Direct-indirect character of the bandgap in methylammonium lead iodide perovskite

Eline M. Hutter, María C. Gélvez-Rueda, Anna Osherov, Vladimir Bulović, Ferdinand C. Grozema, Samuel D. Stranks, Tom J. Savenije*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

294 Citations (Scopus)
6 Downloads (Pure)


Metal halide perovskites such as methylammonium lead iodide (CH3 NH3 PbI3) are generating great excitement due to their outstanding optoelectronic properties, which lend them to application in high-efficiency solar cells and light-emission devices. However, there is currently debate over what drives the second-order electron-hole recombination in these materials. Here, we propose that the bandgap in CH3 NH3 PbI3 has a direct-indirect character. Time-resolved photo-conductance measurements show that generation of free mobile charges is maximized for excitation energies just above the indirect bandgap. Furthermore, we find that second-order electron-hole recombination of photo-excited charges is retarded at lower temperature. These observations are consistent with a slow phonon-assisted recombination pathway via the indirect bandgap. Interestingly, in the low-temperature orthorhombic phase, fast quenching of mobile charges occurs independent of the temperature and photon excitation energy. Our work provides a new framework to understand the optoelectronic properties of metal halide perovskites and analyse spectroscopic data.

Original languageEnglish
Pages (from-to)115-120
Number of pages6
JournalNature Materials
Issue number1
Publication statusPublished - 2017


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