High-Performance Intrinsically Stretchable Polymer Solar Cell with Record Efficiency and Stretchability Enabled by Thymine-Functionalized Terpolymer

Abstract

Designing new polymer semiconductors for intrinsically stretchable polymer solar cells (IS-PSCs) with high power conversion efficiency (PCE) and durability is critical for wearable electronics applications. Nearly all high-performance PSCs are constructed using fully conjugated polymer donors (P D ) and small-molecule acceptors (SMA). However, a successful molecular design of P D s for high-performance and mechanically durable IS-PSCs without sacrificing conjugation has not been realized. In this study, we design a novel thymine side chain terminated 6,7-difluoro-quinoxaline (Q-Thy) monomer and synthesize a series of fully conjugated P D s (PM7-Thy5, PM7-Thy10, PM7-Thy20) featuring Q-Thy. The Q-Thy units capable of inducing dimerizable hydrogen bonding enable strong intermolecular P D assembly and highly efficient and mechanically robust PSCs. The PM7-Thy10:SMA blend demonstrates a combination of high PCE (>17%) in rigid devices and excellent stretchability (crack-onset value >13.5%). More importantly, PM7-Thy10-based IS-PSCs show an unprecedented combination of PCE (13.7%) and ultrahigh mechanical durability (maintaining 80% of initial PCE after 43% strain), illustrating the promising potential for commercialization in wearable applications.

Polymer Acceptor with Hydrogen-Bonding Functionality for Efficient and Mechanically Robust Ternary Organic Solar Cells

“…However, 20 wt % of N2200-ThyDap led to a higher stretchability (COS = 5.5%) compared to 10 wt % of N2200-ThyDap (COS = 4.8%). These results demonstrate that the reversible and dynamic bonding within the blend film likely improved mechanical robustness, resulting in higher COS values. , …”

“…Thymine and diaminopyrazine functional groups were introduced to the N2200 polymer backbone to afford the H-bonding ability to the P A . N2200-ThyDap was synthesized by Stille polycondensation of 6-((5,8-dibromo-6,7-difluoroquinoxalin-2-yl)­oxy)­hexyl-2-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1­(2 H )-yl)­acetate (Q-Thy), the novel monomer 6-((2,6-dihexanamidopyrimidin-4-yl)­oxy)­hexyl-2,5-dibromothiophene-3-carboxylate (T-Dap), 4,9-dibromo-2,7-bis­(2-octyldodecyl)­benzo­[lmn]­[3,8]­phenanthroline-1,3,6,8­(2 H ,7 H )-tetraone (NDI), and 5,5′-bis­(trimethylstannyl)-2,2′-bithiophene. Detailed information about the synthesis of the novel T-Dap monomer and N2200-ThyDap is described in the Supporting Information.…”

“…For instance, Chen et al introduced only two thymine units into the chain ends of a polymer and found the toughness of the thymine-incorporated polymer (155.17 MPa) was 80 times higher than the reference polymer (1.9 MPa) . As a result, the enhanced stretchability of PM6:Y6-BO:N2200-ThyDap compared to the other blends is still attributed to the enhanced intermolecular interactions of N2200-ThyDap within the blend through the introduction of Thy and Dap functional groups. ,,, To support this hypothesis, we compared the stretchability of the 20 wt % P A incorporated films (Figure S15 and Table S6). Here, the 20 wt % N2200-incorporated ternary blend film showed a similar stretchability (COS = 2.5%) compared with the 10 wt % N2200-incorporated blend film (COS = 2.4%).…”

Regioisomeric Engineering of Dimerized Small-Molecule Acceptors for Efficient and Stable Organic Solar Cells

“…As a result, the μ h /μ e ratio was more balanced in PM6:DYSe-I (μ h /μ e = 2.3) than in PM6:DYSe-O (μ h /μ e = 4.0) (Table S4). Overall, the desirable charge generation, transport, and recombination properties of the PM6:DYSe-I blend accounted for the higher J sc and FF values than those of the PM6:DYSe-O blend …”

Pseudo-bilayered inverted organic solar cells using the Marangoni effect

“…To optimize the morphology of the BHJ structure, researchers have considered adding solvent additives, 9–13 heating, 14 solvent vapor annealing, 15–18 controlling the donor/acceptor (D/A) ratio, 19,20 adopting ternary components, 8,21–24 or implementing the side-chain modulation of materials. 25–28 Nevertheless, BHJ architectures require optimized donor and acceptor networks; otherwise, severe recombination may occur during exciton dissociation or charge transport. 29–33 Therefore, as an alternative to the BHJ architecture, bilayers or, in general, pseudo-bilayer (PB) architectures comprising vertical donor- and acceptor-rich layers along with a D/A mixed layer, have recently received increasing attention.…”