Controllable doping of semiconductors is a fundamental technological requirement for electronic and optoelectronic devices. As intrinsic semiconductors, hybrid perovskites have so far been a phenomenal success in photovoltaics. The inability to dope these materials heterovalently (or aliovalently) has greatly limited their wider utilizations in electronics. Here we show an efficient in situ chemical route that achieves the controlled incorporation of trivalent cations (Bi3+, Au3+, or In3+) by exploiting the retrograde solubility behavior of perovskites. We term the new method dopant incorporation in the retrograde regime. We achieve Bi3+ incorporation that leads to bandgap tuning (∼300 meV), 104 fold enhancement in electrical conductivity, and a change in the sign of majority charge carriers from positive to negative. This work demonstrates the successful incorporation of dopants into perovskite crystals while preserving the host lattice structure, opening new avenues to tailor the electronic and optoelectronic properties of this rapidly emerging class of solution-processed semiconductors. © 2016 American Chemical Society.
KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): URF/1/1373-01-01, URF/1/1741-01-01, URF/1/2268-01-01
Acknowledgements: The authors acknowledge the support of Awards URF/1/2268-01-01, URF/1/1741-01-01, and URF/1/1373-01-01 made by King Abdullah University of Science and Technology (KAUST). We acknowledge the financial support from King Abdulaziz City for Science and Technology (KACST), Grant KACST TIC R2-FP-008. The authors thank Y. Losovyj for XPS date collection and partial analysis, and P. Dowben for the useful discussions. Access to XPS at the Nanoscience Characterization Facility of Indiana University's Nanoscience Center was provided by the NSF (Award DMR MRI-1126394).