Highly Controllable Synthesis and DFT Calculations of Double/Triple-Halide CsPbX₃ (X = Cl, Br, I) Perovskite Quantum Dots: Application to Light-Emitting Diodes.

Xinyue Lao,Xiyu Li,Hans Ågren,Guanying Chen

doi:10.3390/nano9020172

Abstract

Although all-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have evoked exciting new opportunities for optoelectronic applications due to their remarkable optical properties, their emission color tunability has not been investigated to any appreciable extent. In this work, double/triple CsPbX3 perovskite quantum dots with precise ratios of Cl/Br or Br/I are synthesized and their luminescence (410–700 nm) is explored. A group of down-converted CsPbX3 (X = Cl, Br, I) perovskite quantum dot light-emitting diode (LED) devices were constructed to demonstrate the potential use of such double/triple-halide CsPbX3 perovskite quantum dots with full-spectrum luminescence. Based on density functional theory, we theoretically explored the properties of CsPbX3 with double/triple anion atoms. The calculated band gaps provided strong support that the full-spectrum luminescence (410–700 nm) of double/triple CsPbX3 can be realized with the change of the mixed-halide ratios, and hence that such PQDs are of potential use in optoelectronic devices.

Highlights

During the past two decades, colloidal semiconductor quantum dots (QDs) have attracted a great deal of attention due to their unique quantum-confined optical and electrical properties [1,2]—namely, that the discrete electron energy levels near the Fermi energy level split from the continuum when the particle size is smaller than or comparable to the Bohr exciton radius
CsPbX3 perovskite quantum dots (PQDs) with tunable and bright photoluminescent (PL) properties have been synthesized with different methods such as hot injection [11], anion exchange [12], ultrasonication [13], solvothermal [14], and microwave-assisted [15] methods, and different shapes have been designed [14] to obtain better photoelectric performance
Significant progress has been made in the synthesis and application of CsPbX3 PQDs, they still need to be explored by providing a comprehensive composition-defined luminescence and by theoretical calculation of structure and properties like band gaps and formation energies

Summary

Introduction

During the past two decades, colloidal semiconductor quantum dots (QDs) have attracted a great deal of attention due to their unique quantum-confined optical and electrical properties [1,2]—namely, that the discrete electron energy levels near the Fermi energy level split from the continuum when the particle size is smaller than or comparable to the Bohr exciton radius. We report the synthesis of double/triple-halide CsPbX3 (X = Cl, Br, I) PQDs with precise ratios of Cl/Br or Br/I, using the hot-injection method.

Results

Conclusion