Transition from Positive to Negative Photoconductance in Doped Hybrid Perovskite Semiconductors
Li, Jin Ling
Abdelhady, Ahmed L.
Saidaminov, Makhsud I.
Wei, Su Huai
KAUST DepartmentMaterials Science and Engineering Program
Physical Sciences and Engineering (PSE) Division
KAUST Solar Center (KSC)
KAUST Catalysis Center (KCC)
KAUST Grant Number3737
Embargo End Date2020-01-01
Permanent link to this recordhttp://hdl.handle.net/10754/656739
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AbstractHalide perovskites are known to be photoconductive for more than half a century, and their efficient photocarrier generation gives rise to positive photoconductivity (PPC). In this work, the discovery of negative photoconductivity (NPC) in hybrid perovskite CH3NH3PbBr3 after Bi doping is reported. Transient photoconductivity measurements reveal a surprising bipolar behavior with a fast positive response followed by exponential negative photocurrent decay, resulting in an equilibrium photocurrent even below the dark level. The NPC effect in Bi-doped CH3NH3PbBr3 is among the largest ones reported so far for semiconductors. It is proposed that the transition to negative photoconductance is related to the presence of DX-like centers in Bi-doped halide perovskites, similar to doped III–V and chalcopyrite semiconductors. Such photogenerated DX-like centers in the Bi-doped CH3NH3PbBr3 can trap mobile band electrons and enhance charge recombination, thus reducing the conductivity. This mechanism is consistent with the observations of crossover from PPC to NPC as functions of temperature, composition, and illumination. The results underscore the importance of defect engineering for tuning the optoelectronic properties of halide perovskites.
SponsorsM.A.H. and J.-L.L. contributed equally to this work. Research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST). D.B. acknowledges the KAUST competitive research grant (CRG7, No. 3737) for financial support. The work at CSRC was supported by the National Key Research and Development Program of China under Grant No. 2016YFB0700700, the National Nature Science Foundation of China under Grant Nos. 51672023, 11634003, and U1530401; and the Science Challenge Project under Grant No. TZ20160003.
JournalAdvanced Optical Materials