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Dion-Jacobson (DJ) perovskites are promising alternatives for Ruddlesden-Popper (RP) perovskites to fabricate blue perovskite light-emitting diodes (PeLEDs) due to their favorable structural and charge properties. However, the relatively weak hydrogen bond between the bridging diammonium group and perovskite poses huge challenges for regulating crystallization and defect density, leading to an undesirable film quality and device performance. Herein, we report the successful optimization of DJ perovskite films by introducing a new type of cesium octafluoroadipate (CsOFAA) precursor, which could strongly anchor the perovskite through coordination bonds and halogen-halogen bonds. Such an interaction between CsOFAA and perovskite significantly stabilizes the DJ perovskite structure and suppresses the nonradiative recombination, leading to high-performance DJ perovskite films with efficient and stable blue emission. Accordingly, high external quantum efficiency values of 15.2%, 10.0%, and 8.3% are achieved for PeLEDs with emission peaks at 490, 485, and 479 nm, respectively, representing the most efficient blue DJ PeLEDs.

In this report, 38 nm-thick amorphous zinc-tin oxide (a-ZTO) films were deposited by radio frequency magnetron cosputtering. a-ZTO films were annealed by in situ monitoring of the sheet resistance improvements during the annealing process. A sharp drop in the slope of the sheet resistance curve was observed. The activation energies for the sheet resistance slope were calculated. The activation energy of the reaction for a sharp drop in the slope is much higher than the activation energy for the rest of the slope. Based on the activation energy values, six annealing temperatures were selected to saturate the highest conductivity at lower annealing temperatures and to identify the effects associated with annealing time. We found a direct correlation between annealing temperatures and the duration of the annealing treatment. a-ZTO films with a high conductivity of 320 S/cm were achieved by annealing at a temperature of 220 °C. It is noteworthy that the annealing temperature of 220 °C has clearly replaced the temperature of 300 °C. An irreversible decrease in resistivity was observed for all films. The conduction mechanism of films before and after annealing was determined. We confirm that all films individually exhibit semiconducting and metallic behaviors in the conduction mechanism before and after the lowest resistivity saturation., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)