Related Experiment Video
Updated: Nov 19, 2025

A Modular Microfluidic Technology for Systematic Studies of Colloidal Semiconductor Nanocrystals
Published on: May 10, 2018
Multidimensional coherent spectroscopy reveals triplet state coherences in cesium lead-halide perovskite nanocrystals
Albert Liu1, Diogo B Almeida1, Luiz G Bonato2
1Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA.
Abstract:
Advances in optoelectronics require materials with novel and engineered characteristics. A class of materials that has garnered tremendous interest is metal-halide perovskites, stimulated by meteoric increases in photovoltaic efficiencies of perovskite solar cells. In addition, recent advances have applied perovskite nanocrystals (NCs) in light-emitting devices. It was found recently that, for cesium lead-halide perovskite NCs, their unusually efficient light emission may be due to a unique excitonic fine structure composed of three bright triplet states that minimally interact with a proximal dark singlet state. To study this fine structure without isolating single NCs, we use multidimensional coherent spectroscopy at cryogenic temperatures to reveal coherences involving triplet states of a CsPbI3 NC ensemble. Picosecond time scale dephasing times are measured for both triplet and inter-triplet coherences, from which we infer a unique exciton fine structure level ordering composed of a dark state energetically positioned within the bright triplet manifold.
Related Concept Videos
Electron Configuration of Multielectron Atoms
UV–Vis Spectroscopy: Molecular Electronic Transitions
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in...
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule

