Rational control of sequential morphology evolution and vertical distribution toward 17.18% efficiency all-small-molecule organic solar cells

All-small-molecule organic solar cell (ASM OSC) with an efficiency of up to 17.18% is demonstrated via combining layer-by-layer (LbL) deposition and solid additive methoxy-substituted graphdiyne (GOMe) treatment to manipulate active layer morphology. The rationally controlled morphology with ordered molecular stacking and vertical distribution has dual advantages, as the solid additive GOMe is a good molecular stacking regulator, and LbL configuration serves as a vertical charge-transporting highway with sufficient donor/acceptor interfaces, benefiting carrier generation and transport enhancement simultaneously. A remarkable fill factor of = 77.31% is recorded, and an efficiency of 17.18% is the highest power conversion efficiency (PCE) for ASM OSCs reported to date.

Automated summary

A highly efficient all-small-molecule organic solar cell with a power conversion efficiency of 17.18% is demonstrated through layer-by-layer deposition and solid additive treatment. The controlled morphology allows for ordered molecular stacking and vertical charge transport, resulting in enhanced carrier generation and transport.