Tethered Small‐Molecule Acceptors Simultaneously Enhance the Efficiency and Stability of Polymer Solar Cells

Abstract

For polymer solar cells (PSCs), the mixture of polymer donors and small‐molecule acceptors (SMAs) is fine‐tuned to realize a favorable kinetically trapped morphology and thus a commercially viable device efficiency. However, the thermodynamic relaxation of the mixed domains within the blend raises concerns related to the long‐term operational stability of the devices, especially in the record‐holding Y‐series SMAs. Here, a new class of dimeric Y6‐based SMAs tethered with differential flexible spacers is reported to regulate their aggregation and relaxation behavior. In their polymer blends with PM6, it is found that they favor an improved structural order relative to that of Y6 counterpart. Most importantly, the tethered SMAs show large glass transition temperatures to suppress the thermodynamic relaxation in mixed domains. For the high‐performing dimeric blend, an unprecedented open circuit voltage of 0.87 V is realized with a conversion efficiency of 17.85%, while those of regular Y6‐base devices only reach 0.84 V and 16.93%, respectively. Most importantly, the dimer‐based device possesses substantially reduced burn‐in efficiency loss, retaining more than 80% of the initial efficiency after operating at the maximum power point under continuous illumination for 700 h. The tethering approach provides a new direction to develop PSCs with high efficiency and excellent operating stability.

Oligomeric Acceptor Enables High‐Performance and Robust All‐Polymer Solar Cells with 17.4% Efficiency

“…[42] However, the oligomeric acceptors have not been considered to introduce in all-PSCs systems so far. [40,[50][51][52][53] Based on this point, it is urgent and significative to study the influence of an oligomeric acceptor as the third component on the performance and mechanical robustness in all-PSCs systems.…”

“…[42] However, the oligomeric acceptors have not been considered to introduce in all-PSCs systems so far. [40,[50][51][52][53] Based on this point, it is urgent and significative to study the influence of an oligomeric acceptor as the third component on the performance and mechanical robustness in all-PSCs systems.With these in mind, we designed and synthesized a polymer acceptor (named PZC24) through linking CH-series SMA [54][55][56] by the fluoro-substituted thiophene π bridge. By blending PZC24 with the polymer donor PM6, a decent PCE of 16.82% is achieved.…”

Molecular Packing and Dielectric Property Optimization through Peripheral Halogen Swapping Enables Binary Organic Solar Cells with an Efficiency of 18.77%

“…Organic solar cell (OSC) has been regarded as one of the most attractive technologies for renewable energy applications, due to its complementary advantages to silicon solar cells in solution processing, low cost, light-weight, flexibility, semitransparency, etc. [1][2][3][4][5][6][7] Recently, over 19% power conversion efficiencies (PCEs) of OSCs have been achieved, [8][9][10][11][12][13][14][15][16][17] narrowing the PCE gap with other inorganic solar cells greatly. These encouraging advances of OSCs are mainly caused by the rapid development of non-fullerene acceptors (NFAs), which have caused the overall improvements of three tangling photovoltaic potentials for improving dielectric properties to further evaluate the FF and J SC of OSCs have been attached by the remarkable structural diversity of organic molecules.…”

Dredging photocarrier trapping pathways via “charge bridge” driven exciton–phonon decoupling enables efficient and photothermal stable quaternary organic solar cells

“…[12][13][14] Depending on the degraded microstructure, singlet excitons in nanoscale spatial region might control light emission and undergo a large number of non-radiative processes, such as diffusion, annihilation, localization into trap states, and dissociation into charge carriers. Quite recently, some feasible strategies such as constructing a multiple-component photoactive layer based on onepot polymerization, 15 combining NFAs with a similar structure yet different morphological features, 16 designing oligomer molecules and polymer acceptors, [17][18][19] and employing solid additives 20,21 have been proposed to overcome this conundrum related to the metastable morphology. The recent progress made in revealing the degradation mechanism and improving the device lifetime of the state-of-the-art OSCs under various aging conditions is summarized in Table S1 (ESI †).…”