{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"7b6d55c9b256466aae4d99c6b438ac1e9f9205fadb00c830f082e2a3ac68665d","created":"2026-10-03T07:17:59Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"8a3d7fa2ea4e9e8149393fa808a3dce303151374edd58106c90b2168009cc978","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"cm.halide-perovskites.halide-segregation","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Under light, mixed iodide-bromide perovskites un-mix into iodine-rich and bromine-rich patches, which lowers solar-cell voltage; in the dark they mix again. The driving force is debated.","posed_since":"2015","precise":"In MAPb(I_xBr_1-x)3 with Br fraction above about 0.2, illumination produces I-rich domains emitting near 1.68 eV within minutes, reversibly in the dark (Hoke et al. 2015). Determine the driving force (free-energy lowering from carriers collecting in low-gap I-rich regions, polaron-induced strain, or field gradients from trapped charge) and predict the threshold intensity and steady-state composition versus intensity and temperature. An answer is a mechanism with a quantitative steady-state phase diagram.","problem_ref":null,"references":"","settled_by":"Intensity- and temperature-resolved steady-state composition maps that match one model's predicted threshold and phase diagram while excluding the others.","status_note":"","title":"Mechanism of light-induced halide segregation in mixed-halide perovskites","topic_ref":"56bceea3ae46655d4fa657e5e962c04f828a636d2ee81dabedfcad2bf6f6582c"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"360286afdc3d99e7c65a76b6ede4f133f02ad29e44f88fbc5af9c88c3c92bf48","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"fb1c46f4c91ef738c911f73cdc10aa9669c6570b6a48d13cbb2ebfa02b82101e","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"HSdkZ4jTYl2nqTftfA9MYWrl_-cNX9w9_zm38KSAfF1E9RAF1KxDOIEk07UNuIQFKYyHy7kw808Qw2EXooMCAA"},"schema":"pubphys.envelope/1"},"record_hash":"360286afdc3d99e7c65a76b6ede4f133f02ad29e44f88fbc5af9c88c3c92bf48","leaf_index":1004}