Spontaneous Formation of Single-Crystalline Spherulites in a Chiral 2D Hybrid Perovskite

• DOI: 10.1021/jacs.4c15471
• Publication Date: 2025-01-21T13:27:11Z
• Authors: Shunran Li; Du Chen; Bowen Li; Hanfei Yan; Benjamin J. Lawrie; Bongjun Choi; Dongjoon Rhee; Yanyan Li; Huan Zhao; Linqi Chen; Ajith Pattammattel; Suchismita Sarker; Deep Jariwala; Peijun Guo
• Keywords: Spherulite (polymer physics); Supramolecular chirality; Chirality

In two-dimensional (2D) chiral metal-halide perovskites (MHPs), organic spacers induce structural chirality and chiroptical properties in the sublattice. This enables reversible crystalline-glass phase transitions (S-NEA)2PbBr4, a prototypical 2D MHP where NEA+ represents 1-(1-naphthyl)ethylammonium. Here, we investigate two distinct spherulite states of exhibiting either radial-like or stripe-like banded patterns depending on annealing conditions amorphous film. Despite similarities optical absorption photoluminescence, stripe-like, exhibits higher crystallinity improved transparency compared to those spherulite. X-ray nanoprobe measurements reveal tilting-angle modulations octahedral plane spherulites, correlating with film's surface geometry. Transfer matrix calculations indicate that contrast patterns, seen bright-field microscopy, arises from interference effects, differing mechanism observed polymer spherulites. Ultrafast carrier dynamics experiments suggest spherulites resemble single crystals more closely than while electrical conductivity show enhanced charge transport These findings offer insights into composition but different morphologies, previously only polymers, highlighting their potential for optoelectronic applications.