Non-radiative recombination losses in non-fullerene acceptors (NFAs) represent a critical bottleneck limiting the open-circuit voltage (Voc) and power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, we report a molecular design strategy that harnesses luminescent-carbazole linkage site isomerism to suppress non-radiative recombination. Two carbazole-functionalized NFAs, QxCz‑C and QxCz‑N, were designed and synthesized. Theoretical calculations reveal that QxCz‑C adopts a coplanar conformation, whereas the carbazole unit in QxCz‑N is oriented nearly perpendicular to the main chain. Upon incorporating QxCz‑C as a minor guest into the host material BTP‑eC9, a favorable mixed phase is formed, accompanied by efficient energy transfer from the guest to the host. The photoluminescence quantum yield of the blend acceptor is significantly enhanced, effectively suppressing electron‑phonon coupling, thereby reducing non‑radiative recombination loss and improving Voc. Simultaneously, guest incorporation optimizes molecular packing order and active layer morphology, facilitating exciton dissociation and charge transport. Consequently, the PM6:BTP‑eC9:QxCz‑C device achieves a PCE of 20.53%. The generality of this strategy is further validated in the D18:L8‑BO system, delivering an excellent PCE of 21.10%. This work establishes a quantitative "connectivity topology-molecular conformation-non-radiative loss" structure-property relationship and provides a generalizable approach to overcoming the voltage bottleneck in OSCs.

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.

The performance and operational stability of inverted organic solar cells (OSCs) are often limited by charge recombination and interfacial instability at the electron transport layer (ETL). To address this, we designed two fullerene-based self-assembled monolayers (SAMs)-C2-PA and 4EG-PA-as interfacial modifiers for zinc oxide (ZnO). Systematic comparisons reveal that the tetra(ethylene glycol) linker in 4EG-PA induces a denser and more uniform SAM morphology than the alkyl chain in C2-PA, which more effectively passivates the polar ZnO surface. This superior molecular packing translates into a champion power conversion efficiency of 19.46%. More critically, transient absorption spectroscopy (TAS) provides direct evidence that the 4EG-PA-modified interface facilitates the formation of a favorable charge-transfer state, which not only promotes electron extraction but also enhances hole transfer efficiency from the acceptor to the donor, thereby suppressing non-geminate recombination. Concurrently, the dense SAM acts as a robust buffer, improving the thermodynamic compatibility with the active layer and inhibiting its deleterious reaggregation. This dual mechanism-enhanced charge extraction and optimized interfacial morphology-underpins the exceptional operational stability, with devices retaining 84% of their initial performance after 2000 h. Our work elucidates the critical link between SAM molecular structure, interfacial properties, and device longevity, providing a strategic blueprint for future interfacial material design.

Constructing 2D/3D perovskite heterojunction is an effective method to improve performance and stability of perovskite solar cells(PSCs),while the quantum wellin 2D perovskites hinders carrier transport.To address this issue,π-conjugated semiconducting ligands have been introduced to enhance carrier-transfer capabil-ity of 2D perovskites.Here,two triphenylamine(TPA)-based ligands are specifically designed through π-extension with a fused(N-TPEAI)or covalently linked(P-TPEAI)benzene ring.For the first time,TPA semiconductor-based ligands have been incorporated to construct 2D/3D PSCs with poly[bis(4-phenyl)(2,4,6-tri-methylphenyl)amine](PTAA)as hole-transport materials(HTMs).Combined experimental and computational analyses reveal that this π-conjugation extension strategy proves to be effective in strengthening intermolecular interactions both between the adjacent spacer cations within 2D perovskites and at perovskite/PTAA interfaces,particularly in the case of P-TPEAI.Ultimately,the resultant 2D/3D PSCs employing P-TPEAI achieve an outstanding efficiency of 26.13％,which,to the best of our knowledge,is the highest value reported for 2D/3D PSCs incorporating PTAA HTMs.Moreover,benefiting from the robustness of both 2D perovskites and PTAA,the correspond-ing devices also exhibit excellent light-heat stability,meeting ISOS-L-2 protocol.These findings provide important guidelines for future design of organic spacers in advancing efficient and robust PSCs and related optoelectronic devices.

Solution-processed antisolvent-free perovskites (AFPs) are promising candidates for scalable photovoltaic (PV) production. However, achieving high-quality AFP films typically requires stringent processing conditions, limiting reliability in large-scale manufacturing. Here, we employ machine learning (ML) to identify solvent additives that modulate the ambient temperature (TA) processing window. This approach successfully reveals an additive that enables a record-wide TA window, from 16 degrees C to 28 degrees C, with constantly high power conversion efficiencies (PCEs) exceeding 24%. Mechanistically, in contrast to the previously reported solvent-lead iodide (PbI2) interaction model, we demonstrate that anchoring formamidinium (FA) cations with the additive to form stable adducts is essential. This interaction effectively suppresses crystallization kinetics, facilitating uniform precursor distribution and high-quality film formation. Importantly, these results challenge the conventional crystallization paradigm for solution-processed perovskites, which emphasizes rapid and complete nucleation during the initial stage of film deposition. Instead, we find that a uniform distribution of precursor ions, even without any nucleation, is sufficient to achieve high-quality perovskite thin films. This work not only demonstrates an effective ML-guided solvent selection strategy but also provides fundamental insight into the primary crystallization requirements for scalable production of high-quality perovskite PV thin films.

Perovskite solar cells (PSCs) have emerged as a leading photovoltaic technology, thanks to their remarkable power conversion efficiency (PCE) and cost-effectiveness. Despite achieving PCEs over 26%, the interface between the perovskite layer and the electron transport layer continues to be a significant barrier to achieving even higher PCEs and ensuring long-term stability. This study presents a molecular engineering strategy through stereoisomeric modulation of thiourea derivatives, comparing N,N '-diphenylthiourea (DPT) with its structural isomer 1,1-DPT as interfacial passivators. The distinct spatial configurations of these isomers fundamentally govern their defect-passivation capabilities. The 1,1-DPT isomer, featuring optimized bidentate coordination geometry, demonstrates superior binding affinity with undercoordinated Pb2+ defects through dual S-Pb and N-Pb interactions. Both device testing and density functional theory analyses confirm that these stronger bonding interactions lead to a reduction in defect densities. Benefitting from the exceptional passivation properties of 1,1-DPT, the device achieved an impressive efficiency of 25.86% coupled with superior operational stability. This work establishes a new paradigm for precision molecular design in PSC engineering, demonstrating that strategic manipulation of isomer-specific adsorption configurations can synergistically address both structural and electronic defects at critical interfaces.

Organic solar cells (OSCs) have garnered extensive attention due to their advantage of low cost and lightweight properties. However, owing to the complex interplay between excitons and charge carriers, the intrinsic energy loss pathways and performance-limiting factors in OSCs remain poorly understood. Herein, we established a comprehensive opto-electro-thermal (OET) model to quantify the exciton- and carrier-related thermodynamic loss mechanisms in organic photovoltaics, and identified seven inherent energy loss channels in OSCs. To identify the key bottlenecks limiting device performance, we further systematically explored the influences of temperature and key electrical parameters on device performance. The results reveal that operating temperature and carrier mobility impose opposite impacts on exciton dissociation and carrier recombination behaviors, and balancing these two loss types enables optimized OSC performance. Guided by these insights, we experimentally fabricated BHJ and LBL-type OSCs achieving a power conversion efficiency (PCE) of 19.7% and 19.9%, respectively. Furthermore, our results demonstrate that a PCE exceeding 22.2% can be expected for OSCs through the integration of rational material design and working temperature management. This study is critical for an in-depth understanding of OET-coupled physics in exciton- and carrier-mixed devices and provides a theoretical guide for the design of high-performance OSCs.

Quasi‐homojunction (QHJ) organic solar cells (OSCs) offer a promising alternative architecture that combines the advantages of bulk heterojunction (BHJ) and homojunction (HJ) designs. By blending a minimal fraction of donor material (a few wt%) into a nonfullerene acceptor matrix, QHJ devices can be designed to achieve efficient charge separation and transport while avoiding the morphological complexity and instability of BHJs. This study demonstrates that Y6‐based QHJ OSCs, incorporating only 4 wt% donor content, achieve a power conversion efficiency of 7.1%. This performance enhancement is enabled by replacing the PEDOT:PSS anode with a novel self‐assembled monolayer anode, which induces vertical phase separation, positioning the donor polymer at the anode interface to enhance charge extraction. The optimized vertical morphology not only facilitates efficient charge transport but also ensures excellent stability, maintaining consistent performance across active layer thicknesses of 55–180nm. This highlights the potential of QHJ architecture to combine the simplicity of HJ with the performance advantages of BHJ.

Carbon-based, fully printable hole-transport-layer-free mesoscopic perovskite solar cells (p-MPSCs) offer a low-cost, scalable photovoltaic technology, yet suffer from efficiency losses due to non-radiative recombination at electron-selective interface. Here, we design geometrically asymmetric zwitterions, featuring a bulky charge-dispersed triphenylphosphonium cation and a small charge-concentrated sulfonate anion linked by an alkyl chain, to weaken intermolecular and intramolecular charge attraction, thereby constructing a permanent dipole interlayer that mitigates such recombination. By extending the alkyl spacer and introducing methyl substituents on triphenylphosphonium, the optimized zwitterion, 4-(tri-p-tolylphosphonio)butane-1-sulfonate (4MePS), achieves an ultrahigh dipole moment of 14.92 Debye. 4MePS strongly interacts with both perovskite and TiO2 to form surface dipoles, drastically lowering their work functions by 0.42 and 0.54 eV, respectively. Comprehensive characterizations confirm that 4MePS suppresses non-radiative recombination and accelerates charge extraction in p-MPSCs. Consequently, 4MePS-treated p-MPSCs deliver a champion power conversion efficiency (PCE) of 23.3% (vs. 21.8% for control) and a minimodule efficiency of 20.2% over 57.3 cm2, among the highest reported for p-MPSCs. Encapsulated devices retain 90% of their initial PCE after 1200 hours of maximum power point tracking under 1‑sun illumination at 55 ± 5 °C. This work establishes a charge density-asymmetric molecular design strategy for engineering interfacial dipoles toward high-performance perovskite devices.

Monolithic all-perovskite tandem solar cells (TSCs) offer a route beyond single-junction efficiency limits through band-gap engineering. However, stability is hampered by hygroscopic degradation and phase segregation of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), the most common hole-transport material for narrow band-gap subcells. Here, we investigate the interface-mediated crystallization dynamics in mixed tin-lead (Sn-Pb) perovskites through in situ studies. We find that solvent-underlayer synergetic interactions with PEDOT:PSS induce metastable phase segregation during crystallization. Replacing PEDOT:PSS with a phenothiazine-functionalized interface facilitates direct phase transition and achieves preferential (100) orientation, yielding high-quality perovskite films. This enables a single-junction narrow band-gap subcell with 23.2% efficiency. Furthermore, we apply a hybrid interlayer integrating thiol and phosphonic acid anchoring groups on SnO2/Au, achieving a dense interconnecting layer for monolithic all-perovskite TSCs with 29.1% efficiency. The device retains 90% of the initial efficiency over 800 h of maximum power point tracking under simulated 1-sun illumination at 40°C, demonstrating robust operational stability.

Semitransparent perovskite solar cells (ST-PSCs) for building-integrated photovoltaics (BIPV) face severe performance trade-offs when the absorber is thinned to achieve high average visible transmittance (AVT). Thinner absorbers lead to a higher density of interfacial defects, stronger optical scattering, and faster thermal degradation resulting from inefficient heat dissipation. To overcome these interconnected challenges, we introduce a pharmacophore-guided molecular design strategy using dexamethasone (Dex). The conformationally rigid scaffold of Dex spatially arranges carbonyl, hydroxyl, and 9 alpha-fluoro groups to enable multi-point molecular recognition at perovskite heterointerfaces. This precise functional group arrangement simultaneously passivates Pb2+ and halide defects while enabling high-quality, pinhole-minimized films. Meanwhile, an inward-oriented interfacial dipole optimizes band alignment and accelerates hole extraction, while concurrently enhancing thermal transport by reducing the interfacial thermal resistance. Density functional theory (DFT) and opto-electro-thermal (OET) modeling quantitatively demonstrate suppressed nonradiative recombination and interfacial heat generation. Consequently, optimized ST-PSCs with similar to 150 nm absorbers achieve a high open-circuit voltage of 1.165 V and power conversion efficiency of 15.26% at 20.88% AVT (LUE approximate to 3.19%), with T-80 > 1000 h at 80 degrees C in nitrogen. This work establishes pharmacophore-guided interfaces as a versatile materials design paradigm for synchronizing optical, electrical, and thermal management in ultrathin PVs.

Perovskite solar cells (PSCs) are considered a promising next-generation photovoltaic technology due to their high power conversion efficiency and cost-effective manufacturing. However, their practical application is hindered by the lack of suitable encapsulation materials that protect against environmental degradation while maintaining compatibility with the chemical and thermal fragility of metal halide perovskites. Conventional encapsulation materials, such as ethylene-vinyl acetate (EVA) copolymer and polyolefin elastomer (POE) films, rely on high processing temperatures (>140 degrees C) and reactive additives, which can damage PSCs during encapsulation. Developing environmentally friendly, low-temperature encapsulation materials tailored to PSCs is therefore critical to advancing their industrialization. Here, we present a bio-based fluorinated polyether ester (PTFF) polymer film as a recyclable and nondestructive encapsulation solution for PSCs. PTFF, synthesized mainly from biomass-derived monomers, achieves additive-free adhesion through noncovalent interactions and features a tunable glass transition temperature (<80 degrees C) for low-temperature hot-pressing. Encapsulated PSCs demonstrate excellent thermal and moisture stability, retaining >80% efficiency after 600 hours under damp heat conditions (85 degrees C, RH = 85%). Moreover, PTFF is easily recyclable via simple physical delamination methods, maintaining its adhesion performance after recovery. This work highlights a sustainable encapsulation strategy tailored to PSCs, addressing their unique stability and environmental requirements, and provides a pathway toward scalable and sustainable photovoltaic module production.

The buried interface between self-assembled monolayers (SAMs) and perovskite absorbers critically governs charge extraction and stability in inverted perovskite solar cells, yet remains structurally mismatched and poorly controlled. Here, we report a buried-interface engineering strategy inspired by non‑covalent molecular templating, enabled by complementary triphenylamine-based molecular building blocks. A triphenylamine-based ammonium salt, 2-(4-(diphenylamino)phenyl)ethanammonium iodide (TPANI), is introduced into the perovskite precursor, while a structurally matched triphenylamine-based bisphosphonic acid SAM deposited on ITO serves as the hole-selective layer. Non-covalent interactions at the buried interface induce molecular templating and interfacial organization of TPANI, strengthening SAM/perovskite adhesion and reducing intergranular groove depth at the buried side of the perovskite film. The resulting monolithically integrated interface suppresses buried interfacial defects, improves energy-level alignment, and facilitates hole extraction. Consequently, inverted devices achieve a power conversion efficiency of 26.58% with an exceptionally high fill factor of 86.72%, together with markedly enhanced operational stability. These results demonstrate that non‑covalent molecular templating provides an effective and general strategy for engineering buried interfaces in perovskite photovoltaics.

Atomic layer deposition (ALD) of tin oxide (SnOx) is widely used as a barrier layer in perovskite solar cells (PSCs). However, it suffers from interfacial delamination and non-conformal growth on organic electron transport layers (ETLs). To address this, we developed an amphiphilic molecular binder, N,N′-diethanolamino (propyl) perylene diimide (PDI-4OH), as a templating layer at the ETL/ALD SnOx interface. Its π-conjugated core enhances adhesion with ETLs, while its hydroxyl groups promote covalent Sn–O bonding during ALD cycles, forming an atomically interlocked interface. The resulting SnOx exhibits optimal composition and morphology, improving electron extraction and barrier properties. This enables 1.55 eV inverted PSCs to achieve a champion efficiency of 27.08% (certified 26.59%), with wide-band-gap (1.80 and 1.85 eV) devices reaching 19.92% and 18.82%, respectively. The 1.55-eV devices retain ∼98% of initial efficiency after 1,200 h at 85°C under maximum power point (MPP) tracking (ISOS-L-2I) and show excellent durability under thermal cycling and damp heat tests.

Self-assembled monolayers (SAMs) have emerged as an effective interfacial strategy for improving charge extraction and interfacial energetics in organic solar cells (OSCs); however, limited operational stability, particularly under prolonged high-temperature conditions, remains a critical challenge for practical deployment. Here, we systematically engineer SAM terminal groups to elucidate how interfacial molecular interactions between the SAM and the bulk-heterojunction active layer govern device efficiency and thermal stability. Expanding the aromatic ring size of the SAM pendant groups enhances π-π and van der Waals interactions, leading to stronger molecular coupling and a more intact and robust interfacial structure at both the electrode/SAM and SAM/active-layer interfaces. In particular, SAMs incorporating naphthalene pendant groups exhibit significantly strengthened intermolecular interactions, effectively suppressing thermally induced morphological degradation under elevated temperatures. As a result, PM6:BTP-eC9-based binary and ternary organic solar cells achieve power conversion efficiencies of 19.73% and 20.15%, respectively. Notably, devices employing this interfacial molecular locking strategy deliver a T90 operational lifetime of 150 h under maximum power point tracking at 85°C, representing an order-of-magnitude improvement compared to SAMs without pendant groups. These findings establish aromatic terminal group expansion as an effective molecular design strategy for simultaneously enhancing efficiency and thermal stability in organic solar cells.

Efficient and stable wide-band-gap (WBG) perovskites are pivotal for advancing tandem photovoltaic efficiency beyond the thermodynamic limits of single-junction cells. However, the development of these materials, particularly in multi-cation (e.g., formamidinium [FA]/methylammonium [MA]/cesium [Cs]) mixed-halide compositions, is severely hampered by light-induced phase segregation and large open-circuit voltage deficits. This instability originates from compositional heterogeneity established during film crystallization, leading to localized band-gap variations and detrimental carrier recombination pathways. Here, we report a molecular-complex doping strategy that achieves spatially homogeneous elemental distribution in 1.78 eV FA0.8MA0.1Cs0.1(I0.6Br0.4)3 perovskite films. Consequently, we fabricate a WBG perovskite solar cell that delivers a Voc exceeding 1.38 V (surpassing 90% of its thermodynamic limit) and a power conversion efficiency of over 20.5%, with a fill factor above 83%. Integrating this optimized subcell with a narrow-band-gap perovskite, we demonstrate a monolithic all-perovskite tandem solar cell achieving a power conversion efficiency of 30.4% (certified at 29.7%).

Non-geminate recombination in organic photovoltaics (OPVs) forms low-energy spin-triplet excitons (T1) that are known to result in irreversible, non-radiative relaxations1-5. Here we experimentally show in an OPV system incorporating a non-fullerene acceptor with a narrowed singlet-triplet gap that T1 excitons can be redissociated through the interfacial charge-transfer state to form free carriers. We corroborate this by identifying the increased population of free carriers following triplet sensitization of the acceptor in an OPV blend, and illustrate the way in which this mechanism alters the evolution of T1 and free carrier populations. We reveal how the distribution of orbitals in the molecule and exciton delocalization in aggregates affect the singlet-triplet energetics of the acceptor in the condensed phase, rendering the traffic between T1 and the spin-triplet charge-transfer state controllable. By introducing this acceptor as a ternary component into other host OPV systems, we manage to recover the triplet-mediated losses and improve OPV efficiencies by maximizing the number of extractable photocarriers. This study deepens our understanding of the fundamentals of OPVs, and shows how to develop future organic optoelectronics by demonstratating the recovery of low-energy T1 excitons into usable charges for electricity or light generation instead of heat.

Light-emitting colloidal lead halide perovskite nanocrystals (PeNCs) are considered promising candidates for next-generation vivid displays. However, the operational stability of light-emitting diodes (LEDs) based on PeNCs is still lower than those based on polycrystalline perovskite films, which requires an understanding of defect formation in PeNCs, both inside the crystal lattice ("bulk") and at the surface. Meanwhile, uncontrollable ion redistribution and electrochemical reactions under LED operation can be severe, which is also related to the bulk and surface quality of PeNCs, and a well-designed device architecture can boost carrier injection and balance radiative recombination. In this review, we consider bulk and surface reconstruction of PeNCs by enhancing the crystal lattice rigidity and rationally selecting the surface ligands. Degradation pathways of PeNCs under applied voltage are discussed, and strategies are considered to avoid both undesirable ion migration and electrochemical reactions in the PeNC films. Subsequently, other critical issues hindering the commercial application of PeNC LEDs are discussed, including the toxicity of Pb in lead halide perovskites, scale-up deposition of PeNC films, and design of active-matrix prototypes for high-resolution LED modules.