Ternary Organic Solar Cells with Binary Additives Finely Regulated Active Layer Morphology and Improved Photovoltaic Performance

Abstract

Solvent additive can be used to regulate active layer morphology and improve photovoltaic performance of organic solar cells (OSCs). Herein, the PM6:Y6:PC71BM ternary bulk heterojunction OSCs are prepared by introducing 1,8‐diiodooctane (DIO) and 1‐chloronaphthalene (CN) as binary additives. On the basis of optimizing the photovoltaic performance with CN additive, the addition of trace amounts of DIO additive further improves the molecular packing of active layer and induces Y6:PC71BM acceptor on the surface of active layer. With the optimized active layer morphology, the CN and DIO binary additives restrict carrier recombination and improve charge transport efficiently, and the prepared PM6:Y6:PC71BM ternary OSCs with binary additives demonstrate a high short‐circuit current density of 27.15 mA cm−2 and a fill factor of 76.79%, and yield an improved power conversion efficiency of 17.53%, which is higher than that of devices without additives (16.50%) and with DIO (16.79%) or CN additive (17.21%). Binary solvent additives engineering provides an effective strategy to finely regulate active morphology and boost photovoltaic performance of ternary OSCs.

Additive-assisted strategy for high-efficiency organic solar cells

“…With the expectation of compromising the effect of the two kinds of additives, binary additives have been investigated in the past few years. 124–129 For instance, He and Zhao et al reported the OSC based on FTAZ:IDCIC (Fig. 2) with the binary additive, 1-CN&DIO, afforded a decent PCE of 13.58%, much higher than the counterparts with no additive (9.64%), DIO (9.76%), and CN (11.81%), respectively.…”

Highly Efficient Nonfullerene Organic Solar Cells: Morphology Control and Characterizations

“…TEM that has a very high resolution <1 nm is a powerful electron microscopy-based technique, which is capable of yielding phase images and providing detailed phase morphological analysis with the help of energy-dispersive X-ray spectroscopy or electron energy-loss spectroscopy (EELS). [30,31] However, traditional bright-field TEM often fails to yield a highly contrasted phase image because of similar mass/electron densities of polymer donors and NFAs. Several electron microscopy-coupled techniques have thus been developed to generate enhanced image contrast for phase identification based on the electronic structure of materials in blend films.…”