High-Performance All-Polymer Solar Cells Research Articles

Morphology Control Realizes Fast Charge Dissociation and Transport in High-Performance All-Polymer Solar Cells

Morphology Control Realizes Fast Charge Dissociation and Transport in High-Performance All-Polymer Solar Cells

Triggering the Donor-Acceptor Phase Segregation with Solid Additives Enables 16.5% Efficiency in All-Polymer Solar Cells.

All-polymer solar cells have attracted considerable research interest due to their superior morphological stabilities, stretchability, and mechanical durability. However, the morphology optimization of the all-polymer bulk heterojunctions remains challenging due to the two long conjugated polymer chains, limiting its power conversion efficiency. Herein, we focus on the donor-acceptor phase segregation of an all-polymer active layer composed of PM6/PY-IT, a state-of-the-art all-polymer combination, by the introduction of volatile solid additives. Especially with 1,3-dibromo-5-chlorobenzene (DBCl) as the processing additive, we could effectively tune the miscibility between PM6 and PY-IT and thus optimize the phase segregation of the polymer donor and acceptor. Due to the synergetic effects on the favorable phase segregation and desired donor-acceptor distribution, the DBCl-treated devices feature the evident improvement of charge transport and collection, accompanied by the suppressed trap-assisted charge recombination. We consequently achieved a champion device efficiency of 16.5% (16.4% averaged), which is a 13% improvement compared with the control device without DBCl (14.6%). Our results highlight the importance of altering the miscibility of the polymer donor-acceptor pairs for practical applications of high-performance all-polymer solar cells.

Polymerized A-DA’D-A type small-molecule acceptors for high performance all-polymer solar cells: progress and perspective

Polymerized A-DA’D-A type small-molecule acceptors for high performance all-polymer solar cells: progress and perspective

Biselenophene Imide: Enabling Polymer Acceptor with High Electron Mobility for High-Performance All-Polymer Solar Cells.

The shortage of narrow band gap polymer acceptors with high electron mobility is the major bottleneck for developing efficient all-polymer solar cells (all-PSCs). Herein, we synthesize a distannylated electron-deficient biselenophene imide monomer (BSeI-Tin) with high purity/reactivity, affording an excellent chance to access acceptor-acceptor (A-A) type polymer acceptors. Copolymerizing BSeI-Tin with dibrominated monomer Y5-Br, the resulting A-A polymer PY5-BSeI shows a higher molecular weight, narrower band gap, deeper-lying frontier molecular orbital levels and larger electron mobility than the donor-acceptor type counterpart PY5-BSe. Consequently, the PY5-BSeI-based all-PSCs deliver a remarkable efficiency of 17.77 % with a high short-circuit current of 24.93 mA cm-2 and fill factor of 75.83 %. This efficiency is much higher than that (10.70 %) of the PY5-BSe-based devices. Our study demonstrates that BSeI is a promising building block for constructing high-performance polymer acceptors and stannylation of electron-deficient building blocks offers an excellent approach to developing A-A type polymers for all-PSCs and even beyond.

Manipulating Polymer Backbone Configuration via Halogenated Asymmetric End-Groups Enables Over 18% Efficiency All-Polymer Solar Cells.

High-performance all-polymer solar cells (all-PSCs) deeply rely on the joint contributions of desirable optical absorption, adaptive energy levels, and appropriate morphology. Herein, two structural analogous polymerized small-molecule acceptors (PSMAs), PYFCl-T and PYF&PYCl-T, are synthesized, and then incorporated into the PM6:PY-IT binary blends to construct ternary all-PSCs. Due to the superior compatibility of PY-IT and PYFCl-T, theternary all-PSC based on PM6:PY-IT:PYFCl-T with 10 wt% PYFCl-T, presents higher and more balanced charge mobility, suppressed charge recombination, and faster charge-transfer kinetics, resulting in an outstanding power conversion efficiency (PCE) of 18.12% with enhanced Jsc and FF, which is much higher than that (PCE of 16.09%) of the binary all-PSCs based on PM6:PY-IT. Besides, the ternary all-PSCs also exhibit improved photostability. The conspicuous performance enhancement principally should give the credit to the miscibility-driven phase optimization of the donor and acceptor. These findings highlight the significance of polymer-backbone configuration modulation of PSMAs in morphology optimization toward boosting the device properties of all-PSCs.

Regioregular polymerized small-molecule acceptors for high-performance all-polymer solar cells

This review summarizes the recent advances of regioregular polymer acceptors based on SMAs for all-PSCs in the past three years, and the guidelines for future design of polymer acceptors are discussed.

Y-Series-Based Polymer Acceptors for High-Performance All-Polymer Solar Cells in Binary and Non-binary Systems

Y-Series-Based Polymer Acceptors for High-Performance All-Polymer Solar Cells in Binary and Non-binary Systems

Bright future of polymerizing small-molecule acceptors in realizing high performance all-polymer solar cells

Bright future of polymerizing small-molecule acceptors in realizing high performance all-polymer solar cells

Molecular Optimization on Polymer Acceptor Enables Efficient All-Polymer Solar Cell with High Open-Circuit Voltage of 1.10V.

Currently, rational design of polymer acceptors is desirable but there is still a challenge to develop high-performance all-polymer solar cells (all-PSCs). In this work, brominated thienyl-fused malononitrile-based monomer is employed to copolymerize with indacenodithiophene (IDT) and benzodithiophene (BDT)-based linking units to develop two polymerized small molecule acceptors (PSMAs) PIDT and PBDT, respectively, for all-PSCs. The two PSMAs show similar absorption edges, while PBDT shows a slightly higher lowest unoccupied molecular orbital (LUMO) energy level than PIDT. Benefitted from the relatively high LUMO levels of the two polymer acceptors, notable open-circuit voltage (Voc ) values over 1.0V are achieved when using them as acceptor to blend with PTQ10 as polymer donor. Particularly, the all-PSC based on PTQ10:PIDT demonstrates a power conversion efficiency of 10.19%, with an outstanding Voc of 1.10V benefitted from the higher LUMO energy level of PIDT acceptor. The results demonstrate a feasible strategy to design PSMAs by selecting appropriate linking units for increasing the Voc and improving the efficiency of all-PSCs.

Improvement in power conversion efficiency of all-polymer solar cells enabled by ultrafast channels for charge dynamics

Despite the rapid breakthrough of polymerized fused-ring small molecular acceptors, developing accessible and inexpensive polymer acceptors for high performance all-polymer solar cells (all-PSCs) and revealing the fundamental work mechanism of all-PSCs is highly desirable. In addition, the isomeric issue of polymerized fused-ring small molecular acceptors still needs to be concerned. In this work, we report an accessible and inexpensive polymer acceptor P2TF by polymerization of 2,2'-((2Z,2Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b']dith-iophene-2,7-diyl)bis (me-thanylylidene))bis (3-oxo-2,3-dihydro-1H-indene-2,1-diylide-ne)) dimalononitrile-based small molecular. Molecular electrostatic potentials and permanent dipole moments are evaluated by theoretical calculations, revealing that structural isomerization has a negligible impact on their optoelectronic properties. Femtosecond-resolved transient absorption, device charge dynamic measurements and space-charge limited current method are performed to systematically investigate charge dynamics in all-PSCs. The PM6:P2TF-based as-cast device exhibits poor power conversion efficiency of 4.51%, while the optimized device achieves a superior power conversion efficiency of 10.65%. The significantly improved performance of the optimized device originates from ultrafast channels of charge dynamics for ultrafast charge transfer, efficient charge transport and suppressed charge recombination, which is strongly related to the well-established morphology induced by optimal treatment. Furthermore, the PM6:P2TF also has excellent bending property, indicating its great potential for application in flexible all-PSCs.

Active Layer Morphology Engineering of All-polymer Solar Cells by Systematically Tuning Molecular Weights of Polymer Donors/Acceptors

In all-polymer solar cells (APSCs), number-average molecular weights (Mn) of polymer donors and polymer acceptors play an important role in active layer morphology and photovoltaic performance. In this manuscript, based on a series of APSCs with power conversion efficiency of approaching 10%, we study the effect of Mn of both polymer donor and polymer acceptor on active layer morphology and photovoltaic performance of APSCs. We select poly[4-(5-(4,8-bis(5-((2-butyloctyl)thio)thiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b']dithiophen-2-yl)thiophen-2-yl)-5,6-difluoro-2-(2-hexyldecyl)-7-(5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole] (CD1) as the polymer donor and poly[4-(5-(5,10-bis(2-dodecylhexadecyl)-4,4,9,9-tetrafluuoro-7-methyl-4,5,9,10-tetrahydro3a,5,8,10-tetraaza-4,9-diborapyren-2-yl)thiophen-2-yl)-7-(5-methylthiophen-2-yl)benzo[c][1,2,5]thiadiazole] (PBN-14) as the polymer acceptor. The Mn of polymer donor CD1 are 14.0, 35.5 and 56.1 kg mol-1, respectively. The Mn of polymer acceptor PBN-14 are 32.7, 72.4 and 103.4 kg mol-1, respectively. To get the desired biscontinueous fibrous network morphololgy of the polymer donor/polymer acceptor blends, at least one polymer should have high or medium Mn. Moreover, when the Mn of polymer acceptor is high, the active layer morphology and APSC device performance are insensitive to the Mn of polymer donor. The optimal APSC device performance is obtained when the Mn of both the polymer donor and the polymer acceptor are medium. These results provide a comprehensive and deep understanding on the interplay and the effect of Mn of polymer donors and polymer acceptors in high-performance APSCs.

High-performance all-polymer solar cells enabled by a novel low bandgap non-fully conjugated polymer acceptor

High-performance all-polymer solar cells enabled by a novel low bandgap non-fully conjugated polymer acceptor

High-Performance All-Polymer Solar Cells and Photodetectors Enabled by a High-Mobility n-Type Polymer and Optimized Bulk-Heterojunction Morphology

High-Performance All-Polymer Solar Cells and Photodetectors Enabled by a High-Mobility n-Type Polymer and Optimized Bulk-Heterojunction Morphology

Regulation of the Miscibility of the Active Layer by Random Terpolymer Acceptors to Realize High-Performance All-Polymer Solar Cells

The main limitations on the power conversion efficiency (PCE) of all-polymer solar cells (all-PSCs) are the weak absorption coefficients of widely used naphthalene diimide (NDI)-based polymer accep...

Thiophene-Fused Perylenediimide-Based Polymer Acceptors for High-Performance All-Polymer Solar Cells

Over the past years, perylenediimide (PDI)-based polymers have emerged as one of the widely studied polymer acceptors applicable to all-polymer solar cells (PSCs) due to their outstanding photovolt...

Highly Efficient and Stable All-Polymer Solar Cells Enabled by Near-Infrared Isomerized Polymer Acceptors

One of the most promising approaches to achieving high-performance all-polymer solar cells (all-PSCs) is to develop near-infrared polymer acceptors (PAs) constructed from n-type fused-ring electron...

Polymer Donors with Temperature-Insensitive, Strong Aggregation Properties Enabling Additive-Free, Processing Temperature-Tolerant High-Performance All-Polymer Solar Cells

In this work, the impact of temperature-dependent aggregation behaviors in benzodithiophene (BDT)-based polymer donors (PDs) on the electrical, morphological, and photovoltaic performances of all-p...

Terpolymer acceptors based on bithiophene imide for all-polymer solar cells

In order to improve light absorption and promote n-type performance, random copolymerization strategy was employed to afford a series of random terpolymer acceptors with acceptor1-acceptor2-acceptor3 (A1-A2-A3) type backbone. The polymers were synthesized from distannylated electron-deficient bithiophene imide monomer with various electron-deficient dibrominated co-monomers using the typical palladium-catalyzed Stille coupling condensation polymerization. Compared with their parent polymers, these A1-A2-A3 type terpolymer acceptors, particularly the dihexylthieno[3,4-b]pyrazine based terpolymer PBTP, can exhibit good miscibility, appropriate polymer crystallinity, and improved absorption in the long-wavelength region due to the incorporation of a third strong electron-withdrawing acceptor moiety thieno[3,4-b]pyrazine. Benefitting from the noncovalent S⋯N interactions, PBTP possessed a planar skeleton and achieved the highest power conversion efficiency (PCE) of 7.35% in the polymer series when serving as the acceptor material in all-polymer solar cells. These results indicate that the A1-A2-A3 type terpolymer acceptors should be promising candidates for developing high-performance all-polymer solar cells.

B ← N Bridged Polymer Acceptors with 900 nm Absorption Edges Enabling High-Performance All-Polymer Solar Cells

Most of the high-performance polymer acceptors have a defect of unsatisfying light-harvesting ability, e.g., a moderate absorption coefficient in films (Amax < 1 × 105 cm–1) or limited spectra cove...

Comparative Study of Selenophene- and Thiophene-Containing n-Type Semiconducting Polymers for High Performance All-Polymer Solar Cells

Effects of the donor moiety substitution on the intrinsic and photovoltaic blend properties of n-type semiconducting naphthalene diimide-arylene copolymers with donor–acceptor structure were invest...