A high-efficiency organic solar cell based on fluorinated electron donor and fluorinated electron acceptor

Abstract

The invention discloses a high-efficiency organic solar cell based on a fluorinated electron donor and a fluorinated electron acceptor, which comprises a substrate, a cathode, a cathode modification layer, an active layer, an anode modification layer and an anode, wherein the active layer is a fluorinated Blend film of electron donor PBDB‑TF and fluorinated electron acceptor HF‑PCIC. Utilize the widened absorption range and high electron mobility of HF-PCIC, and select the fluorinated electron donor PBDB-TF with good energy level matching and compatibility with HF-PCIC, the organic solar cell prepared by the present invention maintains high At the same time of open circuit voltage and fill factor, short circuit current density increased to 17.81mA / cm 2 , the highest power conversion efficiency (PCE) is 11.49%, which is significantly better than organic solar cells (PCE=10.14%) using unfluorinated electron donors and unfluorinated electron acceptors. In addition, HF‑PCIC is easy to synthesize, which is beneficial to reduce the cost of organic solar cells.

Description

technical field [0001] The invention relates to a solar cell, in particular to a high-efficiency organic solar cell based on a fluorinated electron donor and a fluorinated electron acceptor. Background technique [0002] In recent years, organic solar cells based on non-fullerene electron acceptors have made important progress, and the power conversion efficiency (PCE) of the cells has exceeded 13% (Journal of the American Chemical Society, 2017, 139, 7148), which is higher than that of the same industry. Efficiency values ​​for type fullerene cells. In order to further improve the efficiency of non-fullerene batteries, the light absorption range of non-fullerene electron acceptors should be extended to the near-infrared region, and the electron mobility should also be improved, so that the batteries can obtain greater short-circuit current density. [0003] Fluorinating the electron-withdrawing terminal groups of non-fullerene electron acceptors is an effective method to i...

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned fluorinated non-fullerene electron acceptors all have an aromatic condensed ring central unit, which is difficult to synthesize and high in cost, which is not conducive to the popularization and application of organic solar cells.

For this reason, Chinese patent 201710409496.1 discloses a non-fullerene electron acceptor DFPCIC with non-fused ring difluorobenzene as the central unit. The synthesis is simple, but its electron-withdrawing terminal group is unfluorinated cyanoindanone , the ICT effect is not strong enough, the absorption band edge is only 781nm, and the electron mobility is also small, 2.6×10 -5 cm 2 V - 1 the s -1

Therefore, the organic solar cell with DFPCIC as the electron acceptor has a PCE of 10.14%, and a short-circuit current density of only 15.66mA / cm 2 , to be further improved

[0005] In addition, the fluorination will reduce the energy level of the non-fullerene electron acceptor. If the energy level of the electron donor blended with it is not adjusted accordingly, it will inevitably cause a decrease in the open circuit voltage of the battery; there is another consideration The problem is that the fluorination strengthens the intermolecular interactions of the non-fullerene electron acceptors, which inevitably leads to a change in the morphology of the active layer, which has an important impact on the fill factor of the battery.

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