Rapid synthesis of hybrid methylammonium lead iodide perovskite quantum dots and rich MnI2 substitution favouring Pb-free warm white LED applications

Abstract

We present a facile room temperature synthesis of CH₃NH₃Pb_1−xMn_xI₃ perovskite quantum dots (PQDs) substituting manganese (Mn²⁺) at the lead (Pb²⁺) sites to minimize environmental pollution and make it commercially feasible. By varying the concentration of Mn²⁺ from 0 to 60%, the PQDs exhibit strong color tunability from red to orange color suggesting successful energy transfer due to Mn²⁺ inclusion. We observed a high external photoluminescence quantum yield (PLQY) of 98% for unsubstituted CH₃NH₃PbI₃ and >50% for up to 15% Mn²⁺ substituted PQDs. The average lifetime of PQDs was found to shorten with increasing Mn²⁺ replacement. We demonstrate a white LED prototype by employing the CH₃NH₃Pb_1−xMn_xI₃ PQDs with green QDs on a blue LED chip. The CRI and CCT value varying from 92 to 80 and 5100 K to 2900 K, respectively, indicate the usability of the Mn²⁺ substituted PQDs as efficient warm white LEDs with a promising CRI and good stability.