Lead-based halide perovskites (HPs) have become a center
of attention
in the field of optoelectronics; however, the toxic nature of lead
is a bottleneck in their long-term commercial exploration. The Sn-based
HPs are being considered as potential substitutes; however, their
poor stability under ambient conditions is a major challenge. To address
this, we have attempted postpassivation of CsSnBr3 with
didodecyldimethylammonium (DDAB), a biexchange ligand. This ligand
replaces the weak surface capping of OAm with DDA+ and
also fills the halide (Br) vacancies on the HP surface, thereby increasing
the stability of the lead-free CsSnBr3 HPs. In addition
to improved stability, the DDAB-functionalized CsSnBr3 HPs
show ∼5.5 times enhancement in the PL intensity. The DDAB-functionalized
CsSnBr3 HPs with shorter chain lengths of DDAB (which might
result in improved carrier current), prolonged stability, and improved
PL behavior could be a better choice for optoelectronic applications.