Ferroelectric Polymer Drives Performance Enhancement of Non‐fullerene Organic Solar Cells

Abstract

Enhancing the built-in electric field to promote charge dynamitic process is of great significance to boost the performance of the non-fullerene organic solar cells (OSCs), which has rarely been concerned. In this work, we introduced a cheap ferroelectric polymer as an additive into the active layers of non-fullerene OSCs to improve the device performance. An additional and permanent electrical field was produced by the polarization of the ferroelectric dipoles, which can substantially enhance the built-in electric field. The promoted exciton separation, significantly accelerated charge transport, reduced the charge recombination, as well as the optimized film morphology were observed in the device, leading to a significantly improved performance of the PVDF-modified OSCs with various active layers, such as PM6 : Y6, PM6 : BTP-eC9, PM6 : IT-4F and PTB7-Th : Y6. Especially, a record efficiency of 17.72 % for PM6 : Y6-based OSC and an outstanding efficiency of 18.17 % for PM6 : BTP-eC9-based OSC were achieved.

Controlling Morphology and Voltage Loss with Ternary Strategy Triggers Efficient All-Small-Molecule Organic Solar Cells

“…The innovation of organic photovoltaic materials has always been the most visible and effective method to break through the bottleneck of efficiency in the development history of OSCs. − Employing advisible optimization strategies to unlock the full potential of donors and acceptors is a necessary process for realizing efficient OSCs. The traditional optimization techniques, such as solvent/solid additives and solvent-vapor/thermal annealing, have been well demonstrated to be effective approaches for enhancing charge generation and extraction by regulating the molecular distribution and arrangement, while they are powerless to reduce the voltage loss of the OSCs. − The ternary strategy can gather multiple superiorities in one matrix via incorporating a complementary third component with the binary host system, which is also easy to combine with traditional optimization techniques due to the retentive single-junction device structure. − Introducing the third component with suitable energy levels and bandgap possesses the potential to decrease voltage loss of OSCs. Moreover, the appropriate compatibility can provide the possibility to modulate film morphology and then promote charge production and transport, which has already been certified in various types of OSCs. − Considering the above analyses, the ternary tactic could be a potential thoroughfare to simultaneously control the sensitive morphology and voltage loss for realizing efficient ASM-OSCs.…”

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

“…As shown in Figures B and S4, the dipole moment of PAEN is 16.49 D, which is much greater than those of PM6 (1.78 D) and Y6 (1.25 D). Generally, a high dipole moment can enhance the dielectric properties of the materials, which could decrease charge recombination and the exciton binding energy by the surrounding dielectric environment. − Herein, the dielectric constant (ε r ) at 1 MHz for PAEN is 4.5, which is greater than the one (ε r ≈ 2) for the polymer donor PM6 . Although addition of PAEN into the high-performance PPHJ blends, containing Y6 with remarkable small exciton binding energies, did not show significantly improved charge generation and decay dynamics in the TA spectra, such high dipoles and surrounding high dielectric environment could also be beneficial for the high photovoltaic performance.…”

Carboxylate-Containing Wide-Bandgap Polymers for High-Voltage Non-Fullerene Organic Solar Cells

“…Organic solar cells (OSCs), as one of the new renewable energy technology, have received widespread attention due to their low cost, lightweight, band gap tunability, and excellent solution processability. , Based on the abovementioned points, OSCs not only have great application prospects in outdoor photovoltaics but can also shine in indoor photovoltaics. Throughout their development, photovoltaic material design is an indispensable part. − To increase the market competitiveness in traditional outdoor applications, continuous research has focused on tailoring the organic photovoltaic materials to show matched absorption with the solar spectrum. Due to the late start of indoor photovoltaics, the corresponding material design is still insufficient.…”