Eu(II)‐Based Quaternary Chalcogenides with Noncentrosymmetric Structures Stabilized by Site Disorder of d10 Metal Cations
Year: 2025
Type: article
Abstract: Quaternary metal‐chalcogenides combining rare‐earth cations with late transition metal cations are attracting growing attention for their optical properties, such as for solar energy conversion or second harmonic generation. Synthetic explorations of the II3‐I2‐IV2‐Ch8 family (II = Eu; I = Cu or Ag; IV = Si, Ch = S or Se) have yielded Eu3Ag2Si2S8 (1) and Eu3Cu1.08(1)Si2.42(1)Se8 (2). Their structures have been characterized by X‐ray diffraction to form in the noncentrosymmetric space group I3d and to exhibit two distinct types of mixed‐site occupancies, for the Ag(I) cations in 1 and mixed Cu(I)/Si(IV) cations in 2. In both, the cation disorder occurs to achieve charge balancing with the chalcogenide anions. A high yield of 1 can be achievedwith optical measurements showing indirect and direct band transitions of ≈2.2(1) and ≈2.4(1) eV, respectively. Its second harmonic generation response is found to be relatively strong, approximately 0.9 × AgGaS2, confirming its noncentrosymmetric structure. Band structure calculations reveal the valence and conduction band edges stem predominantly from the filled Ag(I)/Cu(I)‐based states and empty Si(IV)‐based states, respectively, with additional contributions from the chalcogenide anions. Calculation results also show that cation disorder facilitates a reduction in the antibonding interactions between the Ag(I)/Cu(I) d‐based and chalcogenide p‐based states.
Institutions: Baylor University, University of Houston
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,960
Awards: G1130558632, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G1937133092, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), Flux Mediated Synthesis of Cu(I)-Oxide Semiconductors for Clean Energy Application, Flux Mediated Synthesis of Cu(I)-Oxide Semiconductors for Clean Energy Application, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI
OpenAlex ID: W4409431759