Nanoscale charge localization induced by random orientations of organic molecules in hybrid perovskite CH3NH3PbI3.

Journal Article · Thu Jan 01 00:00:00 EST 2015 · Nano Letters

DOI:https://doi.org/10.1021/nl503494y· OSTI ID:1512156

Ma, Jie; Wang, Lin-Wang

Perovskite-based solar cells have achieved high solar-energy conversion efficiencies and attracted wide attentions nowadays. Despite the rapid progress in solar-cell devices, many fundamental issues of the hybrid perovskites have not been fully understood. Experimentally, it is well-known that in CH3NH3PbI3 the organic molecules CH3NH3 are randomly orientated at the room temperature, but the impact of the random molecular orientation has not been investigated. Because of the dipole moment of the organic molecule, the random orientation creates a novel system with long-range potential fluctuations unlike alloys or other conventional disordered systems. Using linear scaling ab initio methods, we find that the charge densities of the conduction band minimum and the valence band maximum are localized in nanoscales due to the potential fluctuations. The charge localization causes electron-hole separation and reduces carrier recombination rates, which may contribute to the long carrier lifetime observed in experiments.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Chemical Sciences, Geosciences & Biosciences Division (SC-22.1)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1512156
• Journal Information: Nano Letters, Vol. 15, Issue 1; ISSN 1530-6984
• Country of Publication: United States
• Language: English