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

As a member of the lead-halide perovskite family, inorganic perovskite CsPbBr 3 exhibits excellent optical and electrical properties with higher stability to the environment. However, former efforts to obtain large-size CsPbBr 3 single crystals with satisfactory quality using low temperature solution methods reached limited results. In this work, we have studied the growth of CsPbBr 3 crystals using the antisolvent vapor-assisted crystallization (AVC) method. By adjusting the mole ratio of PbBr 2 and CsBr, the phase diagram of the final products is acquired. Five regions are identified, including the Cs 4 PbBr 6 single phase region, Cs 4 PbBr 6 and CsPbBr 3 two phases region, CsPbBr 3 single phase region, CsPbBr 3 and PbBr 2 ·2[(CH 3 ) 2 SO] metastable two phases region, and CsPbBr 3 and PbBr 2 ·2[(CH 3 ) 2 SO] two phases region. Three methods are adopted to improve the size and crystalline quality of CsPbBr 3 . The growth rate is effectively tailored by diluting the antisolvent MeOH solution using DMSO to reduce the MeOH vapor pressure. Centimeter-size bright CsPbBr 3 crystals have been obtained. The room temperature bandgap of CsPbBr 3 is estimated at ∼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 × 10 9 Ω·cm. Hall effect measurements demonstrate the CsPbBr 3 is p-type conductivity with a hole carrier concentration of 4.55 × 10 7 cm –3 and the mobility of 143 cm 2 V –1 s –1 . The resulting Au/CsPbBr 3 /Au device exhibits strong photoresponse to optical light, with an on–off ratio of two orders under a light emitting diode (∼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 CsPbBr 3 crystals.