Investigation of self-powered photoresponse performance of all inorganic lead-free halide perovskites (CsSnCl3) nanocrystals (NCs) decorated Er:ZnO nanowires/Si heterojunctions

Abstract

In the current study, we report the all-inorganic lead-free halide perovskites-oxide heterojunction based optoelectronic device fabrications on Si substrate by employing cost-effective chemical bath deposition (CBD) and hot-injection techniques. The selective rare-earth doping of erbium (Er) in ZnO nanowires is performed by employing double-step CBD technique on Si platform for developing a superior heterojunction between Er:ZnO and Si. Furthermore, lead-free perovskites NCs of CsSnCl3 are synthesized by using cost-effective hot-injection method and such NCs are decorated over the Er:ZnO nanowires to passivate the surface defect states. The effect of Er-doping and CsSnCl3 incorporation on structural, optical and luminescence properties of nanowire heterojunctions has been successfully investigated by employing XRD, UV-VIS and PL. The crystal structure of Er:ZnO and Er: ZnO-CsSnCl3 heterojunctions has been analyzed using X-Ray Diffraction (XRD) technique, which confirms the polycrystalline nature of nanowires with the formation of a highly crystalline cubic phase of CsSnCl3. The optical absorption of Er:ZnO nanowires and CsSnCl3 NCs are studied by using ultraviolet-visible (UV-VIS) spectroscopy and corresponding energy bandgaps are estimated to be 3.31 eV and 3.24 eV, respectively. The oxygen vacancies and complex defect states are minimized in ZnO nanowires by Er-doping and perovskites NCs addition and such CsSnCl3 decorated Er:ZnO nanowires exhibit enhanced UV luminescence as compared to undoped ZnO. Finally, photoresponse of undoped, Er-doped and CsSnCl3 incorporated ZnO nanowires/Si heterojunction has been studied by measuring dark and photo-current and photo-current switching at UV-A wavelength region and such heterojunctions shows excellent photoresponse under self-powered mode. Therefore, such perovskites incorporated Er:ZnO nanowires/Si heterojunction can be a potential candidate for fabricating a highly responsive self-powered UV-detector (UV-A).