Manipulation of luminescence activity by interfacial engineering via surface treatment of TiO2 nanorods in the core/shell/mixed halide CH3NH3PbI3-xClx perovskite heterostructures

Abstract

Efficient charge transfer between the various layers in a solar cell requires proper modification of interfaces. Multi-step hydrothermal processing have been adopted for the fabrication of Core/shell TiO2/SrTiO3 nanorod array on the Fluorine-doped Tin Oxide and TiO2 surfaces. Nanorods were treated with strontium for surface passivation via hydrothermal technique which is found to be critical in tuning the optoelectronic properties. For individual layers in thin films, various experimental techniques were used to study structural, morphological, optical and spectroscopic properties. Raman spectroscopy, reveal presence of rutile and anatase phase for TiO2 nanorods which corelates with the crystal structure of compact layer and nanorods. Afterwards a perovskite layer was deposited on top of nanorods to study photo-luminescence response which successfully revealed that strontium treatment of nanorods suppresses the recombination of charge carriers. The observations and results discussed in this article will be helpful in improving the optoelectronic properties of the material and could lead to improved efficiency of perovskite solar cells.