Photoluminescence, Raman and photosensitive dielectric properties of lead-free antimony-based Cs3Sb2Br9 single crystals for energy storage devices

Abstract

• Cs3Sb2Br9 SCs with the trigonal crystal structure and the P 3 m 1 space group were prepared by the slow cooling method. • The temperature-dependent photoluminescence analysis shows that Cs3Sb2Br9 has a low thermal activation energy of 54.7 meV. • Temperature dependence of Raman scattering in Cs3Sb2Br9 proves that there is no structural phase transition in the range of 50-300 K. • The Debye-type process in the SCs is interpreted through the complex modulus formalism. • The M′′(ω) plots presented a reversible shift under light-on conditions. • The light-sensitive dielectric and conductivity relaxation mechanisms are studied through the modified Cole-Cole and Debye-type relaxation approaches. Recently, all-inorganic lead-free halide perovskites have drawn the researchers’ attention because of their excellent stability, lower toxicity, and good optoelectronic characteristics. This paper first investigates both temperature-dependent PL and Raman spectrum of all-inorganic antimony-based Cs 3 Sb 2 Br 9 single crystals (SCs). Secondly, the light-sensitive dielectric and conductivity comportment in Cs 3 Sb 2 Br 9 SCs by electrochemical impedance spectroscopy (EIS), which is used under both dark and light conditions by displaying these conditions in sequence. The photosensitive dielectric and conductivity comportment are studied through the modified Cole-Cole and Debye-type relaxation approaches. The dipolar relaxation behaviors, which are assisted by the reversible photo-induced trap in Cs 3 Sb 2 Br 9 SCs are interpreted by a comprehensive study of the reversible variation found in the modulus crest frequencies. The conductivity is illustrated in terms of Jonncher's s power law. The Debye-type nature of relaxation is additionally confirmed by the power factor (n) value, which is almost equal to 1. This paper presents thorough knowledge and fresh ideas of light-sensitive dielectric and conductivity relaxation processes in all inorganic lead-free perovskite SCs. This scientific research will inspire the coming pattern of the perovskite SCs-based energy storage system.