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Synthesis and characterization of novel benzodithiophene-fused perylene diimide acceptors: Regulate photovoltaic performance via structural isomerism
摘要： Two isomeric benzodithiophene-fused perylene diimides, BPDI-1 and BPDI-2, are designed and synthesized via photo-induced ring-closure reaction between perylene diimide (PDI) acceptor and both isomeric benzodithiophene donor cores, including benzo[2,1-b:3,4-b']dithiophene (BDP) and benzo[1,2-b:4,3-b']dithiophene (BdT). The effect of structural isomerism on the molecular geometry, absorption, energy level, film morphology as well as photovoltaic performance is comparatively studied. It is found that the variation of the S atom substituted position in the donor cores results in distinct molecular geometries for the newly-developed BPDI-1 and BPDI-2 acceptors. Compared with BDP-containing BPDI-1, the incorporation of BdT core endows BPDI-2 with a remarkably enhanced backbone distortion. When blended with the commercially available polymer donor (PTB7-Th), such twisted structure feature for the BPDI-2 acceptor plays a key role in reducing molecule aggregation, which is helpful for the enhancements of short-circuit current density and photovoltaic efficiency effectively. As a result, non-fullerene solar cells fabricated from BPDI-2 acceptor achieve higher photovoltaic efficiency (4.44%) than that of BPDI-1 (2.98%), mainly benefited from superior short-circuit current density. This work provides us comparative understanding of isomeric geometry and device performance.
关键词： Benzodithiophene,Molecular geometry,Non-fullerene organic solar cells,Perylene diimide derivatives
更新于2025-11-19 16:56:42
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Efficient Modulation of End Groups for the Asymmetric Small Molecule Acceptors Enabling Organic Solar Cells with over 15% Efficiency
摘要： Non-fullerene organic solar cells (OSCs) have attracted tremendous interest and made an impressive breakthrough, largely due to advances in high-performance small molecule acceptors (SMAs). The relationship between short-circuit current density (JSC) and open-circuit voltage (VOC) is usually shown as one falls and another rises. Controlling the trade-off between JSC and VOC to harvest high power conversion efficiencies (PCEs) still remains as a challenge. Herein, dithieno[3,2-b:2?,3?-d]pyrrole (DTP) based asymmetric SMAs with different chlorinated dicyanoindanone-based end groups, named TPIC, TPIC-2Cl and TPIC-4Cl, are designed and synthesized. These asymmetric acceptors exhibit remarkable red-shifted absorption profile, while energy levels are simultaneously down-shifted when the numbers of chlorine atoms alter from 0, 1 to 2, due to the gradually improved electronegativity. As a result, PM7: TPIC-4Cl based OSCs achieved a champion PCE of 15.31%, which is the highest PCEs for non-fullerene binary OSCs based on asymmetric SMAs. The superiority of PM7: TPIC-4Cl system consists of the balanced charge transport, favorable phase separation, efficient exciton dissociation and extraction, coupled with remarkable π–π stacking and crystallinity of the SMAs. Our results highlight the important strategy of asymmetric molecular design to optimize the trade-off between VOC and JSC, reaching a high PCE.
关键词： asymmetric molecular design,small molecule acceptors,chlorinated dicyanoindanone-based end groups,Non-fullerene organic solar cells,power conversion efficiencies
更新于2025-09-19 17:13:59
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High-Efficiency Nonfullerene Organic Solar Cells Enabled by 1000 nm Thick Active Layers with a Low Trap-State Density
摘要： The high-efficient organic solar cells (OSCs) with thicker active layers are potential candidates for large-area solar panels fabrication. The low charge carrier mobility of the photoactive materials has been identified as the major problem hindering photovoltaic performance of the thick-film OSCs. In this study, high performance of ultra-thick film organic solar cells employing a non-fullerene acceptor BTP-4Cl and a polymer donor PBDB-TF is demonstrated. Two blends (PBDB-TF:BTP-4Cl and PBDB-TF:IT-4F) show comparable mobilities and excellent photovoltaic characteristics in thin-film devices; while in the 1000-nm-thick devices, although they both exhibit desirable and balanced mobilities, the PBDB-TF:BTP-4Cl-based blend possesses lower trap-state density than the IT-4F-based counterpart, leading to lower trap-assist recombination, longer carrier lifetime, and thus a much higher short circuit current density in the device. As a result, the BTP-4Cl-based 1000-nm-thick OSC achieves a remarkable PCE of 12.1%, which greatly outperforms the IT-4F-based devices (4.72%). What is more, for a 1000-nm thick device with active area of 4 cm2, a promising efficiency of 10.1% was obtained, showing its great potential in future large-scale production.
关键词： trap-state density,ultra-thick active layers,high efficiency,non-fullerene organic solar cells,charge carrier mobility
更新于2025-09-19 17:13:59
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Improving Performance of Non-fullerene Organic Solar Cells over 13% by Employing Silver Nanowires Doped PEDOT:PSS Composite Interface
摘要： Ag NWs/PEDOT:PSS composite was prepared by a facile solution-processing method, and was employed as anode interface in non-fullerene organic solar cells (OSCs). With the presence of Ag NWs (5%, v/v%)/PEDOT:PSS interfacial layer, a high power conversion efficiency (PCE) up to 13.53% was achieved based on PBDB-T-2Cl:IT-4F photoactive layer system, much higher than the efficiency of the controlled counterpart device with pristine PEDOT:PSS as anode modifier. Simultaneous enhancements in short-circuit current and fill factor were observed, in comparison to the case of pristine PEDOT:PSS interface, due to the improved electrical conductivity of Ag NWs/PEDOT:PSS composites accompanied by the increased work function for a better matching with ITO counter electrode, which facilitated the increased charge transmission, and the reduced charge recombination at the anode/photoactive interface for the improved device performance. The results clearly revealed that Ag NWs/PEDOT:PSS composite interface is beneficial to improve the charge extraction and in favor of realizing highly efficient non-fullerene OSCs.
关键词： composite interface,electrical conductivity,Ag nanowires,recombination,Non-fullerene organic solar cells
更新于2025-09-19 17:13:59
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Polyolefin Elastomer as the Anode Interfacial Layer for Improved Mechanical and Air Stabilities in Non-fullerene Solar Cells
摘要： Despite the breakthroughs in power conversion efficiency (PCE) values of organic solar cells (OSCs), the other important issue concerns stability, which is urgently needed to be resolved for potential commercialization. A commercial and chemically stable polyolefin elastomer (POE) was incorporated into high-performance PBDB-T:ITIC, PM6:IT-4F and PM6:Y6 non-fullerene systems to serve as the anode interfacial layer, affording remarkably improved mechanical and air stabilities when compared with those of the most studied MoO3 interfacial layer. The POE was found to selectively transport holes rather than electrons, due to the upshifted surface contact potential of active layer and the better ohmic contact between active layer and electrode. The POE serving as an encapsulating layer is supposed to suppress the penetration of water and oxygen in addition to the diffusion of Ag atoms into active layer. After storing in an air environment with a humidity of approximately 70% for 150 days, the PCE of the device based on PM6:IT-4F with the POE anode interfacial layer decreased from 11.88% to 9.60%, retaining 80.8% of its original PCE value. The device using MoO3 as the anode interfacial layer showed a PCE value that was sharply reduced from 12.31% to 2.98% after storing for only 30 days. The POE could be potentially useful for flexible and large-scale device fabrication, accelerating the commercialization of OSCs.
关键词： stability,polyolefin elastomer,non-fullerene,organic solar cells,interfacial layer
更新于2025-09-19 17:13:59
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Wide-Band-Gap Phthalimide-Based D-π-A Polymers for Nonfullerene Organic Solar Cells: The Effect of Conjugated π-Bridge from Thiophene to Thieno[3,2- <i>b</i> ]thiophene
摘要： Conjugated polymers with D-π-A backbone structures have been intensively investigated and have largely promoted the rapid progress of organic solar cells (OSCs). However, as one of the simplest electron-accepting (A) units, phthalimide (PhI), only attracts less attention to construct promising D-π-A photovoltaic polymers in OSC community. Thus the correlations between the chemical structure-optoelectronic properties-photovoltaic performance need to be systematically investigated. Here, we combined the PhI moiety with the electron-donating (D) unit benzodithiophene (BDT) to synthesize two D-π-A copolymers PE80 and PE81, where the π-bridge corresponds to the thiophene (T) and thieno[3,2-b]thiophene (TT) respectively. When blended with a low bandgap (Eg=1.33 eV) non-fullerene acceptor Y6, PE81 achieved a power conversion efficiency (PCE) of 10.21% with an open circuit voltages (VOC) of 0.90 V, which are much higher than those of PE80:Y6 device (PCE = 4.11% and VOC = 0.88 V). Our results indicate that PhI is also a promising electron-deficient unit to construct photovoltaic polymers and using TT π-bridge is simple strategy to improve the photovoltaic performance of D-π-A polymers.
关键词： non-fullerene organic solar cells,D-π-A backbone,Conjugated polymers,thieno[3,2-b]thiophene,phthalimide
更新于2025-09-12 10:27:22