Unraveling the Solution Aggregation Structures and Processing Resiliency of High-Efficiency Organic Photovoltaic Blends.

The solution aggregation structure of conjugated polymers is crucial to the morphology and resultant optoelectronic properties of organic electronics and is of considerable interest in the field. Precise characterizations of the solution aggregation structures of organic photovoltaic (OPV) blends and their temperature-dependent variations remain challenging. In this work, the temperature-dependent solution aggregation structures of three representative high-efficiency OPV blends using small-angle X-ray/neutron scattering are systematically probed. Three cases of solution processing resiliency are elucidated in state-of-the-art OPV blends. The exceptional processing resiliency of high-efficiency PBQx-TF blends can be attributed to the minimal changes in the multiscale solution aggregation structure at elevated temperatures. Importantly, a new parameter, the percentage of acceptors distributed within polymer aggregates (Ф), for the first time in OPV blend solution, establishes a direct correlation between Ф and performance is quantified. The device performance is well correlated with the Kuhn length of the cylinder related to polymer aggregates L1 at the small scale and the Ф at the large scale. Optimal device performance is achieved with L1 at ≈30 nm and Ф within the range of 60 ± 5%. This study represents a significant advancement in the aggregation structure research of organic electronics.

Dye-Containing Polymers with π-Extened Diketopyrropyrrole Derivatives for Semi-transparent Organic Photovoltaics.

Dye-containing polymers P1 (PEDPP-OT-BDT) and P2 (PEDPP-OT-BDTT) including a π-extended diketopyropyrrole (DPP) derivative and electron-rich thiophene fused ring units (4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene for P1 and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene for P2) were synthesized as narrow band gap dyes. A π-extended DPP (EDPP-OT-BrPh), fragment of the polymers P1 and P2, was obtained by extending the π-conjugation of DPP using Ru(III)-catalyzed C-H and N-H activation reported by Gonka et al. in 2019, exhibiting a high quantum yield (φem = 0.84) and small HOMO-LUMO gap (Eg = 1.69 eV) due to the spatial overlap of the HOMO and LUMO orbitals. The solubility of the π-extended DPP was improved by introducing four 2-octylthophene side chains around the periphery of the planer dye moiety, while maintaining the high planarity of the dye molecule, which is essential to the function of optoelectronic devices. As a result, P1 and P2, polymerized with the π-extended DPP and BDT derivatives, exhibit carrier mobility of approximately 10-5 cm2/Vs in organic field-effect transistors (OFETs). In bulk heterojunction (BHJ) solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), they demonstrate a power conversion efficiency (PCE) of 1.0% with an average transmittance (AVTs) of around 60%.

The Multi-Functional Third Acceptor Realizes the Synergistic Improvement in Photovoltaic Parameters and the High-Ratio Tolerance of Ternary Organic Photovoltaics.

The ternary strategy proves effective for breakthroughs in organic photovoltaics (OPVs). Elevating three photovoltaic parameters synergistically, especially the proportion-insensitive third component, is crucial for efficient ternary devices. This work introduces a molecular design strategy by comprehensively analyzing asymmetric end groups, side-chain engineering, and halogenation to explore the outstanding optoelectronic properties of the proportion-insensitive third component in efficient ternary systems. Three asymmetric non-fullerene acceptors (BTP-SA1, BTP-SA2, and BTP-SA3) are synthesized based on the Y6 framework and incorporated as the third component into the D18:Y6 binary system. BTP-SA3, featuring asymmetric terminal (difluoro-indone and dichloride-cyanoindone terminal), with branched alkyl side chains, exhibited high open-circuit voltage (VOC), balanced crystallinity and compatibility, achieving synergistic enhancements in VOC (0.862 V), short circuit-current density (JSC, 27.52 mA cm-2), fill fact (FF, 81.01%), and power convert efficiency (PCE, 19.19%). Device based on D18/Y6:BTP-SA3 (layer-by-layer processed) reached a high efficiency of 19.36%, demonstrating a high tolerance for BTP-SA3 (10-50%). This work provides novel insights into optimizing OPVs performances in multi-component systems and designing components with enhanced tolerance.

High-Performance Intrinsically Stretchable Organic Photovoltaics Enabled by Robust Silver Nanowires/S-PH1000 Hybrid Transparent Electrodes.

Intrinsically stretchable organic photovoltaics (is-OPVs) hold significant promise for integration into self-powered wearable electronics. However, their potential is hindered by the lack of sufficient consistency between optoelectronic and mechanical properties. This is primarily due to the limited availability of stretchable transparent electrodes (STEs) that possess both high conductivity and stretchability. Here, a hybrid STE with exceptional conductivity, stretchability, and thermal stability is presented. Specifically, STEs are composed of the modified PH1000 (referred to as S-PH1000) and silver nanowires (AgNWs). The S-PH1000 endows the STE with good stretchability and smoothens the surface, while the AgNWs enhance the charge transport. The resulting hybrid STEs enable is-OPVs to a remarkable power conversion efficiency (PCE) of 16.32%, positioning them among the top-performing is-OPVs. With 10% elastomer, the devices retain 82% of the initial PCE after 500 cycles at 20% strain. Additionally, OPVs equipped with these STEs exhibit superior thermal stability compared to those using indium tin oxide electrodes, maintaining 75% of the initial PCE after annealing at 85 °C for 390 h. The findings underscore the suitability of the designed hybrid electrodes for efficient and stable is-OPVs, offering a promising avenue for the future application of OPVs.

Design, Synthesis, and Theoretical Studies on the Benzoxadiazole and Thienopyrrole Containing Conjugated Random Copolymers for Organic Solar Cell Applications.

In this study, six different donor-π-acceptor1-π-donor-acceptor2 type random co-polymers containing benzodithiophene as a donor, benzooxadiazole (BO), and thieno[3,4-c]pyrrole-4,6-dione (TPD) as acceptor, have been synthesized and characterized. In addition to the acceptor core ratio at different values, the effect of aromatic bridge structures on the optical, electronic, and photovoltaic properties of six different random co-polymers is investigated by using thiophene and selenophene structures as aromatic bridge units. To investigate how the acceptor unit ratio and replacement of aromatic bridge units impact the structural, electronic, and optical properties of the polymers, density functional theory (DFT) calculations are carried out for the tetramer models. The open-circuit voltage (VOC), which is strongly correlated with the HOMO levels of the donor material, is enhanced with the increasing ratio of the TPD moiety. On the other hand, the short-circuit current (JSC), which is associated with the absorption ability of the donor material, is improved by the increasing ratio of BO moiety with the π-bridges. BO moiety dominant selenophene π-bridged co-polymer (P4) showed the best performance with a power conversion efficiency (PCE) of 6.26%, a JSC of 11.44 mA cm2, a VOC of 0.80 V, and a fill factor (FF) of 68.81%.

Achieving High Efficiency and Stability in Organic Photovoltaics with a Nanometer-Scale Twin p-i-n Structured Active Layer.

In pursuing high stability and power conversion efficiency for organic photovoltaics (OPVs), a sequential deposition (SD) approach to fabricate active layers with p-i-n structures (where p, i, and n represent the electron donor, mixed donor:acceptor, and electron acceptor regions, respectively, distinctively different from the bulk heterojunction (BHJ) structure) has emerged. Here, we present a novel approach that by incorporating two polymer donors, PBDBT-DTBT and PTQ-2F, and one small-molecule acceptor, BTP-3-EH-4Cl, into the active layer with sequential deposition, we formed a device with nanometer-scale twin p-i-n structured active layer. The twin p-i-n PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl device involved first depositing a PBDBT-DTBT:PTQ-2F blend under layer and then a BTP-3-EH-4Cl top layer and exhibited an improved power conversion efficiency (PCE) value of 18.6%, as compared to the 16.4% for the control BHJ PBDBT-DTBT:PTQ-2F:BTP-3-EH-4Cl device or 16.6% for the single p-i-n PBDBT-DTBT/BTP-3-EH-4Cl device. The PCE enhancement resulted mainly from the twin p-i-n active layer's multiple nanoscale charge carrier pathways that contributed to an improved fill factor and faster photocurrent generation based on transient absorption studies. The PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl film possessed a vertical twin p-i-n morphology that was revealed through secondary ion mass spectrometry and synchrotron grazing-incidence small-angle X-ray scattering analyses. The thermal stability (T80) at 85 °C of the twin p-i-n PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl device surpassed that of the single p-i-n PBDBT-DTBT/BTP-3-EH-4Cl devices (906 vs 196 h). This approach of providing a twin p-i-n structure in the active layer can lead to substantial enhancements in both the PCE and stability of organic photovoltaics, laying a solid foundation for future commercialization of the organic photovoltaics technology.

Over 19% Efficient Inverted Organic Photovoltaics Featuring a Molecularly Doped Metal Oxide Electron-Transporting Layer.

Molecular doping is commonly utilized to tune the charge transport properties of organic semiconductors. However, applying this technique to electrically dope inorganic materials like metal oxide semiconductors is challenging due to the limited availability of molecules with suitable energy levels and processing characteristics. Herein, n-type doping of zinc oxide (ZnO) films is demonstrated using 1,3-dimethylimidazolium-2-carboxylate (CO2-DMI), a thermally activated organic n-type dopant. Adding CO2-DMI into the ZnO precursor solution and processing it atop a predeposited indium oxide (InOx) layer yield InOx/n-ZnO heterojunctions with increased electron field-effect mobility of 32.6 cm2 V-1 s-1 compared to 18.5 cm2 V-1 s-1 for the pristine InOx/ZnO bilayer. The improved electron transport originates from the ZnO's enhanced crystallinity, reduced hydroxyl concentrations, and fewer oxygen vacancy groups upon doping. Applying the optimally doped InOx/n-ZnO heterojunctions as the electron-transporting layers (ETLs) in organic photovoltaics (OPVs) yields cells with improved power conversion efficiency of 19.06%, up from 18.3% for devices with pristine ZnO, and 18.2% for devices featuring the undoped InOx/ZnO ETL. It is shown that the all-around improved OPV performance originates from synergistic effects associated with CO2-DMI doping of the thermally grown ZnO, highlighting its potential as an electronic dopant for ZnO and potentially other metal oxides.

Printing and Coating Techniques for Scalable Organic Photovoltaic Fabrication.

Within recent years, there has been an increased interest towards organic photovoltaics (OPVs), especially with their significant device performance reaching beyond 19% since 2022. With these advances in the device performance of laboratory-scaled OPVs, there has also been more attention directed towards using printing and coating methods that are compatible with large-scale fabrication. Though large-area (>100 cm2) OPVs have reached an efficiency of 15%, this is still behind that of laboratory-scale OPVs. There also needs to be more focus on determining strategies for improving the lifetime of OPVs that are suitable for scalable manufacturing, as well as methods for reducing material and manufacturing costs. In this paper, we compare several printing and coating methods that are employed to fabricate OPVs, with the main focus towards the deposition of the active layer. This includes a comparison of performances at laboratory (<1 cm2), small (1-10 cm2), medium (10-100 cm2), and large (>100 cm2) active area fabrications, encompassing devices that use scalable printing and coating methods for only the active layer, as well as "fully printed/coated" devices. The article also compares the research focus of each of the printing and coating techniques and predicts the general direction that scalable and large-scale OPVs will head towards.

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells.

Evaporable indano[60]fullerene ketone (FIDO) was converted to indano[60]fullerene thioketone (FIDS) in high yield by using Lawesson's reagent. Three compounds with different substituents in para position were successfully converted to the corresponding thioketones, showing that the reaction tolerates compounds with electron-donating and electron-withdrawing substituents. Computational studies with density functional theory revealed the unique vibrations of the thioketone group in FIDS. The molecular structure of FIDS was confirmed by single-crystal X-ray analysis. Bulk heterojunction organic solar cells using three evaporable fullerene derivatives (FIDO, FIDS, C60) as electron-acceptors were compared, and the open-circuit voltage with FIDS was 0.16 V higher than that with C60.

Polymer Fiber Rigid Network with High Glass Transition Temperature Reinforces Stability of Organic Photovoltaics.

Organic photovoltaics (OPVs) need to overcome limitations such as insufficient thermal stability to be commercialized. The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology, however, exhibiting limited applicability. Therefore, it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor-acceptor compatibilizers, or by introducing another third component. Herein, a unique approach is presented, based on constructing a polymer fiber rigid network with a high glass transition temperature (Tg) to impede the movement of acceptor and donor molecules, to immobilize the active layer morphology, and thereby to improve thermal stability. A high-Tg one-dimensional aramid nanofiber (ANF) is utilized for network construction. Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart. The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart, thereby leaving fundamental processes such as charge separation, transport, and collection, determining the device efficiency, largely unaltered. This strategy is also successfully applied to other photovoltaic systems. The strategy of incorporating a polymer fiber rigid network with high Tg offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.

Electron Transfer Enhanced by a Minimal Energetic Driving Force at the Organic-Semiconductor Interface.

The energetic driving force for electron transfer must be minimized to realize efficient optoelectronic devices including organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). Exploring the dynamics of a charge-transfer (CT) state at an interface leads to a comprehension of the relationship between energetics, electron-transfer efficiency, and device performance. Here, we investigate the electron transfer from the CT state to the triplet excited state (T1) in upconversion OLEDs with 45 material combinations. By analyzing the CT emission and the singlet excited-state emission from triplet-triplet annihilation via the dark T1, their energetics and electron-transfer efficiencies are extracted. We demonstrate that the CT→T1 electron transfer is enhanced by the stronger CT interaction and a minimal energetic driving force (<0.1 eV), which is explained using the Marcus theory with a small reorganization energy of <0.1 eV. Through our analysis, a novel donor-acceptor combination for the OLED is developed and shows an efficient blue emission with an extremely low turn-on voltage of 1.57 V. This work provides a solution to control interfacial CT states for efficient optoelectronic devices without energy loss.

Enhancement of the internal quantum efficiency in strongly coupled P3HT-C60 organic photovoltaic cells using Fabry-Perot cavities with varied cavity confinement.

The short exciton diffusion length in organic semiconductors results in a strong dependence of the conversion efficiency of organic photovoltaic (OPV) cells on the morphology of the donor-acceptor bulk-heterojunction blend. Strong light-matter coupling provides a way to circumvent this dependence by combining the favorable properties of light and matter via the formation of hybrid exciton-polaritons. By strongly coupling excitons in P3HT-C60 OPV cells to Fabry-Perot optical cavity modes, exciton-polaritons are formed with increased propagation lengths. We exploit these exciton-polaritons to enhance the internal quantum efficiency of the cells, determined from the external quantum efficiency and the absorptance. Additionally, we find a consistent decrease in the Urbach energy for the strongly coupled cells, which indicates the reduction of energetic disorder due to the delocalization of exciton-polaritons in the optical cavity.

Near-Infrared Absorbing Aza-BODIPY Dyes for Optoelectronic Applications.

Organic dyes that absorb light in the visible to near-infrared region have garnered significant interest, owing to their extensive utility in organic photovoltaics and various biomedical applications. Aza-boron-dipyrromethene (Aza-BODIPY) dyes are a class of chromophores with impressive photophysical properties such as tunable absorption from the visible region towards near infrared (NIR) region, high molar absorptivity, and fluorescence quantum yield. In this review, we discuss the developments in the aza-BODIPYs, related to their synthetic routes, photophysical properties and their applications. Their design strategies, modifications in chemical structures, mode/position of attachment, and their impact on photo-physical properties are reviewed. The potential applications of aza-BODIPY derivatives such as organic solar cells, photodynamic therapy, boron-neutron capture therapy, fluorescence sensors, photo-redox catalysis, photoacoustic probes and optoelectronic devices are explained.

Eliminating the Burn-in Loss of Efficiency in Organic Solar Cells by Applying Dimer Acceptors as Supramolecular Stabilizers.

The meta-stable active layer morphology of organic solar cells (OSCs) is identified as the main cause of the rapid burn-in loss of power conversion efficiency (PCE) during long-term device operation. However, effective strategies to eliminate the associated loss mechanisms from the initial stage of device operation are still lacking, especially for high-efficiency material systems. Herein, the introduction of molecularly engineered dimer acceptors with adjustable thermal transition properties into the active layer of OSCs to serve as supramolecular stabilizers for regulating the thermal transitions and optimizing the crystallization of the absorber composites is reported. By establishing intimate π-π interactions with small-molecule acceptors, these stabilizers can effectively reduce the trap-state density (Nt) in the devices to achieve excellent PCEs over 19%. More importantly, the low Nt associated with an initially optimized morphology can be maintained under external stresses to significantly reduce the PCE burn-in loss in devices. This research reveals a judicious approach to improving OPV stability by establishing a comprehensive correlation between material properties, active-layer morphology, and device performance, for developing burn-in-free OSCs.

The Nanoscale Structure and Stability of Organic Photovoltaic Blends Processed with Solvent Additives.

Controlling the nanomorphology in bulk heterojunction photoactive blends is crucial for optimizing the performance and stability of organic photovoltaic (OPV) technologies. A promising approach is to alter the drying dynamics and consequently, the nanostructure of the blend film using solvent additives such as 1,8-diiodooctane (DIO). Although this approach is demonstrated extensively for OPV systems incorporating fullerene-based acceptors, it is unclear how solvent additive processing influences the morphology and stability of nonfullerene acceptor (NFA) systems. Here, small angle neutron scattering (SANS) is used to probe the nanomorphology of two model OPV systems processed with DIO: a fullerene-based system (PBDB-T:PC71BM) and an NFA-based system (PBDB-T:ITIC). To overcome the low intrinsic neutron scattering length density contrast in polymer:NFA blend films, the synthesis of a deuterated NFA analog (ITIC-d52) is reported. Using SANS, new insights into the nanoscale evolution of fullerene and NFA-based systems are provided by characterizing films immediately after fabrication, after thermal annealing, and after aging for 1 year. It is found that DIO processing influences fullerene and NFA-based systems differently with NFA-based systems characterized by more phase-separated domains. After long-term aging, SANS reveals both systems demonstrate some level of thermodynamic induced domain coarsening.

Spray-Coated MoO3 Hole Transport Layer for Inverted Organic Photovoltaics.

This study focuses on the hole transport layer of molybdenum trioxide (MoO3) for inverted bulk heterojunction (BHJ) organic photovoltaics (OPVs), which were fabricated using a combination of a spray coating and low-temperature annealing process as an alternative to the thermal evaporation process. To achieve a good coating quality of the sprayed film, the solvent used for solution-processed MoO3 (S-MoO3) should be well prepared. Isopropanol (IPA) is added to the as-prepared S-MoO3 solution to control its concentration. MoO3 solutions at concentrations of 5 mg/mL and 1 mg/mL were used for the spray coating process. The power conversion efficiency (PCE) depends on the concentration of the MoO3 solution and the spray coating process parameters of the MoO3 film, such as flow flux, spray cycles, and film thickness. The results of devices fabricated from solution-processed MoO3 with various spray fluxes show a lower PCE than that based on thermally evaporated MoO3 (T-MoO3) due to a limiting FF, which gradually increases with decreasing spray cycles. The highest PCE of 2.8% can be achieved with a 1 mg/mL concentration of MoO3 solution at the sprayed flux of 0.2 mL/min sprayed for one cycle. Additionally, S-MoO3 demonstrates excellent stability. Even without any encapsulation, OPVs can retain 90% of their initial PCE after 1300 h in a nitrogen-filled glove box and under ambient air conditions. The stability of OPVs without any encapsulation still has 90% of its initial PCE after 1300 h in a nitrogen-filled glove box and under air conditions. The results represent an evaluation of the feasibility of solution-processed HTL, which could be employed for a large-area mass production method.

CPE-Na-Based Hole Transport Layers for Improving the Stability in Nonfullerene Organic Solar Cells: A Comprehensive Study.

Organic photovoltaic (OPV) cells have experienced significant development in the last decades after the introduction of nonfullerene acceptor molecules with top power conversion efficiencies reported over 19% and considerable versatility, for example, with application in transparent/semitransparent and flexible photovoltaics. Yet, the optimization of the operational stability continues to be a challenge. This study presents a comprehensive investigation of the use of a conjugated polyelectrolyte polymer (CPE-Na) as a hole layer (HTL) to improve the performance and longevity of OPV cells. Two different fabrication approaches were adopted: integrating CPE-Na with PEDOT:PSS to create a composite HTL and using CPE-Na as a stand-alone bilayer deposited beneath PEDOT:PSS on the ITO substrate. These configurations were compared against a reference device employing PEDOT:PSS alone, as the HTL increased efficiency and fill factor. The instruments with CPE-Na also demonstrated increased stability in the dark and under simulated operational conditions. Device-based PEDOT:PSS as an HTL reached T80 after 2500 h while involving CPE-Na in the device kept at T90 in the same period, evidenced by a reduced degradation rate. Furthermore, the impedance spectroscopy and photoinduced transient methods suggest optimized charge transfer and reduced charge carrier recombination. These findings collectively highlight the potential of CPE-Na as a HTL optimizer material for nonfluorine OPV cells.

Achieving High Fill Factor in Organic Photovoltaic Cells by Tuning Molecular Electrostatic Potential Fluctuation.

In the field of organic photovoltaics (OPVs), significant progress has been made in tailoring molecular structures to enhance the open-circuit voltage and the short-circuit current density. However, there remains a crucial gap in the development of coordinated material design strategies focused on improving the fill factor (FF). Here, we introduce a molecular design strategy that incorporates electrostatic potential fluctuation to design organic photovoltaic materials. By reducing the fluctuation amplitude of IT-4F, we synthesized a new acceptor named ITOC6-4F. When using PBQx-TF as a donor, the ITOC6-4F-based cell shows a markedly low recombination rate constant of 0.66×10-14 cm3 s-1 and demonstrates an outstanding FF of 0.816, both of which are new records for binary OPV cells. Also, we find that a small fluctuation amplitude could decrease the energetic disorder of OPV cells, reducing energy loss. Finally, the ITOC6-4F-based cell creates the highest efficiency of 16.0 % among medium-gap OPV cells. Our work holds a vital implication for guiding the design of high-performance OPV materials.

Charge Transfer Dynamics in Organic-Inorganic Hybrid Heterostructures-Insights by Vibrational-Sum Frequency Generation Spectroscopy.

Organic-inorganic heterostructures play a pivotal role in modern electronic and optoelectronic applications including photodetectors and field effect transistors, as well as in solar energy conversion such as photoelectrodes of dye-sensitized solar cells, photoelectrochemical cells, and in organic photovoltaics. To a large extent, performance of such devices is controlled by charge transfer dynamics at and across (inner) interfaces, e.g., between a wide band gap semiconductor and molecular sensitizers and/or catalysts. Hence, a detailed understanding of the structure-dynamics-function relationship of such functional interfaces is necessary to rationalize possible performance limitations of these materials and devices on a molecular level. Vibrational sum-frequency generation (VSFG) spectroscopy, as an interface-sensitive spectroscopic technique, allows to obtain chemically specific information from interfaces and combines such chemical insights with ultrafast time resolution, when integrated as a spectroscopic probe into a pump-probe scheme. Thus, this minireview discusses the advantages and potential of VSFG spectroscopy for investigating interfacial charge transfer dynamics and structural changes at inner interfaces. A critical perspective of the unique spectroscopic view of otherwise inaccessible interfaces is presented, which we hope opens new opportunities for an improved understanding of function-determining processes in complex materials, and brings together communities who are devoted to designing materials and devices with spectroscopists.

Unveiling the Impact of Light-Induced Acceptor-Generated ROS on Device Stability in Organic Photovoltaics.

The intrinsic stability of the acceptor is a crucial component of the photovoltaic device stability. In this study, we investigated the efficiency and stability of the nonfused-ring acceptors LC8 and BC8 under indoor light conditions. Interestingly, we found that devices based on BC8 with terminal side chains exhibited a higher indoor efficiency and stability. Through accelerated aging experiments, we discovered that the acceptors generate singlet oxygen under light exposure with BC8 demonstrating lower levels of ROS compared to LC8. We attribute this difference to the modulation of the acceptor aggregation orientation. Furthermore, the generated reactive oxygen species (ROS) further deteriorate the acceptor structure, and this phenomenon is also observed in high-efficiency acceptor structures, such as Y6. Our research reveals important mechanisms of acceptor photo-oxidation processes, providing a theoretical basis for enhancing the intrinsic stability of acceptors.