Hot-injection synthesis of lead-free pseudo-alkali metal-based perovskite (TlSnX3) nanoparticles with tunable optical properties

The commercialization of organo-inorganic hybrid perovskite materials for optoelectronic applications is limited owing to the restriction of lead (Pb) usage in consumer electronics and the instability of organic cations in the perovskite structure. To address these challenges, we synthesize TlSnX 3 (X = Cl, Br, and I) perovskite nanoparticles (NPs) with high crystallinity and uniformity using the hot-injection method. The optical properties of TlSnX 3 NPs are fine-tuned by substituting the halide ions of TlSnX 3 . In addition, the oxidation of Sn in TlSnX 3 NPs is effectively prevented by the strong reducing ligands such as dioleamide (DOA) and trioctylphosphine (TOP). Furthermore, TlSnX 3 NPs-based perovskite solar cells (PSCs) are fabricated by a spin-coating method; they exhibited a high open-circuit voltage (∼1.4 V). These results demonstrate that TlSnX 3 NPs can be an attractive candidate for solution-processable optoelectronic devices.