inks to in situ tailor the crystallization of perovskites and suppress oxidation of iodides. As expected, this ST strategy effectively suppresses the iodide oxidation, and inhibits phase transitions and separation, thereby obtaining high-quality perovskite films with enhanced high crystallinity and reduced non-radiative recombination. Interestingly, the shelf-life of precursor solutions was extended over 60 days, and no phase transition can be found in perovskite films during 60 days of 1 sun light exposure. As a result, the champion ST-treated device achieves a PCE of 25.25% with a minimal voltage deficit of 0.35 V. More importantly, the unencapsulated devices demonstrate excellent long-term storage, thermal and light-soaking stability, delivering 93%, 85% and 85% of their original efficiencies after aging, respectively. This work provides an effective approach to extend the shelf-life of precursor solutions and improve the efficiency and operational stability of PSCs.

Obtaining high‐quality perovskite films is crucial for reducing non‐radiative recombination and improving device performance. As reported, the crystallization process of perovskite films can be effectively tailored by introducing multifunctional additives. In this work, polyvinyl pyrrolidone (PVP) with varying degrees of polymerization (DP) values (K15, K30, and K90) are systematically screened and utilized as an additive to regulate defect density and control the crystallization process of perovskite films. This regulation is achieved through coordination interactions between perovskites and their multi‐carbonyl groups of PVP. Among the selected polymers, the K30 carbonyl polymer exhibits a suitable viscosity and bind strength, which facilitated a significant delay in the intermediate phase transition and accelerated nucleation. As a result, high‐quality perovskite films with enhanced crystallinity, prolonged PL lifetime, and no residual PbI ₂ are achieved. The K30‐treated MA‐free device demonstrated a PCE of 24.16% with a remarkable V _OC of 1.2 V. Moreover, this strategy can be extended to RbCsFAMA quadruple‐cation perovskite films, delivering an impressive PCE of 25.35% with a minimal V _OC deficit of 0.35 V. This work provides an effective approach to modulate the crystal growth of perovskite films and highlights the significance of the DP values for polymeric additives.

As one of the important components of high-effi-ciency perovskite/silicon series devices, widebandgap (WBG) perovskite solar cells (PSCs) have been suffering from serious carrier transport barriers and huge open-circuit voltage deficit derived from non-radiative recombination, especially at the buried interface that are often overlooked. Herein, we combined cationic and anion passivation strategies via ammonium tetra-n-butyl tetrafluoroborate (TBABF4) pre-treating the buried interface. Theoretical calculation predicts that the tetrabutylammonium (TBA+) organic cations and (tetrafluoroborate) BF4− anions can easily interact with charged interfacial defect. Characterizations further confirm the enhancement of carrier transport performance and decrease in defect density upon TBABF4 pre-treatment. Consequently, a power conversion efficiency of 21.35% with an ultrahigh filling factor of 84.12% is obtained for 1.68 eV-WBG inverted PSCs. In addition, the device with TBABF4 pretreatment demonstrates excellent shelf, thermal, and operational stability.

Rational regulation of Me‐4PACz/perovskite interface has emerged as a significant challenge in the pursuit of highly efficient and stable perovskite solar cells (PSCs). Herein, an organometallic molecule of aluminum glycinate (AG) that contained amine (‐NH₂) and aluminum hydroxyl (Al‐OH) groups is developed to tailor the buried interface and minimize interface‐driven energy losses. The Al‐OH groups selectively bonded with unanchored O═P‐OH and bare NiO‐OH to optimize the surface morphology and energy levels, while the ‐NH₂ group interacted specifically with Pb²⁺ to retard perovskite crystallization, passivate buried Pb‐related defects, and release residual interface stress. These interactions facilitate the interface carrier extraction and reduce interface‐driven energy losses, thereby realizing a balanced charge carrier transport. Consequently, AG‐modified narrow bandgap (1.55 eV) PSC demonstrates an efficiency of 26.74% (certified 26.21%) with a fill factor of 86.65%; AG‐modified wide bandgap (1.785 eV) PSC realizes 20.71% champion efficiency with excellent repeatability. These PSCs maintain 91.37%, 91.92%, and 92.00% of their initial efficiency after aging in air atmosphere, the nitrogen‐filled atmosphere at 85 °C, and continuously tracking at the maximum power‐point under one‐sun illumination (100 mW cm⁻²) for 1200 h, respectively.

Carrier transport and recombination at the buried interface of perovskite have seriously restricted the further development of inverted perovskite solar cells (PSCs). Herein, an interfacial dipolar chemical bridge strategy to address this issue is presented. 2-(Diphenylphosphino) acetic acid (2DPAA) is selected as the linker to reconstruct the interfacial dipole, which effectively enlarges the interfacial dipole moment to 5.10 D and optimizes to a positive dipole orientation, thereby accelerating vertical hole transport, suppressing nonradiative recombination and promoting the perovskite crystallization. The champion inverted device yields a high power conversion efficiency (PCE) of 26.53% (certified 26.02%). Moreover, this strategy is extended to the wide-bandgap perovskite and large-area devices, which delivers high PCEs of 22.02% and 24.11%, respectively. The optimized devices without encapsulation also demonstrate great long-term shelf and operational stability. Our work highlights the importance of interfacial dipole moment and orientation at the buried interface to realize efficient and stable inverted PSCs.