Higher Jsc Research Articles

Numerical simulation of the effect of gradual substitution of sulfur with selenium or tin with germanium in Cu2ZnSnS4 absorber layer on kesterite solar cell efficiency

To enhance the efficiency of kesterite Cu2ZnSnS4 solar cell, different gradient strategies are investigated. Absorber layer gradient is obtained by partial substitution of sulfur with selenium or tin with germanium. The PV Parameters are calculated using the SCAPS1D program. The effect of the front, back, and double gradient on the cell parameters was investigated. We proposed also the fully graded gap absorber layer profile. The opencircuit voltage has increased to 1.040V, the fill factor has increased to 71.69%, and the efficiency has exceeded 22.95%. In contrast to other types of gradients, the short-circuit current density remains high (Jsc= 39.7mA / cm2 ).

Alkyl Branching Sites on π-Spacers for Dipyran-Based High-Efficiency Organic Solar Cells

The configuration of A-π-D-π-A type is one effective way for nonfullerene acceptor (NFA) design to achieve excellent photovoltaic performance with reduced synthetic complexity. Additional side chain engineering either around the center or at the terminus of the D core has been widely adopted in the molecular optimization of A-D-A type NFAs. Herein, the branch alkyl and branched sites of the side chains on π-spacers of A-π-D-π-A type acceptors are carefully evaluated, where dipyran ladder-type core Ph-DTDPi is employed as the D core. All three dipyran-based acceptors have been fully characterized and distinct behaviors have been detected in solid UV–vis absorption spectra, molecular stacking orientation, and miscibility with the polymer donor accompany with the side chain alternation. The balanced crystallization characteristics and good miscibility endows the blend film of DTDPi-C2:PBDB-T with a uniform morphology containing even smaller nanoscopic structures with interweaved fibers and balls, which enlarges the donor–acceptor contact and facilitates efficient exciton diffusion and separation. Hence, Ph-DTDPi-C2-based devices achieved a high PCE of 12.4% with a high JSC of 21.88 mA/cm2 and significantly enhanced FF of 69.26%. In short, adjusting the alkyl branch point on the π bridge is an effective strategy for dipyran-based acceptor and future molecular design.

Photovoltaic performance optimization of integrated perovskite/organic solar cells based on PM6:Y6 polymer non-fullerene system

Integrated perovskite/organic solar cells (IPOSCs) based on CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/PM6:Y6(BTP-4F) are successfully prepared through process innovation and thin film optimization technology. The quality of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/PM6:Y6 mixed films is greatly optimized, and the interlayer ohmic contact is obtained by regulating the additive DIO and annealing treatment. At the same time, the mobility of holes and electrons in the organic layer in the near infrared region are, respectively, 8.3×10<sup>–3</sup> cm<sup>2</sup>/(V·s) and 8.8×10<sup>–3</sup> cm<sup>2</sup>/(V·s), which can match the mobility of holes and electrons in the visible perovskite layer, achieving the carrier transport balance in the microscopic pathway. The device has high short-circuit current density <i>J</i><sub>sc</sub> and high filling factor FF. In addition, by optimizing the mass ratio of polymer non-fullerene system PM6:Y6 to form a film, the density of non-radiation recombination sites and carrier recombination in the film are significantly reduced, making the extraction and transport of electrons and holes more efficient, and providing greater driving force to improve carrier transport. At the same time, a wider depletion region is formed to inhibit carrier recombination and increase the open-circuit voltage <i>V</i><sub>oc</sub>. The short-circuit current density of the optimized integrated solar cell increases to 25.88 A/cm<sup>2</sup>, the open-circuit voltage <i>V</i><sub>oc</sub> increases to 1.18 V, the filling factor FF reaches 80%, the optical response expands to 950 nm, the external quantum efficiency reaches 90% in the visible region, and the optimal energy conversion efficiency is as high as 24.42%. This is one of the highest efficiencies reported in IPOSCs. The results show that it is an effective method to enhance the near-infrared light absorption of perovskite solar cells and improve the performance of IPOSCs by combining the materials in visible region and the polymer non-fullerene system in near infrared region and optimizing the device structure. It lays a theoretical foundation for developing high efficiency IPOSCs in the future.

Challenging PM6-like donor polymers for pairing with a Y-type state-of-the-art acceptor in binary blends for bulk heterojunction solar cells.

Being fluorine-free and a high performance material as a small organic acceptor molecule, BTP-eC9 has been well mixed with BDT-based PM6 donor polymers for providing satisfactory photovoltaic properties, especially towards future large scale/large area solar cell production. However, as one of the key electrical outputs from such binary active layer materials, the open circuit voltage (VOC) was limited to ca. 0.84 V, which needs to be further improved for BTP-eC9 to have a bright future. This paper focuses on the molecular design of alkylthio- and alkoxy-phenyl flanked benzo[1,2-b:4,5-b']dithiophene-based conjugated polymers (PBDT-PS-ttTPD or P10 for short and PBDT-PO-ttTPD or P11), which were successfully synthesized and applied as donor materials for pairing with BTP-eC9 in organic photovoltaic (OPV) devices. By fine-tuning the side chains of the benzodithiophene (BDT) moiety, such non-fullerene OPV devices with normal configuration demonstrate an attractively high open circuit voltage (VOC) of 0.89 and 0.87 V in P10/BTP-eC9 and P11/BTP-eC9 based binary single bulk heterojunction OPV devices, while still maintaining an excellent JSC of 22.7 and 20.0 mA cm-2 with a final power conversion efficiency (PCE) of 12.93% and 9.37%, respectively. The alkylthio-phenyl chain substituted BDT polymer exhibits better photovoltaic performance in all aspects than the alternative with alkoxy chains due to the synergistic effect of the alkylthio-phenyl flanked BDT, TPD, and π-bridge (thieno[3,2-b]thiophene).

Crystallization and Defect Chemistry Dual Engineering for MAPbI3 Perovskite Solar Cells with Efficiency Approaching 22%

Methylammonium lead triiodide (MAPI) has been the most commonly used light absorber layer for perovskite solar cells and also shows potentially high theoretical efficiency. However, the achievable efficiencies so far still lag behind those of their formamidinium- or mixed cation-based counterparts. In this work, the dual additives 2-mercaptopyridine (2-MP) and 1,2-dichlorobenzene (DCB) are applied to regulate the crystal orientation, yielding a high-crystal quality MAPI film and passivating the trap states of the film. Encouragingly, we are able to distinguish the efficacy of the two additives. DCB effectively reduced the size of colloidal clusters in the perovskite precursor, thus helping the wet film reach the critical concentration to initialize rapid nucleation. The resulting MAPI film exhibited extended grain size with a stronger grain orientation and smoother surface. With the subsequent introduction of 2-MP, the high crystal quality was maintained, and 2-MP interacted with uncoordinated Pb defects and passivated the related traps. The dual additive-processed devices exhibited the champion efficiency of 21.83% with a simultaneously high Jsc of 24.01 mA/cm2 and Voc of 1.15 V. This work provides a means to engineer the crystallization quality and defect chemistry toward efficient MAPbI3 perovskite solar cells.

Straddling type sandwiched absorber based solar cell structure

We have proposed a solar cell structure that could utilize sub-bandgap photons along with the usual above bandgap energy photons. This device configuration could achieve efficiency beyond the single bandgap solar cell limit of 33 %. A low bandgap intrinsic absorber is embedded into a high bandgap intrinsic absorber making a straddling type sandwiched configuration. Stradling type alignment and conduction band offset make a confinement region in the sandwich absorber region. This configuration is put into a p+ and n+ for providing an internal electric field. The various aspect of confinement region carrier transport, and its physical parameters controlling device performance such as thickness, position, and barrier height, are investigated. The device working in terms of recombination and net power generation is optimized. The optimal efficiency of such a structure is observed to be 43 % with high VOC and JSC values.

Eco-friendly direct-current pulsed electropolymerization of polyaniline nanofibers on synthetic graphite substrate for counter electrode in dye-sensitized solar cells

ABSTRACT This paper reports the study of the effect of varying duty cycles on the synthesis of PANI by pulsed electropolymerization method to the performance of PANI as a counter electrode in DSSC. The deposited PANI is in emeraldine salt form, confirmed by FTIR-ATR and Raman spectroscopy. SEM analysis observed that all PANIs has nanofiber morphology. PANI with a 10% duty cycle provides the smallest average diameters and lowest film thickness (11.56 μm), lowest RCT (59.00 Ω), lowest RS (40.06 Ω), highest VOC (0.688 V), and highest JSC (9.066 mA cm−2) that lead to the highest performance (η = 2.402%).

Electron transport of chemically treated graphene quantum dots-based dye-sensitized solar cells

The main aim of this work is to elucidate the effect of the chemical treatment of titanium tetrachloride (TiCl4) in graphene quantum dots (GQDs)-based dye-sensitized solar cells (DSSCs). Although this type of chemical treatment has been used in DSSCs, the detailed electron transport properties of TiCl4-treated TiO2/GQDs+dye have not been studied yet. In this study, we have proposed a detailed mechanism for how the extra titania layer with TiCl4 provides high surface area and porosity to improve the adsorption of GQDs and dye. Moreover, the electron transport analysis revealed that the treatment reduced the electron recombination rate and increased the electron injection efficiency up to 73.8%, leading to a high Jsc and longer electron lifetime in the DSSC. Additionally, a performance comparison study with other types of GQDs under TiCl4 treatment was also investigated in this work.

Impact of the bilayer electron transport layer in the donor acceptor bulk heterojunctions for improved inverted organic photovoltaic performance

Functionalization at interface of the electron transport layer and the organic polymeric donor and non-fullerene acceptor bulk heterojunction layer in photovoltaic devices that have an inverted structure, is a unique strategy for improving performance. Here we demonstrate improved interfacial nanomorphology of the well-known PTB7-Th donor and IEICO-4F acceptor bulk heterojunction (BHJ) on an atomic layer deposited (ALD) ultrathin titanium oxide (TiO2) passivated sol–gel grown zinc oxide (ZnO) electron transport bilayer and highlight how this is correlated to the overall organic photovoltaic device performance. Synchrotron-based grazing incidence wide-angle X-ray scattering (GIWAXS) has been used to demonstrate an enhanced face-on conformation within the BHJ with highly crystalline ZnO/TiO2/BHJ layers and this is greatest for the very thinnest of TiO2 layers on ZnO (ZnT1), from just two deposition cycles, relative to both four (ZnT2) and eight (ZnT3) cycles. Photovoltaic devices with BHJs grown over ZnT1, showed an overall average increase of 30.3 ± 0.5 % in the power conversion efficiency (PCE 10.3 ± 0.5 %), a 14.3 ± 1 % increase in the fill-factor, FF (60.1 ± 1 %), 2.9 ± 0.05 % improvement in Voc (0.70 ± 0.05 mV) and 13.6 ± 0.5 % higher JSc (24.2 ± 0.5 mA/cm2), compared to the control device,with a best efficiency of 11.1 ± 0.5 % PCE, 61.9 ± 1 % FF, 0.70 ± 0.5 mV Voc and 25.0 ± 0.5 mA/cm2Jsc. We conclude that the molecular crystal conformation of the organic donor acceptor BHJ layer can be partly controlled through the ETL along with an enhanced organic inorganic interface which strongly influences the OPV performance.

Benzotriazole‐Based Polymer Acceptor for High‐Efficiency All‐Polymer Solar Cells with High Photocurrent and Low Voltage Loss

AbstractThe power conversion efficiencies (PCEs) of all‐polymer solar cells (all‐PSCs) have already exceeded 17%. However, the limited absorption range of an all‐polymer system results in significantly reduced short‐circuit current density (Jsc), which eventually influences the PCE improvement. To broaden the light absorption of polymer acceptors, herein, benzotriazole is introduced in the core unit of small molecule acceptors and thus two narrow‐bandgap polymer acceptors named PTz‐BO and PTz‐C11 featuring the same molecular backbone and different side‐chain length are synthesized. Compared with PTz‐C11, the PTz‐BO based‐all PSCs deliver a slightly reduced Jsc, a large open‐circuit voltage (Voc) and a low voltage loss below 0.50 V. Moreover, ternary all‐PSCs are constructed by introducing PTz‐C11 as a guest component. Benefiting from the reduced recombination, improved exciton generation and dissociation, and balanced charge transport, a high efficiency of 16.58% is obtained for the ternary all‐PSCs, with a high Jsc over 25 mA cm−2 without sacrificing the Voc. Such result represents the highest efficiency reported for benzotriazole‐based all‐PSCs in the literature thus far. This work demonstrates the great potential of benzotriazole for the synthesis of efficient narrow‐bandgap polymer acceptors.

Donor End-Capped Alkyl Chain Length Dependent Non-Radiative Energy Loss in All-Small-Molecule Organic Solar Cells.

A critical bottleneck for further efficiency breakthroughs in organic solar cells (OSCs) is to minimize the non-radiative energy loss (eΔVnr ) while maximizing the charge generation. With the development of highly emissive low-bandgap non-fullerene acceptors, the design of high-performance donors becomes critical to enable the blend with the electroluminescence quantum efficiency to approach or surpass the pristine acceptor. Herein, by shortening the end-capped alkyl chains of the small-molecular donors from hexyl (MPhS-C6) to ethyl (MPhS-C2), the material obtained aggregation that wasinsensitive to thermal annealing (TA) along withcondensed packing simultaneously. The former leads to small phase separation and suppressed upshifts of the highest occupied molecular orbital energy level during TA, and the latter facilitates its efficient charge-transport at aggregation-less packing. Hence, the ΔVnr decreases from 0.242 to 0.182V, from MPhS-C6 to MPhS-C2 based OSCs. An excellent PCE of 17.11% is obtained by 1,8-diiodoctane addition due to almost unchanged high Jsc (26.6mA cm-2 ) and Voc (0.888V) with improved fill factor, which is the record efficiency with the smallest energy loss (0.497eV) and ΔVnr (0.192V) in all-small-molecule OSCs. These results emphasize the potential material design direction of obtaining concurrent TA-insensitive aggregation and condensed packing to maximize the device performances with a super low ΔVnr .

Novel tert-butylated spirobifluorene -based organic sensitizers for dye-sensitized solar cells

Six organic sensitizers were synthesized starting from readily available reagent biphenyl. The introduction of tert-butylated spirobifluorene unit as the central building block was targeted for suppressing the dye-aggregation and improving the thermal/photo-stability and solubility. As a result, no obvious aggregations were observed in the absorption spectra of TM2, TM3, TM4 and TM6 sensitized TiO2 films. The higher Jsc,Voc and η (>5%) values of the TM6, TM3 and TM2 sensitized devices as compared with those of the devices based on TM1 and TM5 demonstrated the beneficial influence of weak or no aggregation. High thermal-stability and photo-stability for six dyes have been achieved. The electron lifetimes of TM2 and TM3 are over 122 ms, which are longer than those of many reported dyes. In addition, TM3 showed a very high molar extinction coefficient in visible region (5 × 104 M−1cm−1) due to the increase of the relative number of triphenylamine unit in chromophore.

(Invited, Digital Presentation) Photovoltaic Applications Using Energy Transfer Characteristics from Quantum Dots

Silicon-related materials are most commonly used in solar cells and become now an invaluable material. However, a reported maximum energy conversion efficiency of Si solar cell is close to reaching its theoretical limits. To further improve the cell performance and create new functions, it will become increasingly important to functionalize Si materials using nanostructures. One- and zero-dimensional Si nanostructures called Si nanowires (SiNWs) and Si quantum dots (Si QDs) are increasingly being used as new solar cell materials. Our group has shown that the conversion efficiency of solar cells can be increased by the non-radiation energy transfer (NRET) from Si QDs [1]. Recently, research has been developed on compound semiconductor QDs and perovskite QDs, and the conversion efficiency has been successfully increased [3-7].n-type SiNW arrays were fabricated by electroless etching and Bosch & nanoimprint lithography followed by CVD process. The CVD process was performed to form p-type Si layer for pn homojunction. Hybrid heterojunction cells of PEDOT:PSS and n-SiNWs were also fabricated. Passivation by ozone and hydrogen were applied to improve the solar cell properties [2]. After the cell fabrications, the solar cells were coated with Si QDs, CdZnS/ZnS QDs, CdZnSe/ZnS QDs and perovskite QDs. The fabrication methods and conditions of QDs have been reported elsewhere [1-7]Energy transfer effects such as NRET are new ways of increasing solar cell efficiency. To effectively use the NRET effect, the surface of Si QDs should be fully passivated by ligand molecules. The NRET process is a highly distance-dependent phenomenon, and its dependence on the length of the passivation ligands clearly showed this. NRET efficiency was increased by shortening the ligand length from 1-octadecene to 1-octene, resulting in higher JSC, ultimately providing higher energy conversion efficiency. The efficiency was increased about 1-2 % by adding SiQDs. We also observed the same effect for CdZnS/ZnS QDs, CdZnSe/ZnS QDs and perovskite CsPbCl3 QDs. In these cases, in addition to the NRET effect, the radiative energy transfer (RET) effect also contributes to the increase in conversion efficiency.

Cathode Interface Layer Based on Organosilica Nanodots for Efficient and Stable Inverted Organic Solar Cells

The interface layer greatly affects the performance of organic solar cells (OSCs). In this paper, we selected an amino-containing silane molecule (AEEA) and four fluorescein molecules with different functional groups to prepare a series of cathode interface materials based on organosilica nanodots (OSiNDs) by one-step hydrothermal synthesis, in order to research the impact of functional groups on the performance of OSC devices. The good film crystallinity and carrier mobility without high-temperature annealing endowed the OSCs with high Voc and Jsc, and the best efficiency of 15.91% was reached with the OSi-ErB cathode interlayer. Moreover, compared with ZnO devices, OSiND-based devices showed highly improved light stability after UV irradiation.

Asymmetric Non-Fullerene Small Molecule Acceptor with Unidirectional Non-Fused π-Bridge and Extended Terminal Group for High-Efficiency Organic Solar Cells.

We designed and synthesized an asymmetric non-fullerene small molecule acceptor (NF-SMA) IDT-TNIC with an A–D–π–A structure, based on an indacenodithiophene (IDT) central core, with a unidirectional non-fused alkylthio-thiophene (T) π-bridge, and 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile (NIC) extended terminal groups. IDT-TNIC molecules still maintain a good coplanar structure, which benefits from the non-covalent conformational locks (NCL) between O···S and S···S. The asymmetric structure increases the molecular dipole moment, and the extended terminal group broadens the absorption of the material, resulting in an excellent photovoltaic performance of IDT-TNIC. The photovoltaic device, based on PBDB-T:IDT-TNIC, exhibits an energetic PCE of 11.32% with a high Voc of 0.87 V, high Jsc of 19.85 mA cm−2, and a low energy loss of 0.57 eV. More importantly, IDT-TNICs with asymmetric structures show a superior property compared to symmetric IDT-Ns. The results demonstrate that it is an effectual strategy to enhance the properties of asymmetric A–D–π–A-based NF-SMAs with non-fused NCL π-bridges and extended terminal groups.

Investigation on the performance of nanostructure TiO2 bi-layer as photoanode for dye sensitized solar cell application

The photoanodes in dye-sensitized solar cells with two different morphologies such as one dimensional hydrothermally synthesized rutile nanorods and nanoparticles of TiO2 were utilized for improving the short circuit current density of the device. The synergistic effect of both the structures offer high Jsc by providing better pathway for the electron transportation through one dimensional nanorod morphology and efficient light absorption due to more dye adsorption on the mesoporous nanoparticles.With this, the condensation reaction mechanism for the formation of TiO2 rutile nanorod structure is elucidated along with FESEM analysis. The Field Emission Scanning Electron Microscope images confer the presence of highly oriented and vertically aligned nanorods. X-Ray Diffraction and RAMAN Spectroscopic studies confirm the crystalline nature of synthesized bi-layer film and it was observed to be a mixture of anatase and rutile phase of TiO2. The absorption and emission properties for the synthesized samples were studied using UV–Vis and Photoluminescence spectroscopy. The efficiency of the solar cells with the photo anodes of Nanorods, Nanoparticles and Nanorods/Nanoparticles bi-layer were found to be 0.30%, 4.41% and 4.23% respectively. Electrochemical Impedance Spectroscopic studies have done to check the charge transfer properties of the fabricated devices.

Non-fused-ring asymmetrical electron acceptors assembled by multi-functional alkoxy indenothiophene unit to construct efficient organic solar cells

Due to the complicated synthesis routes of ladder-typed fused ring small molecule acceptors (SMAs), simple non-fused-ring SMAs have been received attention. However, their photovoltaic properties have not made great progress due to the subtle crystallinity and intramolecular interaction. In this work, in order to advance photovoltaic properties, a type of non-fused-ring asymmetrical SMAs with an A-D-D'-A framework, named as IOMe-4Cl and IOEH-4Cl, was primarily designed and synthesized with a multifunctional alkoxy indenothiophene (INT) unit assembled with a classic dithienocyclopentadiene (DTC) unit as an electron-donating D-D' central build. The influence of asymmetric structure, non-covalent bond and alkoxy chain from the alkoxy INT unit on optical, electrochemical and photovoltaic properties was systemic studied. It was found that both SMAs exhibited strong near infrared absorption at about 900 nm. In comparison to the IOMe-4Cl with methoxy, the IOEH-4Cl with 2-ethyl-hexyloxy exhibited better regular film morphology and more suitable frontier orbital energy level with polymer PM6. As a result, IOEH-4Cl exhibited better photovoltaic properties than IOMe-4Cl in the solution-processing binary OSCs using polymer PM6 as donor material. A compelling PCE of 13.67% with high Jsc of 23.00 mA cm−2, Voc of 0.85 V and FF of 70.19% was obtained for the PM6:IOEH-4Cl based binary cells. This work clearly states that the multifunctional alkoxy INT is an appealing unit to construct high-performance non-fused-ring asymmetric SMAs by asymmetric unit, non-covalent bond and alkoxy chain effect.

New Bithiophene Extended IDIC-Based Non-Fullerene Acceptors and Organic Photovoltaics Thereof.

We developed new bithiophene extended electron acceptors based on m-alkoxythenyl-substituted IDIC with three different end groups, named as IDT-BT-IC, IDT-BT-IC4F, and IDT-BT-IC4Cl, respectively. The ultraviolet absorption maximum was redshifted and the bandgap was decreased as the strong electron accepting ability of the end group increased. A differential scanning calorimetry thermogram analysis revealed that all the new acceptors have a crystalline character. Using these acceptors and a bulk heterojunction structure using PBDB-T, inverted organic photovoltaic (OPV) devices were fabricated, and their performance was analyzed. Due to the red shift of the electron acceptors, the OPV active layer particularly, which was derived from IDT-BT-IC4F, exhibited increased absorption at long wavelengths over 800 nm. The OPV prepared using IDT-BT-IC exhibited a short-circuit current density (Jsc) of 2.30 mA/cm2, an open-circuit voltage (Voc) of 0.95 V, a fill factor (FF) of 45%, and a photocurrent efficiency (PCE) of 1.00%. Using IDT-BT-IC4F, the corresponding OPV device showed Jsc = 8.31 mA/cm2, Voc = 0.86 V, FF = 47%, and PCE = 3.37%. The IDT-BT-IC4Cl-derived OPV had Jsc = 3.00 mA/cm2, Voc = 0.89 V, FF = 29%, and PCE = 0.76%. When IDT-BT-IC4F was used as the electron acceptor, the highest Jsc and PCE values were achieved. The results show that the low average roughness (0.263 nm) of the active layer improves the extraction of electrons.

Electrode sticker for electrode lamination process enables highly durable inverted organic solar cells

Organic solar cells (OSCs) have attracted great interest in recent years owing to such features as low cost, light weight, and flexibility. The top electrodes of OSCs are generally fabricated by vapor deposition on organic layers. Recently, electrode lamination has emerged as a cost-effective process for the fabrication of top electrodes of OSCs because it does not damage organic thin layers. However, problems abound, including the low short-circuit current density (JSC) and the poor device durability of the resulting OSCs, which are due to the weak contact between the laminated electrode films and the organic layers. Herein we report an electrode sticker that can be firmly attached to an organic layer by thermocompression to realize electrode sticker-laminated OSCs with good JSC and device durability. The electrode sticker-laminated OSCs showed high JSC that approached that of electrode-sublimated OSCs, and their PCE values remained unchanged and were 98% of the maximum value after continuous photo-irradiation for 100 h under ambient conditions. The electrode sticker can be used to fabricate low-cost OSCs with good performance and durability for practical applications.

Fused-ring acceptors based on quinoxaline unit for highly efficient single-junction organic solar cells with low charge recombination

Two non-fullerene small molecule acceptors (TFQ-F and TFQ-Cl) based on quinoxaline unit were designed and synthesized for efficient organic solar cells (OSCs). These two acceptors showed intense absorption up to 900 nm and high thermal stabilities with decomposition temperatures over 360 °C due to their fused-ring skeletons. TFQ-F and TFQ-Cl are the A-D-A′-D-A type acceptors (A/A′ for acceptor unit and D for donor unit). TFQ-F and TFQ-Cl have the same D-A′-D fragment, which was flanked with different ending groups. The effect of different ending groups on their photophysical properties, electrochemical behaviors, micro-structures and charge recombination properties of active layers, and device performance were investigated systematically. PM6 with the complementary absorption to the two acceptors was used as the donor material. The pristine PM6:TFQ-F blend films displayed the optimal morphologies as revealed by AFM and TEM measurement. Organic solar cells based on PM6:TFQ-Cl blend film showed high JSC of 25.19 mA/cm2 and PCE of 13.2%. The Voc, JSC and PCE for PM6:TFQ-F film based device were 0.857 V, 23.70 mA/cm2 and 13.51%, respectively. The dependence of VOC/JSC on various light intensities indicated that PM6:TFQ-F/Cl based device had low charge recombination.