Vertical Stratification Engineering of Insulating Poly(aryl ether)s Enables 18.6% Organic Solar Cells with Improved Stability

Abstract

Control of the preferred vertical phase distribution of the components in the photoactive layer is of vital importance to improve the device performance and stability of organic photovoltaics (OPVs). Herein, a universal sequential-deposition strategy is demonstrated to realize optimal vertical phase distribution by employing orthogonal solvents and synergistically integrating ternary/quaternary compositions consisting of insulating heat-resistant poly­(aryl ether)­s as the third/fourth component in a photoactive layer. The selective segregation of poly­(aryl ether)­s in the middle of the active layer enhances molecular packing of the photovoltaic materials and improves the charge transport and extraction properties. A maximum efficiency of 18.6% is achieved for PM6:BTP-eC9:PC71BM:poly­(aryl ether)-based quaternary solar cells, with photo/thermal stability that is better than that of devices without poly­(aryl ether). This work provides an effective approach for achieving stable and efficient OPVs with expected topology by tuning molecular packing behaviors and the vertical segregation of multicomponents in photovoltaic layers.

n-Type polymer electron acceptors for organic solar cells

“…OSCs have attracted considerable interest from both the industrial and academic communities due to their advantages such as compatibility with flexible substrates, potentially low-cost manufacturing and easy processability over a large area via roll-to-roll or printing technologies. [1][2][3][4][5] They have quickly become a research hotspot and achieved rapid development. After decades of development, the performance of OSCs has greatly improved, and their power conversion efficiency (PCE) has exceeded 19%.…”

“…BDT units have been widely used in the design of donor materials due to their large conjugate planes and excellent charge transport properties. 2,3 Lee and co-workers 123 designed and synthesized a the small molecule BDT2TR (Fig. 8f) with bi-BDT as the core, thiophene as the π bridge and ethyl rhodanine as the terminal group.…”

Formation of Efficient Quasi-All-Polymer Solar Cells by Synergistic Effect of the Ternary Strategy and Solid Additives

“…However, the introduction of small molecules may affect the mechanical properties of the solar cells. In our previous work, − poly­(aryl ether) materials with a high dielectric constant can build up finely mixed matrices in active layers, which not only significantly improved the stability and flexibility but also improved the photovoltaic performance of the device. Therefore, it is meaningful to combine the ternary strategy and additive engineering to jointly control the appearance and the interactions among the molecules of the blends.…”

Challenging PM6-like donor polymers for pairing with a Y-type state-of-the-art acceptor in binary blends for bulk heterojunction solar cells

“…Despite their record breaking PCE values, the non-ideal V OC of below 0.84 V still reflects the imperfect molecular design of PM6 or similar backbone structures for ideal control of their HOMO/LUMO levels. 7,9,[11][12][13][14][15][16][17][18] As is well known, the absorption bands, carrier mobility, crystallization, and morphology of bulk-heterojunction layers are closely related to the short circuit current ( J SC ), while the energy level difference between the HOMO of the donor and the LUMO of the acceptor corresponds to the open circuit voltage (V OC ). Both J SC and V OC are vital parameters that affect the PCE of OSCs.…”