Non-Fullerene Acceptor In High-Efficiency OPV Cells

What Is Non-Fullerene Acceptor?

A non-fullerene acceptor is an electron-accepting organic semiconductor designed to replace fullerene derivatives in bulk heterojunction solar cells. Unlike spherical fullerenes, these molecules can be built with strong light absorption, tunable energy levels, and shapes that promote more favorable molecular packing in thin films.

In organic bulk heterojunction design, the acceptor receives electrons at the donor-acceptor interface and helps create continuous transport pathways to the cathode. Compared with PCBM, many non-fullerene systems also absorb visible and near-infrared light, so both halves of the blend contribute meaningfully to photocurrent.

A common design parameter is Delta E = E_acceptor – E_donor at the interface, which influences charge transfer and open-circuit voltage. Why it matters is that better acceptors can raise current, preserve voltage, and limit nonradiative energy losses that older fullerene blends accepted as unavoidable.

Used in devices include organic solar cells, semitransparent solar windows, and flexible charging films. Researchers tune side chains, molecular symmetry, and packing behavior because nanoscale morphology stability often decides whether high lab efficiency survives long-term operation, repeated illumination, thermal cycling, long outdoor exposure, and practical weathering conditions.

Example:
A PM6:Y6 blend reaches higher photocurrent than an older polymer:fullerene blend because the acceptor absorbs more sunlight directly.

Related Concepts:

• PCBM
• Conjugated Polymer
• Power Conversion Efficiency