摘要
An additive 2,5-Dibromo-3,4-pyridinediamine (DBPDA) is used to passivate the defects and mitigate the micro-strain in mixed Sn-Pb perovskite based solar cells and thin film transistors. The DBPDA incorporated perovskite solar cell achieves a remarkable power conversion efficiency of 21.24%, while the thin film transistor shows an significantly enhanced hole mobility of 1.43 cm2/V-s.
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•Employed 2,5-Dibromo-3,4-pyridinediamine (DBPDA) for bulk defect passivation in mixed Sn-Pb perovskite solar cells to enhance performance and stability.•The addition of DBPDA into perovskite minimizes micro-strain and prevents Sn2+ oxidation through interactions with its pyridine nitrogen, amine groups, and bromine atoms.•DBPDA incorporated PSCs achieved a PCE of 21.24 %, Voc of 0.85 V, FF over 81 %, with 1,008 h of long-term stability and 240 h of thermal stability.•Moreover, mixed Sn-Pb perovskite-based thin-film transistors (TFTs) exhibit a notable increase in hole mobility, achieving 1.43 cm2/V·s with the addition of DBPDA.
Mixed Tin-lead (Sn-Pb) perovskite solar cells (PSCs) offer a promising avenue for achieving high power conversion efficiencies (PCEs) due to their narrow bandgaps and substantial optical absorption in the visible–near-infrared region. However, the disparated reaction kinetics of PbI2 and SnI2 with organic salts, resulting in an uneven spatial distribution of Sn2+ and Pb2+ within the perovskite lattice, inducing micro-strain in the film and a Sn-rich surface vulnerable to oxidation-Sn2+ to Sn4+, thereby elevating nonradiative recombination. Here, we report the incorporation of 2,5-Dibromo-3,4-pyridinediamine (DBPDA) as an additive in the mixed Sn-Pb perovskite precursor solution, designed to mitigate micro-strain formation, reduce defect density by suppressing Sn4+ formation, and enhance the passivation of undercoordinated Sn/Pb species through synergistic bonding interaction. The best performing PSCs achieved an impressive PCE of 21.24 % with a high open circuit voltage (Voc) of 0.85 V, alongside significantly improved long-term stability, retaining near 80 % of their initial PCE after 1,008 h in a nitrogen-filled glovebox without encapsulation. In contrast, the control devices retained only 18 % of their initial efficiency under identical conditions. Additionally, an enhanced field effect hole mobility, increasing from 0.18 cm2/V-s in the control film to 1.43 cm2/V-s in the target film, was achieved in mixed Sn-Pb perovskite thin film transistors (TFTs) using these films as active layers. These findings present a viable strategy for strain-relieved perovskite films, enabling stable and high-performance mixed Sn-Pb PSCs and TFTs.