Post-synthetic halide conversion and selective halogen capture in hybrid perovskites

• Published in: Chemical science (Cambridge) Vol. 6; no. 7; pp. 4054 - 4059
• Main Authors: Solis-Ibarra, D, Smith, I C, Karunadasa, H I
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01.01.2015
• Subjects: Chemistry; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c5sc01135c

Reaction with halogen vapor allows us to post-synthetically exchange halides in both three- (3D) and two-dimensional (2D) organic-inorganic metal-halide perovskites. Films of 3D Pb-I perovskites cleanly convert to films of Pb-Br or Pb-Cl perovskites upon exposure to Br or Cl gas, respectively. This gas-solid reaction provides a simple method to produce the high-quality Pb-Br or Pb-Cl perovskite films required for optoelectronic applications. Reactivity with halogens can be extended to the organic layers in 2D metal-halide perovskites. Here, terminal alkene groups placed between the inorganic layers can capture Br gas through chemisorption to form dibromoalkanes. This reaction's selectivity for Br over I allows us to scrub Br to obtain high-purity I gas streams. We also observe unusual halogen transfer between the inorganic and organic layers within a single perovskite structure. Remarkably, the perovskite's crystallinity is retained during these massive structural rearrangements.