Carbon quantum dot additive engineering for efficient and stable carbon-based perovskite solar cells

Additive engineering is an effective method to manipulate formation of methyl ammonium metal halide perovskite film for high performance perovskite solar cells (PSCs). In this work, carbon quantum dots (CQDs) prepared from two different carbon sources named as A-CQD and CA-CQD respectively are applied as additives into CH₃NH₃PbI₃ precursor solution via one-step processing. Film morphology and charge transport dynamics of perovskite films with different CQDs additives are investigated. It is found that the A-CQDs incorporated perovskite film has large grain size, excellent crystallinity, enhanced carrier transport ability and high hydrophobic surface. Carbon-based perovskite solar cell using the A-CQD additive shows increased cell performance with the maximum power conversion efficiency (PCE) of 13.28%. While, PCE of the PSCs modified by the CA-CQD additive and without additive are 7.85% and 10.50% respectively. The A-CQD additive modified PSC also presents good long-term stability and maintains more than 90% of its initial PCE after 200 h.