Centimeter-Sized Inorganic Lead Halide Perovskite CsPbBr3 Crystals Grown by an Improved Solution Method

摘要

As a member of the lead-halide perovskite family, inorganic perovskite CsPbBr3 exhibits excellent optical and electrical properties with higher stability to the environment. However, former efforts to obtain large-size CsPbBr3 single crystals with satisfactory quality using low temperature solution methods reached limited results. In this work, we have studied the growth of CsPbBr3 crystals using the antisolvent vapor-assisted crystallization (AVC) method. By adjusting the mole ratio of PbBr2 and CsBr, the phase diagram of the final products is acquired. Five regions are identified, including the Cs4PbBr6 single phase region, Cs4PbBr6 and CsPbBr3 two phases region, CsPbBr3 single phase region, CsPbBr3 and PbBr2 center dot 2[(CH3)(2)SO] metastable two phases region, and CsPbBr3 and PbBr2 center dot 2[(CH3)(2)SO] two phases region. Three methods are adopted to improve the size and crystalline quality of CsPbBr3. The growth rate is effectively tailored by diluting the antisolvent MeOH solution using DMSO to reduce the MeOH vapor pressure. Centimeter-size bright CsPbBr3 crystals have been obtained. The room temperature bandgap of CsPbBr3 is estimated at similar to 2.29 eV by the transmission spectra. The photoluminescence spectra show two strong emission peaks, located at 530 and 555 nm, respectively, which are related to the free and bond excitons. The resistivity is as large as 2.1 X 10(9)Omega cm(-3). Hall effect measurements demonstrate the CsPbBr3 is p-type conductivity with a hole carrier concentration of 4.55 X 10(7) cm(-3) and the mobility of 143 cm(2) s(-l). The resulting Au/CsPbBr3/Au device exhibits strong photoresponse to optical light, with an on-off ratio of two orders under a light emitting diode (similar to 1 mW/cm(2)) with a wavelength of 365-420 nm. Our research would shed more light on the growth and the photoresponse properties of CsPbBr3 crystals.