Ternary PSCs Research Articles

Ternary polymer solar cells using two nonfullerene acceptors with cascading energy level and complementary absorptions

In this paper, we have fabricated ternary PSC with BTP-eC9 as the host acceptor, IT-M as the guest acceptor, and PM6 as donor. The optimized ternary PSC (PM6:BTP-eC9:IT-M ratio is 1:1.2:0.2) has the highest power conversion efficiency (PCE) of 17.06 % compared to the PM6:BTP-eC9 binary PSC (16.46 %) and PM6:L8-BO reference binary PSC (16.92 %). We systematically investigated the effect of blend acceptors on morphology, photovoltaic performance and charge carrier dynamics. After the addition of IT-M to PM6:BTP-eC9 binary film, the highest JSC (from 26.39 to 26.82 mA cm−2) was achieved for optimized ternary PSCs compared to PM6:BTP-eC9 binary PSC, which was attributed to the high efficiency of light absorption in the medium to long-wavelength region of IT-M. Shallower lowest unoccupied molecular orbitals (LUMO) level of IT-M enlarged the optical bandgap, which leads to an increase in the open-circuit voltage (VOC, from 0.86 V to 0.875 V). In addition, a small amount of IT-M improves the surface and bulk morphology and crystallinity of the ternary film. The ternary films shown high charge mobility ability. This work demonstrates that supplementing the light absorption and broadening the optical bandgap of PM6:BTP-eC9 binary films by IT-M as third component can effectively improve the PCE and obtain higher photovoltaic performance than that of PM6:BTP-eC9 binary PSCs and PM6:L8-BO reference binary PSCs.

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.

Single junction binary and ternary polymer solar cells-based D–A structured copolymer with low lying HOMO energy level and two nonfullerene acceptors

The power conversion efficiency of the ternary PSCs (16.32%) is higher than that for binary counterparts, i.e., 13.16% and 12.62% for P(DTB-BDD):DBTBT-IC and P(DTB-BDD):Y6, respectively.

New Wide Bandgap Conjugated D‐A Copolymers Based on BDT or NDT Donor Unit and Anthra[1,2‐b:4,3,bʹ:6,7‐cʺ]trithiophene‐8‐12‐dione Acceptor for Fullerene‐Free Polymer Solar Cells

AbstractTwo donor–acceptor (D‐A) copolymers, P128 and P129, containing benzodithiophene (BDT) and naphthiodithiophene (NDT) donor unit, respectively, and the alike anthra[1,2‐b:4,3,bʹ:6,7‐cʺ] trithiophene‐8‐12‐dione(A3T) as an acceptor unit, are synthesized. The P129 (NDT donor) exhibits enhanced chain planarity and linearity of backbone compared to P128 (BDT donor), which leads to a considerable increase in both the light‐harvesting ability and hole mobility. In addition to it, the incorporation of the NDT unit creates a strong modification in the morphology with a well‐mixed interpenetrating nanofibrillar network with an increased donor–acceptor interface in the P129:Y6 bulk heterojunction active layer that leads to a high short‐circuit current density and fill factor. The power conversion efficiency (PCE) of the improved polymer solar cells based on P128:Y6 and P129:Y6 is 6.25% and 14.55%, respectively. The negative HOMO offset (−0.02 eV) at P128/Y6 interface restricts the hole transfer from Y6 to P128 and results in low value of short‐circuit current and thereby poor PCE. Finally, the ternary PSCs are constructed with a weight ratio of 0.5:0.5 between P128 and P129 and the weight component of Y6 is kept constant and the PSC attains a PCE of 16.19%. This increase in the PCE can be attributed to the formation of semiconducting alloy based on P128 and P129 donors and the transformation of HOMO offset from negative (−0.02 eV for Y6/P128) to positive (0.04 eV for Y6/P128:P129).

High‐Performance Ternary Semitransparent Polymer Solar Cells with Different Bandgap Third Component as Non‐Fullerene Guest Acceptor

Ternary semitransparent polymer solar cells (ST‐PSCs) have great potential to simultaneously improve the power conversion efficiency (PCE) and average visible transmittance (AVT). Non‐fullerene acceptor IHIC was synthesized by a simple one‐step process under low cost and had an A‐D‐A structure similar to ITIC and IT‐4F. Ternary device based on PM6:Y6:IHIC (20%) demonstrated higher hole and electron mobility (2.78, 3.12 × 10−4 cm2 V−1 S−1) and more balanced charge transport properties (μe/μh = 1.12) than the host binary device, and the ternary ST‐PSC demonstrated a PCE of 12.18% and AVT of 27.07%. Ternary PSCs with 20% ITIC or IT‐4F also exhibited more balanced μe/μh ratios (1.31 and 0.85), but with slightly enhanced short‐current circuit density (JSC) and reduced AVT (23–24%), mainly owing to unavoidable absorption of third component in the visible region. Our conclusion in this work was that the little A‐D‐A non‐fullerene acceptor could improve ternary blend film morphology and charge transport channels and enhanced JSC and PCE, and PM6:Y6:IHIC (20%) with high AVT over 27% and PCE over 12% was more suitable in ST‐PSCs than PM6:Y6:ITIC/IT‐4F (20%).

Ternary polymer solar cells with iridium-based polymer PM6Ir1 as a donor and N3:ITIC-Th as an acceptor exhibiting over 17.2% efficiency

Ternary PSCs were fabricated with PM6Ir1 as donor, ITIC-Th and N3 as acceptors. The incorporation of ITIC-Th can effectively optimize phase separation and molecular arrangement, leading to a PCE enhancement from 16.27% to 17.22%.

Understanding the Effect of the Third Component PC71BM on Nanoscale Morphology and Photovoltaic Properties of Ternary Organic Solar Cells

Herein, PC71BM is used as the third component (the second acceptor) to improve the photovoltaic performance of the organic solar cells (OSCs) based on a low‐cost polymer donor PTQ10 and a nonfullerene small‐molecule acceptor Y6. The ternary OSCs based on PTQ10:Y6:PC71BM reach a higher power conversion efficiency (PCE) of 16.07% with enhanced short‐circuit current density and a better fill factor in comparison with the binary OSCs based on PTQ10:Y6, which is ascribed to the higher electron mobility, better charge extraction, and suppressed charge recombination of the ternary PSCs. The film morphology of the OSCs is studied by grazing‐incidence wide‐angle X‐ray scattering, photo‐induced force microscopy, and transmission electron microscopy, which reveals that with the treatment of additive (0.5% CN) and thermal annealing, the phase separation of Y6 is obviously enhanced, whereas no significant changes occur for that of PTQ10 component. Besides, the addition of PC71BM slightly lowers the ratio of the face‐on orientation in the blend film and attenuate the aggregation of acceptor Y6. In addition, compared with the binary PTQ10:Y6 OSC, the ternary device based on PTQ10:Y6:PC71BM shows better device stability, demonstrating a great potential for the practical application of ternary OSCs.

A small-molecule/fullerene acceptor alloy: a powerful tool to enhance the device efficiency and thermal stability of ternary polymer solar cells

A small-molecule/fullerene acceptor alloy improved the PCE and stability of PBDB-T/PC71BM/IDT-OT ternary PSCs.

Achieving 14.11% efficiency of ternary polymer solar cells by simultaneously optimizing photon harvesting and exciton distribution

The exciton distribution can be optimized by employing ternary strategy, which well supports the performance improvement of ternary PSCs.

High-efficiency ternary polymer solar cells employing the solid solution as the donor phase

Abstract The solid solutions comprising amorphous conjugated polymer PCDTBT and different fullerene derivatives, i.e. crystalline PC71BM and amorphous NC60BA, have been investigated. It is found that the solid solution based on NC60BA could produce more hole carriers at the room temperature due to a smaller activation energy from trap state to free carriers compared to that based on PC71BM. A higher hole carrier density could effectively fill traps and reduce the recombination loss during charge transport process. The solid solution based on PC71BM shows enhanced exciton dissociation probability at the solid solution/C60 heterojunction interfaces. With combining the advantages of both the solid solutions, a small amount of amorphous NC60BA was introduced into the PCDTBT:PC71BM bulk heterojunction structure and the ternary BHJ PSCs composed of PCDTBT, PC71BM and NC60BA were fabricated. The ternary PSCs display outstanding photovoltaic performance compared to the binary PCDTBT:PC71BM bulk heterojunction PSCs.

Ternary non-fullerene polymer solar cells with an efficiency of 11.6% by simultaneously optimizing photon harvesting and phase separation

A PCE of 11.6% is achieved in ternary PSCs by optimizing photon harvesting and phase separation of active layers.

Ternary nonfullerene polymer solar cells with efficiency >13.7% by integrating the advantages of the materials and two binary cells

By integrating the advantages of the materials and two binary PSCs into one cell, a PCE of 13.73% is achieved in ternary PSCs.

Two compatible nonfullerene acceptors with similar structures as alloy for efficient ternary polymer solar cells

In this work, we fabricated high efficient ternary PSCs based on two compatible non-fullerene acceptors (IDIC and ITIC) with similar chemical structures and one new D-A-type polymer (PSTZ) donor. By inserting ITIC into the binary PSTZ:IDIC system, the active layer show smooth and gradient energy levels, improved crystallinity and optimized morphologies, which results in efficient exciton separation, charge transport and collection. As a result, the optimal ternary PSCs based on PSTZ:ITIC:IDIC (1:0.1:0.9) exhibited a higher PCE of 11.1% with a Voc of 0.953V, Jsc of 17.4mAcm−2 and FF of 66.9% in comparison with those of binary PSC systems based on PSTZ:IDIC (PCE of 8.06%) or PSTZ:ITIC (PCE of 8.13%). These results indicate that combining two compatible nonfullerene acceptors with similar structures to fabricate ternary PSCs should be a promising strategy to enhance the photovoltaic performance of the PSCs.

A liquid crystal material as the third component for ternary polymer solar cells with an efficiency of 10.83% and enhanced stability

BTR as a nucleating agent is incorporated into PTB7-Th:PC71BM to optimize their molecular arrangement and phase separation. The PCE and stability of the ternary PSCs are simultaneously improved due to the optimized morphology.

Efficient ternary polymer solar cells with a parallel-linkage structure

We have successfully fabricated highly efficient parallel-linkage ternary PSCs with PTB7 and PBDT-TS1 as the donors and PC71BM as the electron acceptor. The optimum PCE achieved is 7.91% for the ternary PSCs with an 80 wt% PBDT-TS1 doping ratio in the donors.