Ternary Active Layers Research Articles

Ionized Phenanthroline Derivatives Suppressing Interface Chemical Interactions with Active Layer for High-efficiency Organic Solar Cells with Exceptional Device Stability.

The contact interface between the charge transport interlayer and the active layer is crucial for the non-fullerene organic solar cells (NF OSCs) to achieve high efficiency and long-term stability. In this study, two novel phenanthroline (Phen) derivatives, tbp-Phen and tbp-PhenBr, are developed as efficient cathode interfacial materials (CIMs). The larger steric hindrance substituents and the ionization of nitrogen atoms on the Phen framework jointly enable the tbp-PhenBr CIM with a stable film morphology and immensely suppress the detrimental interface chemical interactions with the NF active layer. Consequently, tbp-PhenBr-based OSC achieves a higher efficiency (PCE=16.34%) than bathocuproine (BCP)-based control device (PCE=13.70%) using PM6:Y6 as the active layer. More importantly, the tbp-PhenBr-based device maintains 80% of its initial efficiency (T80) for 3264 h in dark conditions and 220 h after being heated at 85°C, significantly outperforming the BCP-based device. The tbp-PhenBr CIM also shows broad applicability across various binary and ternary active layer systems, affording a notable PCE of 19.49%. Additionally, the tbp-PhenBr CIM can be processed via a thermal evaporation technique and the prepared devices exhibit high reproducibility. This work provides innovative insights into the molecular design of the CIMs for stable and efficient NF OSCs.

High performance ternary organic photomultiplication detectors based on non-fullerene acceptor ITIC

To extend response spectrum to near infrared region, one non-fullerene acceptor ITIC was doped into P3HT:PC61BM blends, and the organic photomultiplication detectors (OPMDs) with structure of ITO/PEDOT:PSS/P3HT:ITIC:PC61BM(100:x:1, wt/wt/wt)/Al were prepared. The absorption and photoluminescence spectra of the active layer films and the current density-voltage characteristics of the devices were measured and analyzed, and the photomultiplication principle of the devices was studied. The results showed that a wide spectral response of 400–850 nm is realized in the ternary P3HT:ITIC:PC61BM active layer, and the external quantum efficiency, responsivity and specific detectivity of the ternary OPMDs based on P3HT:ITIC:PC61BM are all larger than those of the binary ones based on P3HT:PC61BM, and a maximum external quantum efficiency of 1113.71 %, specific detectivity of 6.42 × 1013 Jones and photoresponsivity of 762.99 A/W are obtained at 850 nm and under −16 V bias when the ITIC mass ratio in the ternary active layer is 4 % (i.e., x = 4). Such a considerable performance can be due to the fact that doping ITIC into P3HT:PC61BM can widen absorption spectrum of active layer to near infrared area, and increase electron trap density and exciton dissociation interfaces in active layer and create cascade energy levels for better carrier transport.

Boosting the Efficiency of Perovskite/Organic Tandem Solar Cells via Enhanced Near-Infrared Absorption and Minimized Energy Losses.

The compatibility of perovskite and organic photovoltaic materials in solution processing provides a significant advantage in the fabrication of high-efficiency perovskite/organic tandem solar cells. However, additional recombination losses can occur during exciton dissociation in organic materials, leading to energy losses in the near-infrared region of tandem devices. Consequently, a ternary organic rear subcell is designed containing two narrow-bandgap non-fullerene acceptors to enhance the absorption of near-infrared light. Simultaneously, a unique diffusion-controlled growth technique is adopted to optimize the morphology of the ternary active layer, thereby improving exciton dissociation efficiency. This innovation not only broadens the absorption range of near-infrared light but also facilitates the generation and effective dissociation of excitons. Owing to these technological improvements, the power conversion efficiency (PCE) of organic solar cells increased to 19.2%. Furthermore, a wide-bandgap perovskite front subcell is integrated with a narrow-bandgap organic rear subcell to develop a perovskite/organic tandem solar cell. Owing to the reduction in near-infrared energy loss, the PCE of this tandem device significantly improved, reaching 24.5%.

Sequentially Deposited Elastomer‐Based Ternary Active Layer for High‐Performance Stretchable Organic Solar Cells

AbstractStretchable organic solar cells (OSCs) with high power conversion efficiency and good mechanical deformation are promising as power sources for wearable electronics. However, synergistic improvement of both photovoltaic efficiency and mechanical ductility is challenging for state‐of‐the‐art polymer donor: non‐fullerene acceptor (NFA)‐based photovoltaic active layers. Here, a high‐performance stretchable OSC with a power conversion efficiency of 16.54% and a crack‐onset strain of 26.38% by synergetic optimization film microstructure of sequentially deposited ternary active layer consisting of a polymer donor poly[2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b']dithiophene))‐alt‐5,5'‐(5,8‐bis(4‐(2‐butyloctyl)thiophen‐2‐yl)dithieno[3',2':3,4;2'',3'':5,6]benzo[1,2‐c][1,2,5]thiadiazole)] (D18), an NFA 2,2'‐((2Z,2'Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2‐g]thieno[2',3':4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene)bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalonitrile) (Y6), and an elastomer polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene (SEBS) is reported. Adding a low‐content solvent additive para‐xylene into main solvent carbon disulfide induces high‐density fibers networks with low crystallinity in bottom D18 layer, and this further suppresses the large phase separation between Y6 and SEBS in top layer. Moreover, incorporating a solid additive 1,3‐dibromo‐5‐chlorobenzene with better compatibility with Y6 can promote Y6 dispersions to form smaller ordered domains in SEBS matrix. Finally, the optimal ternary active layer shows significantly higher efficiency and stretchability, resulting in a large efficiency‐stretchability factor of 4.36%, which is among the best values for stretchable OSCs.

Numerical study of charge transport layers in inverted ternary organic photovoltaic cells

This study investigates the crucial role of charge transport layers in enhancing the performance of inverted organic photovoltaic cells (OPVs) through advanced numerical simulations using OghmaNano software. OPVs offer distinct advantages, including lightweight, flexibility, and potential cost-effectiveness compared to traditional silicon-based counterparts, making them pivotal for sustainable energy solutions. We evaluate the efficiency of inverted (iOPVs) employing binary (PM6:L8-BO) and ternary (PM6:D18:L8-BO) active layers, utilizing electron transport layers (ETLs) including ZnO, TiO2, and SnO2, and hole transport layers (HTLs) such as MoO3, PEDOT, and WO3. Results highlight ZnO with a 15 nm-thick layer combined with MoO3 HTL achieving an impressive efficiency of 18.89% in ternary devices, demonstrating the effectiveness of organic materials and ternary blends. The study demonstrates that TiO2 or SnO2 ETLs can compete effectively with ZnO ETLs, particularly when used at thinner thicknesses, and offers alternative fabrication methods. It suggests that employing thin ETL layers (15 ± 2 nm) could significantly enhance the performance of iOPV devices. Simulations are crucial for optimizing iOPV device configurations with thin ETL layers, enabling rapid prototyping and cost-effective exploration of material combinations and device architectures. These layers play a critical role in balancing charge carrier generation and transport efficiency, collectively maximizing device performance. Overall, the study underscores the pivotal role of simulations and optimized layer thicknesses in advancing OPV technology by refining manufacturing processes and accelerating the adoption of OPVs for sustainable energy solutions.

Regulating Phase Separation Kinetics for High-Efficiency and Mechanically Robust All-Polymer Solar Cells.

All-polymer solar cells (all-PSCs) possess excellent operation stability and mechanical robustness than other types of organic solar cells, thereby attracting considerable attention for wearable flexible electron devices. However, the power conversion efficiencies (PCEs) of all-PSCs are still lagging behind those of small-molecule-acceptor-based systems owing to the limitation of photoactive materials and unsatisfactory blend morphology. In this work, a novel terpolymer, denoted as PBDB-TFCl (poly4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo[1,2-b:4,5-b″]dithiophene-1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c″]dithiophene-4,8-dione-4,8-bis(4-chloro-5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene), is used as an electron donor coupled with a ternary strategy to optimize the performance of all-PSCs. The addition of PBDB-TCl unit deepens the highest occupied molecular orbital energy level, reducing voltage losses. Moreover, the introduction of the guest donor (D18-Cl) effectively regulates the phase-transition kinetics of PBDB-TFCl:D18-Cl:PY-IT during the film formation, leading to ideal size of aggregations and enhanced crystallinity. PBDB-TFCl:D18-Cl:PY-IT devices exhibit a PCE of 18.6% (certified as 18.3%), judged as the highest value so far obtained with all-PSCs. Besides, based on the ternary active layer, the manufactured 36 cm2 flexible modules exhibit a PCE of 15.1%. Meanwhile, the ternary PSCs exhibit superior photostability and mechanical stability. In summary, the proposed strategy, based on molecular design and the ternary strategy, allows optimization of the all-polymer blend morphology and improvement of the photovoltaic performance for stable large-scale flexible PSCs.

A Review of the Improvements in the Performance and Stability of Ternary Semi-Transparent Organic Solar Cells: Material and Architectural Approaches

In the past decade, considerable efforts have been made to develop semi-transparent organic solar cells (ST-OSCs). Different materials and architectures were examined with the aim of commercializing these devices. Among these, the use of ternary active layers demonstrated great promise for the development of efficient semi-transparent organic solar cells with the potential for future applications, including but not limited to self-powered greenhouses and powered windows. Researchers seek alternative solutions to trade-off between the power conversion efficiency (PCE) and average visible transmittance (AVT) of ST-OSCs, with photoactive materials being the key parameters that govern both (PCE) and (AVT), as well as device stability. Several new organic materials, including polymers and small molecules, were synthesized and used in conjunction with a variety of techniques to achieve semi-transparent conditions. In this review paper, we look at the working principle and key parameters of semi-transparent organic solar cells, as well as the methods that have been used to improve the performance and stability of ternary-based semi-transparent organic solar cells. The main approaches were concluded to be spectral enhancement and increments in the transparency of the active layer through band gap tuning, utilizing novel organic semi-conductors, optical engineering, and the design architecture of the active layers.

In Situ Removable Additive Assisted Organic Solar Cells Achieving Efficiency over 19% and Fill Factor Exceeding 81%

AbstractAdditive engineering can precisely regulate the bulk‐heterojunction active layer morphology with ideal domain size and purity, playing a critical role in development of organic solar cells (OSCs). Herein, two solid additives, 1,4‐dichlorobenzene (DCB) and 1‐chloro‐4‐iodobenzene (CIB), with low melting point (mp.) of ≈52 °C, are investigated comprehensively with comparison to 1,4‐diiodobenzene (DIB, mp. 131 °C). After spin‐coating, DIB residue is found in the as‐cast PM6:BTP‐eC9 based blend film, whereas the DCB and CIB are completely removed during the spin‐coating, showing in situ removable properties that enable convenient processing. In OSCs, the DCB‐ and CIB‐processed active layers afford power‐conversion efficiencies (PCEs) of 18.2% and 18.4%, respectively, all higher than that of 17.8% for DIB. Among the three solid additives, the CIB is most effective in enhancements of absorption coefficients of the donor and acceptor, affording fast and more balanced carrier transports, and suppressing recombination. Of particular note, the CIB can provide some universality as an in situ removable solid additive, based on its elevations of PCEs for several binary and PM6:D18‐Cl:L8‐BO ternary active layers. Impressively, a prominent PCE of 19.1% with a remarkable fill factor of 81.1% is achieved for the CIB‐processed ternary active layer. This work demonstrates the potential of in situ removable solid additive engineering in high‐efficiency OSCs.

Batch-Reproducible and Thickness-Insensitive Mesopolymer Zwitterion Interlayers for Organic Solar Cells

Zwitterionic polymers or small molecules are a class of widely used interlayer materials in organic solar cells (OSCs). It is challenging to develop such materials that combine good film-forming property, high batch-to-batch reproducibility, and broad thickness processing window in device applications. Herein, we designed and synthesized two self-doped conjugated mesopolymer zwitterions (CMZs), namely, MT2PDIMz and MT2PDINz (PDI = perylene-diimide, M = mesopolymer, T2 = dithiophene, Mz = imidazolium zwitterion, Nz = ammonium zwitterion). Both show good processability and effectively reduce the work function of metal electrodes. The substitution of imidazolium cations with ammonium cations on the side-chains can further modulate the solution assembly and self-doping effect of CMZs, enabling improved interfacial compatibility with active layers and higher electron mobility in MT2PDIMz. The versatility of CMZs interlayers for OSCs is confirmed with several binary and ternary active layers, affording efficiencies up to 19.01%. Notably, over 98% of the optimal efficiency is maintained as the thickness of the interlayers increases to 40 nm with good reproducibility.

Organic near‐infrared photodetectors with photoconductivity‐enhanced performance

AbstractOrganic near‐infrared (NIR) photodetectors with essential applications in medical diagnostics, night vision, remote sensing, and optical communications have attracted intensive research interest. Compared with most conventional inorganic counterparts, organic semiconductors usually have higher absorption coefficients, and their thin active layer could be sufficient to absorb most incident light for effective photogeneration. However, due to the relatively poor charge mobility of organic materials, it remains challenging to inhibit the photogenerated exciton recombination and effectively extract carriers to their respective electrodes. Herein, this challenge was addressed by increasing matrix conductivities of a ternary active layer (D–A–D structure NIR absorber [2TT‐oC6B]:poly(N,N′‐bis‐4‐butylphenyl‐N,N′‐bisphenyl)benzidin [PolyTPD]:[6,6]‐phenyl‐C61‐butyric acid methyl ester [PCBM] = 1:1:1) upon in situ incident light illumination, significantly accelerating charge transport through percolated interpenetrating paths. The greatly enhanced photoconductivity under illumination is intrinsically related to the unique donor–acceptor molecular structures of PolyTPD and 2TT‐oC6B, whereas stable intermolecular interaction has been verified by systematic molecular dynamics simulation. In addition, an ultrafast charge transfer time of 0.56 ps from the NIR aggregation‐induced luminogens of 2TT‐oC6B absorber to PolyTPD and PCBM measured by femtosecond transient absorption spectroscopy is beneficial for effective exciton dissociation. The solution‐processed organic NIR photodetector exhibits a fast response time of 83 μs and a linear dynamic range value of 111 dB under illumination of 830 nm. Therefore, our work has opened up a pioneering window to enhance photoconductivity through in situ photoirradiation and benefit NIR photodetectors as well as other optoelectronic devices.

Tandem organic solar cells with 20.6% efficiency enabled by reduced voltage losses.

Large voltage losses are the main obstacle for achieving high efficiency in organic solar cells (OSCs). Here we construct ternary OSCs by introducing an asymmetric small molecule acceptor AITC into PBDB-TCl : BTP-eC9 system and demonstrate the effectiveness in simultaneously decreasing energy disorder and non-radiative voltage losses. It is found that the introduction of AITC can modify domain size and increase the degree of crystallinity, which enhances open-circuit voltage and power conversion efficiency (19.1%, certified as 18.9%). Inspiringly, an output efficiency of 20.6% of the constructed tandem OSCs based on PBDB-TCl : AITC : BTP-eC9 ternary active layer output a recorded efficiency of 20.6% (certified as 20.3%), which is the highest value in OSCs field to date. This work demonstrates that decreasing the voltage losses by ternary strategy and constructing of tandem architecture are effective approaches towards improving photovoltaic performance.

Niobium-Carbide MXene Modified Hybrid Hole Transport Layer Enabling High-Performance Organic Solar Cells Over 19.

Niobium-carbide (Nb2 C) MXene as a new 2D material has shown great potential for application in photovoltaics due to its excellent electrical conductivity, large surface area, and superior transmittance. In this work, a novel solution-processable poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)-Nb2 C hybrid hole transport layer (HTL) is developed to enhance the device performance of organic solar cells (OSCs). By optimizing the doping ratio of Nb2 C MXene in PEDOT:PSS, the best power convention efficiency (PCE) of 19.33% can be achieved for OSCs based on the ternary active layer of PM6:BTP-eC9:L8-BO, which is so far the highest value among those of single junction OSCs using 2D materials. It is found that the addition of Nb2 C MXene can facilitate the phase separation of the PEDOT and PSS segments, thus improving the conductivity and work function of PEDOT:PSS. The significantly enhanced device performance can be attributed to the higher hole mobility and charge extraction capability, as well as lower interface recombination probabilities generated by the hybrid HTL. Additionally, the versatility of the hybrid HTL to improve the performance of OSCs based on different nonfullerene acceptors is demonstrated. These results indicate the promising potential of Nb2 C MXene in the development of high-performance OSCs.

18.7% Efficiency Ternary Organic Solar Cells Using Two Non-Fullerene Acceptors with Excellent Compatibility

In this work, a series of ternary organic solar cells (OSCs) were prepared with polymer PM6 as a donor and two non-fullerene materials, BTP-eC9 and ITIC-Th, with excellent compatibility as acceptors. The open-circuit voltage (VOC) of ternary OSCs is found to monotonically increase with increasing content of ITIC-Th, implying the formation of an alloying state between BTP-eC9 and ITIC-Th. Furthermore, the incorporation of ITIC-Th can effectively minimize energy loss, which effectively improves the VOC of ternary OSCs. Consequently, a remarkable power conversion efficiency (PCE) of 18.7% with a short-circuit current density (JSC) of 28.0 mA cm–2, a VOC of 0.87 V, and a fill factor (FF) of 77.0% is achieved from the optimal ternary OSCs with 15 wt % ITIC-Th in acceptors. Comprehensive characterizations show that the enhanced JSC and FF are likely due to enhanced photon harvesting, effective exciton dissociation, and balanced charge transport in the optimal ternary active layers. The findings provide a hopeful way to further improve the OSC performance by employing a ternary strategy with two compatible non-fullerene materials as acceptors.

Ambipolar Behavior of a Cu(II)–Porphyrin Derivative in Ternary Organic Solar Cells

Ternary architecture is a promising strategy to achieve high efficiency in organic solar cells. The alignment of third‐component frontier orbitals with those of donor and acceptor (D and A) is of essential importance. Herein, a new molecule VC11, consisting of a Cu(II)–porphyrin core linked to dicyanovinylene terminal acceptor units through (E)‐1,2‐di(thiophen‐2‐yl) ethene bridges, is described. The highest occupied molecular orbital and lowest unoccupied molecular orbital values of VC11 are −5.52 and −3.74 eV, respectively, lying between the corresponding values of PBDB‐T donor and Y6 acceptor, compounds used in the construction of the studied devices. The measured electron and hole mobilities reveal similar values, in the order of 10−4 cm2 Vs−1, indicating the ambipolarity of VC11, that can be used as donor or acceptor. The organic solar cells (OSCs) based on PBDB‐T:VC11, VC11:Y6, and PBDB‐T:Y6 show power conversion efficiencies (PCEs) of 10.84%, 7.89%, and 11.98%, respectively. VC11 is utilized along with PBDB‐T and Y6 to form a ternary active layer for assembling bulk heterojunction OSCs affording a remarkable PCE of 15.25%, significantly higher than those obtained for the corresponding binary devices. This enhancement of PCE originates from the additional charge separation offered by a cascaded energy‐level alignment and a fast charge transfer, due the ambipolarity of VC11.

Broadband Organic Ternary Bulk Heterojunctions Photodetector Based on Non-Fullerene Acceptor with Enhanced Flat-Spectrum Response Range from 200 to 1100 nm.

Both flat-spectrum responsivity and high external quantum efficiency (EQE) of bulk heterojunction organic photodetectors (BHJ OPDs) are greatly in demand and still challenging to realize from the ultraviolet (UV) to near-infrared (NIR) regions. In this article, conjugated polymer donor poly(3-hexylthiophene) (P3HT) and PTB7-Th are blended with a low band gap nonfullerene acceptor (NFA) IEICO-4F to form a ternary BHJ active layer, thereby forming a BHJ OPD with a broadband responsivity spectrum from UV to visible light to NIR region (200-1100 nm). Under 6 V voltage and in the range from 280 to 810 nm, the ternary BHJ OPD shows a relatively flat responsivity spectrum, and the highest responsivity is 1.348 A/W, which is 1.34 times that of the binary BHJ OPD. Specifically, the ternary BHJ OPD achieved the highest EQE at 285 nm and as high as 449.31%. In addition, the ternary OPD detectivity (D*) is 2.65 times that of the binary BHJ OPD. Therefore, ternary BHJ as an active layer provides an effective method to develop BHJ OPDs with an expanded response range, higher responsivity, improved EQE, and broadband spectrum with flat spectral response from the UV to NIR region.

Combination of highly photovoltaic and highly transparent materials enables record performance semitransparent organic solar cells

Semitransparent organic solar cells (ST-OSCs) are an important branch of organic solar cells, which have considerable application prospects in building photovoltaic, smart greenhouses, and clean energy vehicle skylights. However, a compromise between the power conversion efficiency (PCE) and the average visible transmittance (AVT) has been the obstacle in the field of ST-OSCs. Therefore, comprehensive consideration of PCE, AVT and the resulting light utilization efficiency (LUE), is very necessary to objectively evaluate the performance of a ST-OSC device. Herein, we report a facile strategy by combination of the advantages of the highly photovoltaic materials with highly transparent materials to construct high performance ternary active layer for ST-OSCs. Two ternary systems PM6:PCE10-2F:Y6 and PCE10-2F:PM6:Y6 are developed according to their host binary blends PM6:Y6 (w:w = 1:1.2) and PCE10-2F:Y6 (w:w = 1:2.5) respectively. The PCEs of the opaque and transparent devices are observed to be both improved in the ternary systems relative to their corresponding host systems, due to the complementary absorption, optimized morphology and charge dynamics. More importantly, combination of highly photovoltaic materials with highly transparent materials enables a well-balanced PCE and AVT, leading to significantly enhanced LUE. For PM6:PCE10-2F:Y6 devices, simultaneously improved PCE and AVT are obtained. Intriguingly, ST-OSC based on PCE10-2F:PM6:Y6 achieves an impressive PCE of 12.25 % and a high AVT of 36.57 %, which is the highest efficiency for the AVT over 30 %. A maximum LUE of 4.48 % is also a breakthrough of the ST-OSCs without complex photo-coupling layers. These findings demonstrate that combination of the high PCE system with high AVT system is a promising strategy for developing high performance ST-OSCs.

Boosts charge utilization and enables high performance organic solar cells by marco- and micro- synergistic method

A ternary solar cell is a typical strategy that can well compensate light absorption and effectively regulate energy levels and the morphology of active layers. However, the commonly used active materials have low relative dielectric constant, which is one of the important limitations for improving the photovoltaic performance of organic solar cells (OSCs). In this work, an insulating polymer MPFM with high relative dielectric constant is introduced into the ternary active layers to improve the performance of OSCs by synergistic effect of macro light utilization and micro interface modulation. The introduction of MPFM not only strengthened the dielectric constant of bulk heterojunctions but also enhanced the degree of crystallinity and adhesivity, promoted the exciton separation, suppressed charge recombination, and significantly accelerated charge transport. As a result with the addition of MPFM, an outstanding efficiencies of 18.21% and 18.53% are achieved for devices based on PM6:Y6:PC71BM and PM6:BTP-eC9:PC71BM, respectively. These results indicated that constructing the micro-PIN junction by using MPFM is an effective strategy to further improve the photovoltaic performance of OSCs.

2D/1A ternary blend system enables non-fused ring electron acceptor based polymer solar cells with improved photovoltaic parameters

Non-fused ring electron acceptors (NFRAs), whose central skeletons are selected from simple aromatic rings, have been developed to be the promising candidates to maintain a rational balance between cost and performance. In this work, a 2D/1A ternary blend system, with polymers PM6 and PTQ10 as the two donor components and small molecular BDDEH-4F as the NFRA, was designed for polymer solar cells (PSCs). Comparing with power conversion efficiencies (PCEs) of 12.16% and 8.28% for the PM6 and PTQ10 based binary active layers, respectively, the optimized PM6:PTQ10:BDDEH-4F = 0.85:0.15:1 ternary active layer could show improved photovoltaic parameters, giving a higher PCE of 13.04%. Based on Flory-Huggins interaction parameter estimations, PTQ10 is more miscible to the NFRA if compared with PM6, and thus the addition of PTQ10 in the ternary active layer would tune the morphology. Enhanced exciton dissociation, suppressed trap-assisted recombination, higher and more balanced charge mobilities, and optimized morphology were achieved for the ternary blend system, finally contributing to the improved photocurrent and fill factor. Polymer PTQ10 is a notable low cost donor. Therefore, the 2D/1A ternary strategy should provide a ternary active layer with cost saving advantage. • 2D/1A ternary active layer for non-fused ring electron acceptor. • The ternary solar cells showing PCE of 13.04%, higher than 8.28–12.16% for binary solar cells. • The ternary active layer provides cost saving advantage.

Fine-Tuned Morphology Based on Two Well-Miscible Polymer Donors Enables Higher Open-Circuit Voltage and Enhanced Stability for Highly Efficient Ternary All-Polymer Solar Cells.

Developing organic solar cells based on a ternary active layer is one of the most effective approaches to improve their photovoltaic performance. However, limited success has been achieved in all-polymer solar cells (all-PSCs). In this study, a ternary all-PSC with improved efficiency and stability is realized by using J71 as the third component to adjust the host system of PBDB-T:PG1. The deeper highest occupied molecular orbital (HOMO) energy level of J71 downshifts the mixed HOMO energy levels of donors. The two polymer donors (PD s) have good miscibility and present Förster resonance energy transfer. When blended with PG1, the optimized morphology is obtained, showing enhanced crystallinity but meanwhile slightly reduced phase separation with improved exciton dissociation and collection efficiency, suppressed charge recombination, and reduced energy loss (0.55eV). Combining the benefits mentioned above, the ternary all-PSC exhibits an excellent efficiency of 12.8% with simultaneously elevated open-circuit voltage (0.96V), short-circuit current density (18.4mAcm-2 ), and fill factor (72.2%). Moreover, the optimized ternary all-PSC shows improved storage and thermal stability. This study demonstrates that the utilization of a ternary all-polymer system based on two well-miscible PD s is an effective strategy to enhance the photovoltaic performance and stability of all-PSCs.

Non‐Fullerene Acceptor‐Based Nanomorphology Enhancement for Efficient Ternary Organic Solar Cells

Recently, the ternary active‐layer‐based organic solar cells have shown remarkable increment in the power conversion efficiency (PCE) by utilizing the synergistic effect of complementary absorption, band alignment, and nano‐scale morphology enhancement. Non‐fullerene acceptors (NFAs) are an important class of functional materials for the improved performance of ternary organic solar cells due to their role in improvising the light absorption and the morphology of the active layer. Here, the non‐fullerene (NF) molecule, NAI‐FN‐NAI (BO), is used as the third component in the bulk heterojunction of PTB7‐Th: PC71BM to fabricate the ternary organic solar cell. The magical number of the composition, i.e., 20% by weight of the NF in the ternary active layer resulted in the PCE of 8.1% devices, which is almost 35% higher efficiency than PTB7‐Th: PC71BM binary devices having the PCE of 6%. The enhanced efficiency is observed even though the lessened effect of complementary absorption and band alignment factors of the NF. Such an improved efficiency is attributed in ternary devices to the nano‐scale morphology enhancement. It could pave the way to realize the best possible bulk heterojunction blend to attain high PCE close to inorganic counterparts.