- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Difluorobenzoxadiazole-based conjugated polymers for efficient non-fullerene polymer solar cells with low voltage loss
摘要： Two donor-acceptor (D-A) conjugated copolymers based on difluorobenzoxadiazole (ffBX) and oligothiophenes, i.e., PffBX-2T and PffBX-TT, were designed and synthesized for polymer solar cells (PSCs). Compared to the polymers based on difluorobenzothiadiazole (ffBT) units, the two ffBX-based polymers presented identical optical bandgaps (~1.62 eV), but lower highest occupied molecular orbital (HOMO) energy levels. Owing to the down-shifted HOMO levels, the PSCs based on PffBX-2T and PffBX-TT showed lower voltage loss, and the open-circuit voltage (Voc) was ~0.1 V higher than that of the devices with the ffBT-based polymer. As a result, higher photovoltaic performance was achieved for the devices based on the ffBX-based polymers. The power conversion efficiencies (PCEs) of the non-fullerene PSCs with PffBX-2T and PffBX-TT as the donor were 8.72% and 10.12%, respectively. The superior device performance of PffBX-TT resulted from the efficient exciton dissociation and charge transport as well as weak charge recombination, which could be ascribed to the favorable face-on packing of the conjugated backbones and the desired morphology in the blend film. Our study demonstrates that difluorobenzoxadiazole is a promising building block for constructing conjugated polymers for high-performance non-fullerene PSCs.
关键词： voltage loss,difluorobenzoxadiazole,alkylthiophene side chains,non-fullerene polymer solar cells
更新于2025-09-12 10:27:22
-
Di‐fluorinated Oligothiophenes for High‐Efficiency All‐Small‐Molecule Organic Solar Cells: Positional Isomeric Effect of Fluorine Substitution on Performance Variations
摘要： Three symmetrically di-fluorinated organic semiconductors (namely D5T2F-P, D5T2F-S, and D5T2F-T) containing rhodanine-flanked pentathiophene structures are synthesized and used as donors in all-small-molecule organic solar cells (ASM-OSCs) prepared with the small-molecule acceptor 2,2'-((2Z,2'Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC-4F). The different substitutional positions of the fluorine atoms (-F) in the conjugated backbone of the donor molecule leads to various material and photovoltaic properties being exhibited. Among the three isomers, the centrally-fluorinated D5T2F-P exhibits a redshifted absorption spectrum, downshifted highest occupied molecular orbital (HOMO) energy level, and improved miscibility with IDIC-4F in the blend films, all of which result in superior device performance. The power conversion efficiency (PCE) of the ASM-OSCs based on D5T2F-P:IDIC-4F reaches the impressive value of 9.36% with an open-circuit voltage (VOC) value of 0.86 V and a short-circuit current density (JSC) value of 16.94 mA/cm2, while those of D5T2F-S (6.11%) and D5T2F-T (5.42%) are much lower. In comparison, an ASM-OSC based on the non-fluorinated analogue DRCN5T fabricated under the same conditions exhibits poorer performance (8.03% with IDIC-4F), revealing a 16% enhancement in PCE achieved through backbone fluorination. To the best of our knowledge, the PCE of 9.36% is one of the highest efficiencies of oligothiophene-based ASM-OSCs reported in the literature to date.
关键词： organic solar cells,binding energy,small molecule donors,fluorination,non-fullerene
更新于2025-09-12 10:27:22
-
Effects of oxygen atoms introduced at different positions of non-fullerene acceptors on performance of organic solar cells with poly(3-hexylthiophene)
摘要： With the development of large-area fabrication technologies for organic solar cells (OSCs), poly(3-hexylthiophene) (P3HT) is the best chioce as photovoltaic donor polymer becasue it can be easily synthesized in the scale of kilogram with low cost. However, non-fullerene acceptors (NFAs) matching with P3HT for high performance OSCs are very rare. Herein, by introducing oxygen atoms into the side chains or fused-ring core of indaceno[1,2-b:5,6-b’]dithiophene (IDT), we synthesized two new A2-A1-D-A1-A2 type NFAs, where benzotriazole (BTA) and 2-(1,1-dicyanomethylene)rhodanine (RCN) were used as bridged A1 and terminal A2 respectively. The final NFAs, named as BTA43 and BTA53, show wider absorption spectra and enhanced inter-/intra-molecular interaction in comparison with their analogue BTA3 without oxygen atom. The photovoltaic devices based on P3HT:BTA43 and P3HT:BTA53 can achieve the high PCEs of 6.56% and 6.31% respectively, which are obvious higher than that of BTA3 (5.64%). Our results provide a simple and effective strategy to design promising NFAs to pair with classic photovoltaic polymer P3HT.
关键词： molecular engineering,photovoltaic,non-fullerene acceptors,organic solar cells,P3HT
更新于2025-09-12 10:27:22
-
A high-performance non-fullerene electron acceptor with bisalkylthiothiophene π-bridges for organic photovoltaics
摘要： A new non-fullerene small molecule acceptor IDT2ST-4F bearing a bisalkylthiothiophene unit as the p-bridge was designed and synthesized, which exhibited a low optical bandgap of 1.43 eV. The optimized organic solar cells based on PBDB-T:IDT2ST-4F gave a high power conversion efficiency (PCE) of 11.43% with a relatively low energy loss of 0.58 eV.
关键词： non-fullerene electron acceptor,power conversion efficiency,organic photovoltaics,bisalkylthiothiophene
更新于2025-09-12 10:27:22
-
Efficient polymer solar cells that use conjugated polyelectrolyte with a tetravalent amine-end side chain
摘要： Conjugated polyelectrolyte based on benzotriazole (BT) with tetravalent amine-end side chain and benzothiadiazole (BTz) conjugated alternating repeat units, named PBTBTz-TMAI was initially designed and synthesized. Fullerene- and non-fullerene-based polymer solar cells were fabricated using PBTBTz-TMAI as the cathode interlayer. Consequently, power conversion efficiencies of 8.4% and 10.5% were achieved for the fullerene PTB7:PC71BM-based and non-fullerene PBDB-T:ITIC-based single-junction devices, respectively. The enhanced performance is attributed to the appropriate energy level alignment of the active layer with PBTBTz-TMAI and the efficient electron transfer from the active layer to the cathode electrode.
关键词： cathode interlayer,non-fullerene,tetravalent amine-end,conjugated polyelectrolyte,polymer solar cells
更新于2025-09-12 10:27:22
-
PBDB-T and its derivatives: A family of polymer donors enables over 17% efficiency in organic photovoltaics
摘要： Due to the advantages such as being low cost, light weight, and flexible as well as having low toxicity, organic solar cells (OSCs) have attracted extensive interest. The field of OSCs progressed dramatically after the emergence of non-fullerene small molecule acceptors. In addition to the development of these acceptor materials, a key driver in the rapid progress of OSC research was the introduction of the PBDB-T polymer and its derivatives. In this review, we first give a brief overview of the structural features of PBDB-T congeners and the strategies used to design these polymers. The interesting aggregation effects of PBDB-T congeners in solution and solid-states are highlighted. Recent advances in the morphological understanding OSCs based on PBDB-T congeners are discussed using selected examples. In addition, the versatile applications of PBDB-T congeners in OSC devices, including interfacially modified binary, ternary and tandem devices, are also summarized. Importantly, we assess the energy loss and provide a meta-analysis of a library of high-performance PBDB-T type polymers, which are compared with other types of conjugated polymers. Finally, the remaining questions and the prospects of these exciting polymers are suggested.
关键词： organic solar cells,non-fullerene acceptors,photovoltaic performance,PBDB-T,polymer donors
更新于2025-09-12 10:27:22
-
Improved Efficiency in All-Small-Molecule Organic Solar Cells with Ternary Blend of Non-Fullerene Acceptor and Chlorinated and Non-Chlorinated Donors.
摘要： Ternary non-fullerene all-small-molecule organic solar cells (NFSM-OSCs) were developed by incorporating a non-fullerene acceptor (IDIC) and two structurally similar small molecular donors (SM and SM-Cl), where SM-Cl is a novel small molecular donor derived from the reported molecular donor SM. When doping 10% SM-Cl in SM:IDIC binary system, the power conversion efficiency (PCE) of ternary solar cell was dramatically increased from 9.39% to 10.29%. Characterization studies indicated that the two donors tend to form an alloy state, which effectively down-shifted the HOMO energy level of the donor, and thus promoting a higher open-circuit voltage. Interestingly, incorporating a third component (SM-Cl) with lower crystallinity was proven to facilitate the demixing between donors and acceptors, which was in contrary to the traditional findings of enhanced phase separation through incorporation of highly crystalline molecule. Although the morphological modulation had always been a bottleneck issue in NFSM-OSCs, the findings in this work indicated that the modulation on crystallinity deviation between donors and acceptors could be an effective method to further improve the performance of NFSM-OSCs, providing a new perspective on NFSM-OSCs.
关键词： alloy model,non-fullerene all-small-molecule solar cells,chlorinated molecular donor,ternary strategy,crystallinity modulation
更新于2025-09-12 10:27:22
-
Synthesis and photovoltaic investigation of 8,10-bis (2-octyldodecyl) -8,10-dihydro-9H-bisthieno [2 ', 3': 7.8; 3``, 2 '': 5.6] naphtho [2,3-d] imidazol-9-one based conjugated polymers using non-fullerene acceptor
摘要： Two donor -acceptor (D-A) conjugated polymers designed on same 8,10-bis (2-octyldodecyl)-8,10-dihydro-9H-bisthieno [2`,3`:7,8; 3”,2”:5,6]naphtho [2,3-d]imidazole-9-one donor and dissimilar acceptor units, i.e. benzothiadiazole BT (P104) and fluorinated benzothiadiazole (P105) were synthesized and investigated their photophysical and electrochemical properties. The influence of the incorporation of fluorine atoms into the benzothiadiazole (BT) acceptor moiety in the polymer backbone on the photovoltaic performance when combined with the low bandgap non-fullerene acceptor ITIC-F was explored. The polymer solar cells based on P105:ITIC-F exhibited higher PCE (10.65 %) as compared to P104 :ITIC-F (8.32 %), resulted from the improved values of all the photovoltaic parameters. High value of Voc is linked with the deeper highest occupied molecular orbital energy level of P105 and the larger values of both short circuit current and fill factor are endorsed to the efficient exciton separation into charge carriers and their subsequent transfer owing to the increased value of dielectric constant and reduced value of exciton dissociation and energy loss and promoted balanced charge transportation. The intra/interchain interaction can be modulated by F atom substitution in the BT unit, resulting reduction in π-π stacking distance and increase in the crystal coherence length, benefiting the charge transportation in the active layer. These results offer a simple effective approach to regulate the optical and electrochemical properties and therefore increase the overall photovoltaic response.
关键词： D-A conjugated copolymer,non-fullerene acceptor,Polymer solar cells,morphology
更新于2025-09-12 10:27:22
-
A medium-bandgap small molecule donor compatible with both fullerene and unfused-ring nonfullerene acceptors for efficient organic solar cells
摘要： Here we designed and synthesized a new small molecule donor DRC4TB with an alkylthiothienyl-substituted benzodithiophene as the core and 3-butyl rhodanine as the terminal group, which showed an optical bandgap of 1.87 eV. DRC4TB was compatible with both a fullerene acceptor (PC71BM) and an unfused-ring non-fullerene acceptor (HF-PCIC). The optimized DRC4TB:PC71BM and DRC4TB:HF-PCIC solar cells delivered comparable power conversion efficiencies (PCEs) of 8.53% and 8.68%, respectively.
关键词： small molecule donor,nonfullerene acceptor,organic solar cells,fullerene acceptor,power conversion efficiencies
更新于2025-09-12 10:27:22
-
An A–D–D–A-type non-fullerene small-molecule acceptor with strong near-infrared absorption for high performance polymer solar cells
摘要： An acceptor–donor–donor–acceptor (A–D–D–A)-type near-infrared non-fullerene small-molecule acceptor IDT2-DFIC with indacenodithiophene–indacenodithiophene (IDT2) as a donating core and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as electron withdrawing end groups has been synthesized. Compared to A–D–A-type small-molecule acceptor IDIC-4F, IDT2-DFIC exhibits a low optical bandgap of 1.42 eV with strong absorption in the 450–874 nm region, and upshifted energy levels as an electron acceptor. Furthermore, the IDT2-DFIC-based devices exhibited higher and more balanced charge transport and smoother surface morphology. The power conversion efficiency (PCE) of the IDT2-DFIC-based devices is 10.06%, which is higher than that of the IDIC-4F-based devices (5.17%). Our work provides an efficient molecular design strategy to construct small molecule acceptors with near-infrared absorption.
关键词： IDT2-DFIC,near-infrared absorption,A–D–D–A-type,non-fullerene small-molecule acceptor,polymer solar cells
更新于2025-09-12 10:27:22