Hexadecylpyridinium bromides as a new capping agent for improving stability and luminescence of cesium lead bromide perovskites.

Because of exception properties, inorganic halide perovskites are promising materials for numerous applications. The efficiency of these materials are evaluated based on their photoluminescence quantum yield, which is the key indicator and proportional to the stability of the perovskite. Hence, to limit the instability of the perovskites, addition of surfactant as ligand has been applied during synthesis of nanoparticle based inorganic perovskite CsPbBr. As far as we know, only a few researchers have studied the impact of hexadecylpyridinium bromide (CPB) on the stability of the crystal structure of CsPbBr. In this work, we present a novel approach for lead halide perovskites by incorporating CPB to primarily maintain the perovskite's crystal structure, and later on to enhance the stability of CsPbBr NPs while boosting its photoluminescence quantum yield (PLQY). Results showed that CPB enhanced the thermal stability and boosted the PLQY to 90 %. Moreover, CPB had proven its efficiency as a capping agent preventing the exchange of anion between bromide and iodide ions in presence of lead iodide.