Six-angle polarized snowflake-like carbon quantum dots via electrostatic reversion for low-cost and high-efficiency solar cells

Abstract

Although organic solar cells (OSCs) have power conversion efficiencies (PCEs) exceeding 20%, high material cost of active layer hinders their practical applications. Carbon quantum dots (CQDs) with low cost, unique optoelectronic properties, and structural functionalization are promising candidates for solar cells (SCs). However, CQDs as active layers so far merely had 1% PCEs. Here, we report the one-step synthesis of snowflake-like CQDs with one carbon core and six equivalent polarized angles (Six-SL-CQDs), showing cost as low as ∼$18.07/g and adequate solution processability. Experimental results reveal that the designed structure can reverse the electrostatic potential generated between six angles and carbon core. Six-SL-CQDs serve as acceptor molecules to construct strong donor-acceptor intermolecular interactions, leading to orderly structural stacking and effective exciton dissociation. SCs exhibit a maximum PCE of 10.3% and long-term stability, with T₈₀ exceeding 2,078 h. These findings break the cost bottleneck and facilitate the practical application of carbon nanomaterial-based SCs.