Modulating Excitonic Recombination Effects through One-Step Synthesis of Perovskite Nanoparticles for Light-Emitting Diodes

Sneha A. Kulkarni, Subas Muduli, Guichuan Xing, Natalia Yantara, Mingjie Li, Shi Chen, Tze Chien Sum, Nripan Mathews, Tim J. White, Subodh G. Mhaisalkar

Research output: Journal article publicationJournal articleAcademic researchpeer-review

12 Citations (Scopus)


The primary advantages of halide perovskites for light-emitting diodes (LEDs) are solution processability, direct band gap, good charge-carrier diffusion lengths, low trap density, and reasonable carrier mobility. The luminescence in 3 D halide perovskite thin films originates from free electron-hole bimolecular recombination. However, the slow bimolecular recombination rate is a fundamental performance limitation. Perovskite nanoparticles could result in improved performance but processability and cumbersome synthetic procedures remain challenges. Herein, these constraints are overcome by tailoring the 3 D perovskite as a near monodisperse nanoparticle film prepared through a one-step in situ deposition method. Replacing methyl ammonium bromide (CH3NH3Br, MABr) partially by octyl ammonium bromide [CH3(CH2)7NH3Br, OABr] in defined mole ratios in the perovskite precursor proved crucial for the nanoparticle formation. Films consisting of the in situ formed nanoparticles displayed signatures associated with excitonic recombination, rather than that of bimolecular recombination associated with 3 D perovskites. This transition was accompanied by enhanced photoluminescence quantum yield (PLQY≈20.5 % vs. 3.40 %). Perovskite LEDs fabricated from the nanoparticle films exhibit a one order of magnitude improvement in current efficiency and doubling in luminance efficiency. The material processing systematics derived from this study provides the means to control perovskite morphologies through the selection and mixing of appropriate additives.

Original languageEnglish
Pages (from-to)3818-3824
Number of pages7
Issue number19
Publication statusPublished - 9 Oct 2017
Externally publishedYes


  • exciton formation
  • light emitting diodes
  • methyl ammonium lead bromide
  • nanoparticles
  • perovskites

ASJC Scopus subject areas

  • Environmental Chemistry
  • General Chemical Engineering
  • General Materials Science
  • General Energy


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