Charge Carriers in Planar and Meso-Structured Organic-Inorganic Perovskites: Mobilities, Lifetimes, and Concentrations of Trap States.
Efficient solar cells have been obtained using thin films of solution-processed organic-inorganic perovskites. However, there remains limited knowledge about the relationship between preparation route and optoelectronic properties. We use complementary time-resolved microwave conductivity (TRMC) and photoluminescence (PL) measurements to investigate the charge carrier dynamics in thin planar films of CH3NH3PbI(3-x)Cl(x), CH3NH3PbI3, and their meso-structured analogues. High mobilities close to 30 cm(2)/(V s) and microsecond-long lifetimes are found in thin films of CH3NH3PbI(3-x)Cl(x), compared to lifetimes of only a few hundred nanoseconds in CH3NH3PbI3 and meso-structured perovskites. We describe our TRMC and PL experiments with a global kinetic model, using one set of kinetic parameters characteristic for each sample. We find that the trap density is less than 5 × 10(14) cm(-3) in CH3NH3PbI(3-x)Cl(x), 6 × 10(16) cm(-3) in the CH3NH3PbI3 thin film and ca. 10(15) cm(-3) in both meso-structured perovskites. Furthermore, our results imply that band-to-band recombination is enhanced by the presence of dark carriers resulting from unintentional doping of the perovskites. Finally, our general approach to determine concentrations of trap states and dark carriers is also highly relevant to other semiconductor materials.
†Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
Eline M
EM
Hutter
‡Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Giles E
GE
Eperon
§Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.|∥Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Samuel D
SD
Stranks
†Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
Tom J
TJ
Savenije
meso-structured perovskites; nonradiative decay; organic−inorganic metal halide perovskites; photoluminescence; time-resolved microwave conductivity; trap states