Colloidal AInSe2 (A = K, Rb, Cs) Nanocrystals with Tunable Crystal and Band Structures

Zhaohong Sun; Carlos Mora Perez; Oleg V Prezhdo; Richard L Brutchey

doi:10.1021/acsnanoscienceau.4c00022

Colloidal AInSe₂ (A = K, Rb, Cs) Nanocrystals with Tunable Crystal and Band Structures

ACS Nanosci Au. 2024 Oct 11;4(6):381-390. doi: 10.1021/acsnanoscienceau.4c00022. eCollection 2024 Dec 18.

Authors

Zhaohong Sun¹, Carlos Mora Perez¹, Oleg V Prezhdo¹, Richard L Brutchey¹

Affiliation

¹ Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.

Abstract

Wide band gap AInSe₂ (A = K, Rb, Cs) is an important interlayer material for improving the efficiency of Cu(In,Ga)(S,Se)₂ (CIGS) solar cells. Compared to high-vacuum deposition and solid-state synthesis, a less energy-intensive method is of interest for its fabrication. Herein, we present the rapid, low-temperature colloidal synthesis of AInSe₂ nanocrystals that opens a pathway for convenient solution processing. The crystal structures and electronic band structures of the nanocrystals were studied, and their particle morphology was found to be dependent on the choice of alkali metal and selenium precursors. Homogeneous solid solution (K,Rb,Cs)InSe₂ nanocrystals were synthesized using a mixture of alkali metal precursors. Their compositions, lattice parameters, and band gaps were easily tuned based on the K:Rb:Cs precursor ratio, providing potential for interface engineering of CIGS nanocrystal-based solar cells.