Tailoring optoelectronic performance through compositional engineering to optimize trap densities in Cs_xMA_(1-x)PbI3 perovskite nanowires

Organic-inorganic methylammonium lead iodide perovskite (MAPbI3) nanowires (NWs) have attracted significant attention in the realm of optoelectronic devices due to their outstanding optoelectronic properties. However, the persistent challenge of high trap densities has been a limiting factor in realizing their full potential in device performance. To address this challenge, we incorporated cesium (Cs) and systematically investigated the impact of Cs concentration on the trap densities and the optoelectronic characteristics of CsxMA(1-x)PbI3 NWs. Our findings unveiled an initial reduction in trap densities as Cs+ content increased, with the lowest point occurring at x = 0.2. However, beyond this threshold, trap densities began to rise, eventually surpassing those observed in pure MAPbI3 at x = 0.4. Furthermore, we fabricated single NW photodetectors to assess how Cs+ content influenced optoelectronic properties. The results indicated that Cs+ incorporation led to enhancements in photocurrent and response speed, with the optimal performance observed at x = 0.2. Our study provides valuable insights into the role of Cs+ incorporation in tailoring the optoelectronic properties of perovskite NWs. © 2024 The Author(s).