title: Methylammonium Bismuth Iodide as a Lead-Free, Stable Hybrid Organic-Inorganic Solar Absorber.
abstract: Methylammonium lead halide (MAPbX3 ) perovskites exhibit exceptional carrier transport properties. But their commercial deployment as solar absorbers is currently limited by their intrinsic instability in the presence of humidity and their lead content. Guided by our theoretical predictions, we explored the potential of methylammonium bismuth iodide (MBI) as a solar absorber through detailed materials characterization. We synthesized phase-pure MBI by solution and vapor processing. In contrast to MAPbX3, MBI is air stable, forming a surface layer that does not increase the recombination rate. We found that MBI luminesces at room temperature, with the vapor-processed films exhibiting superior photoluminescence (PL) decay times that are promising for photovoltaic applications. The thermodynamic, electronic, and structural features of MBI that are amenable to these properties are also present in other hybrid ternary bismuth halide compounds. Through MBI, we demonstrate a lead-free and stable alternative to MAPbX3 that has a similar electronic structure and nanosecond lifetimes.
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. rlzhoye@mit.edu.
authors: Robert L Z
authors: http://orcid.org/0000-0002-7675-0065
authors: RL
authors: Hoye
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Riley E
authors: http://orcid.org/0000-0003-2785-552X
authors: RE
authors: Brandt
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Anna
authors: A
authors: Osherov
authors: Colorado School of Mines, Golden, CO, 80401, USA.|National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO, 80401, USA.
authors: Vladan
authors: V
authors: Stevanović
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.|University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK.
authors: Samuel D
authors: http://orcid.org/0000-0002-8303-7292
authors: SD
authors: Stranks
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Mark W B
authors: http://orcid.org/0000-0002-1957-2979
authors: MW
authors: Wilson
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Hyunho
authors: H
authors: Kim
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Austin J
authors: AJ
authors: Akey
authors: National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO, 80401, USA.
authors: John D
authors: JD
authors: Perkins
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Rachel C
authors: RC
authors: Kurchin
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Jeremy R
authors: http://orcid.org/0000-0002-6616-9867
authors: JR
authors: Poindexter
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Evelyn N
authors: EN
authors: Wang
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Moungi G
authors: MG
authors: Bawendi
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors: Vladimir
authors: V
authors: Bulović
authors: Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. buonassisi@mit.edu.
authors: Tonio
authors: T
authors: Buonassisi
keywords: air stability; bismuth; materials science; organic-inorganic hybrids; perovskites