Trap passivation and efficiency improvement of perovskite solar cells by a guanidinium additive

A photoactive layer with efficient charge transport and low charge recombination is critical to prepare perovskite solar cells with high efficiency and superior stability. We demonstrate that the incorporation of an effective additive 1,3-diaminoguanidine monohydrochloride (DAGCl) in the MAPbI3 film can increase the perovskite grain size and reduce trap density, consequently increasing the carrier lifetime and reducing charge recombination. This leads to an improvement in maximum power conversion efficiency from 19.1% to 20.3% as well as increased lifetime, with an inverted device structure of glass/ITO/PolyTPD/MAPbI3/PC61BM/ZrAcac/Ag.