Regulating the morphology of fluorinated non-fullerene acceptor and polymer donor via binary solvent mixture for high efficiency polymer solar cells

Abstract

This is a repository copy of Regulating the morphology of fluorinated non-fullerene acceptor and polymer donor via binary solvent mixture for high efficiency polymer solar cells.

Simultaneously Enhanced Efficiency and Operational Stability of Nonfullerene Organic Solar Cells via Solid‐Additive‐Mediated Aggregation Control

“…This rapid development is not only related to the emergence of new photovoltaic materials, but also inextricably tied to the optimization of molecular stacking and aggregation of organic semiconductors within the photoactive layer. [ 8–13 ] Nevertheless, the commercialization of OSCs not only depends on device PCE but also critically relies on their stability, [ 14 ] which is affected by the chemical structure and photosensitivity of the photoactive materials, photo‐oxidation, temperature‐induced phase transition, and degradation evoked at the electrode interface. [ 15–20 ]…”

Controlling solid-state structure and film morphology in non-fullerene organic photovoltaic devices

“…As polymer motion in the film is relatively slow, fast evaporation can kinetically trap the film in a non-equilibrium state. This means that low-boiling solvents spin-cast at high speeds 109 lead to a relatively intermixed active layer with a majority of L-L phase separation, while high boiling 110 solvents allow more time for S-L demixing and contribute to higher levels of phase separation in the film. 20 This was demonstrated by Chen et al 110 where chloroform led to small domains and chlorobenzene led to large domains, but a mixture of the two produced optimal domain sizes.…”

“…This means that low-boiling solvents spin-cast at high speeds 109 lead to a relatively intermixed active layer with a majority of L-L phase separation, while high boiling 110 solvents allow more time for S-L demixing and contribute to higher levels of phase separation in the film. 20 This was demonstrated by Chen et al 110 where chloroform led to small domains and chlorobenzene led to large domains, but a mixture of the two produced optimal domain sizes. Historically, chlorobenzene has been the solvent of choice as it has a relatively high boiling point (132 °C) and preferentially solubilizes most donor polymers, thereby encouraging the S-L demixing of the small-molecule acceptor.…”

Molecular optimization of incorporating pyran fused acceptor–donor–acceptor type acceptors enables over 15% efficiency in organic solar cells

“…Note that this is above their intrinsic merits of solution-processing, light weight, semi-transparency, flexibility and large-scale roll-to-roll production. 1–17 A typical OSC device usually employs an electron donor and acceptor blend as the light active layer, which plays a dominant role in the photovoltaic performance of OSCs. 18–31 Recently reported high-performance acceptor–donor–acceptor (A–D–A) type non-fullerene acceptors (NFAs) usually possess strong absorption in the near-infrared region and favorable molecular stacking, thereby generating a systematically enhanced photocurrent and voltage output.…”