Himanshu Bhatt1,Tanmay Goswami1,Hirendra Ghosh2
Institute of Nano Science and Technology (INST), Mohali1,National Institute of Science Education and Research (NISER)2
Himanshu Bhatt1,Tanmay Goswami1,Hirendra Ghosh2
Institute of Nano Science and Technology (INST), Mohali1,National Institute of Science Education and Research (NISER)2
Band structure modulation in heterostructure has emerged as a highly effective strategy for fabricating advanced optoelectronic devices. In this work, we have designed a CsPbI<sub>3</sub>-WS<sub>2</sub> (CPI-WS<sub>2</sub>) heterosystem and employed transient absorption (TA) spectroscopy to gather a comprehensive understanding of charge carrier dynamics. TA study demonstrated the charge delocalization at the interface of CPI and WS<sub>2</sub>. Due to the quasi-type II integration of CPI and WS<sub>2</sub>, the charge separation in this heterosystem is not very effective, which would restrict their utilization in photovoltaic applications. To further improvise the charge separation, Ni atoms were introduced as dopants into CPI nanocrystals. Ultraviolet electron spectroscopy (UPS) suggested that the homovalent doping elevated the band positions of CPI and resulted in a type II band configuration with WS<sub>2</sub>. TA analysis revealed the spontaneous carrier’s separation in band-modulated heterosystem due to the isolation of electrons and holes in discrete semiconductors. These spectroscopy findings were correlated with the optoelectronic performance of heterostructure-based devices. Enhanced charge separation within a doped heterosystem leads to superior optoelectronic performance compared to undoped heterosystems. Our findings showed that the band level of engineering encourages the segregation of charge carriers at the hetero-interface, which would be extremely impactful for designing heterostructure-based optoelectronic systems.