How Deep Hole Traps Affect the Charge Dynamics and Collection in Bare and Bilayers of Methylammonium Lead Bromide

• DOI: 10.1021/acsami.1c00714
• Publication Date: 2021-03-31T14:14:49Z
• Authors: Jiashang Zhao; Valentina M. Caselli; Marcel Bus; Bart Boshuizen; Tom J. Savenije
• Keywords: Tandem; Charge carrier

Wide-band-gap perovskites such as methylammonium lead bromide (MAPB) are promising materials for tandem solar cells because of their potentially high open-circuit voltage, which is yet still far below the maximum limit. The relatively short charge-carrier lifetimes deduced from time-resolved photoluminescence (TRPL) measurements seem in strong contrast with long observed photoconductance measurements. This explained by a large amount hole defect states, NT > 1016 cm–3, spin-coated layers MAPB residing at or near grain boundaries. introduction hypophosphorous acid (HPA) increases average size factor 3 and reduces total concentration trap states 10. HPA also fraction initially generated holes that undergo charge transfer to selective contact, Spiro-OMeTAD (SO), an order magnitude. In iodide (MAPI)/SO bilayers, reduction carrier lifetime MAPB/SO attributed fact injected interfacial recombination via these states. Our findings provide valuable insight into optoelectronic properties bromide-containing halide essential designing efficient cells.