White light emission with unity efficiency from Cs2Na1-xAgxIn1-yBiyCl6 double perovskites: the role of bismuth and silver

Liu, Fang1; Simbula, Angelica1; Lai, Stefano1; Wu, Luyan1; Wang, Qingqian2; Marongiu, Daniela1; Pau, Riccardo1,3; Matta, Selene1; Pitzalis, Federico1; Lehmann, Alessandra Geddo1; Wang, Kai2; Filippetti, Alessio1,4; Quochi, Francesco1; Saba, Michele1; Mura, Andrea1; Bongiovanni, Giovanni1

2022-09-01

10.1039/d2tc02919g

Journal of Materials Chemistry C   影响因子和分区

2050-7526

2050-7534

Double perovskites Cs2Na1-xAgxIn1-yBiyCl6 can emit warm white light with almost unity quantum efficiency and are thus among the most promising materials for solid-state lighting. The emission spectrum is reproducible and the materials themselves are robust against degradation, as well as fabricated from earth-abundant, non-toxic precursors. The emission efficiency is however sensitive to the materials composition, with small variations modifying the photoluminescence quantum yield by more than an order of magnitude. We provide here a comprehensive, systematic study of the optical properties as a function of composition and identify the microscopic mechanism linking the presence of Bi and Ag to the high emission quantum yield. A 0.1% minimum fraction of Bi and Ag is found to trigger efficient emission of warm white light. Ag alloying is fundamental to obtain high emission yields. Continuous-wave spectroscopy measurements are complemented with ab initio computation of the electronic band structure in demonstrating that Bi strengthens optical absorption at the band gap edge of the double perovskites. In addition, it is found by combining time-resolved photoluminescence and transient absorption spectroscopy that Ag and Bi promote the formation of bright (radiative) self-trapped excitons, while inhibiting exciton relaxation into long-lived dark states.

SCI

英语

其他

PON "Ricerca e Innovazione" 2014-2020 - Fondo Sociale Europeo, Attraction and International Mobility[AIM1809115-2] ; Regione Autonoma della Sardegna through PO-FSE Sardegna["L. R. 7/2007","CRP3-114","CRP-17571","CRP-18353","CRP-18013","CRP-24978","31","52/36","SULCIS-820889","SULCIS-820947"] ; MUR (Italian Ministry of University and Research)[20155LECAJ] ; Fondazione di Sardegna[2F20000210007]

Materials Science ; Physics

Materials Science, Multidisciplinary ; Physics, Applied

WOS:000850905000001

ROYAL SOC CHEMISTRY

Web of Science

1.Univ Cagliari, Dipartimento Fis, I-09042 Monserrato, CA, Italy
2.Southern Univ Sci & Technol, Dept Elect & Elect Engn, Shenzhen 518055, Peoples R China
3.Univ Groningen, Zernike Inst Adv Mat, Nijenborgh 4, NL-09747 AG Groningen, Netherlands
4.Ist Off Mat CNR IOM Cagliari, I-09042 Monserrato, CA, Italy

Liu, Fang,Simbula, Angelica,Lai, Stefano,et al. White light emission with unity efficiency from Cs2Na1-xAgxIn1-yBiyCl6 double perovskites: the role of bismuth and silver[J]. Journal of Materials Chemistry C,2022.

Liu, Fang.,Simbula, Angelica.,Lai, Stefano.,Wu, Luyan.,Wang, Qingqian.,...&Bongiovanni, Giovanni.(2022).White light emission with unity efficiency from Cs2Na1-xAgxIn1-yBiyCl6 double perovskites: the role of bismuth and silver.Journal of Materials Chemistry C.

Liu, Fang,et al."White light emission with unity efficiency from Cs2Na1-xAgxIn1-yBiyCl6 double perovskites: the role of bismuth and silver".Journal of Materials Chemistry C (2022).