TY - JOUR
T1 - Vacancy-Ordered Double Perovskite Rb2ZrCl6−xBrx
T2 - Facile Synthesis and Insight into Efficient Intrinsic Self-Trapped Emission
AU - Zheng, Kun
AU - Chen, Bingkun
AU - Xie, Lingling
AU - Li, Xitao
AU - Lu, Bingheng
AU - Wang, Min
AU - Wu, Yafeng
AU - Jiang, Ting
AU - Zhang, Fa
AU - Li, Xu
AU - Wang, Yongtian
N1 - Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2022/1/18
Y1 - 2022/1/18
N2 - Lead-free vacancy-ordered double perovskites with formula of A2M(IV)X6 have become promising alternatives to lead halide perovskites. Herein, novel direct bandgap lead-free vacancy-ordered double perovskites Rb2ZrCl6−xBrx (0 ≤ x ≤ 2) with highest photoluminescence quantum yield (PLQY) of 90% are synthesized by using a facile wet grinding approach. Experimental and theoretical analyses demonstrate that the bright emissions originate from the self-trapped excitons (STEs). Additionally, thermally activated delayed fluorescence (TADF) is observed in these perovskites, confirmed by temperature-dependent steady-state PL spectra and time-resolved PL spectra measurements. The competitive equilibrium relationship is demonstrated further between the singlet STEs and the triplet STEs of Rb2ZrCl6−xBrx interrelated to temperature. Meanwhile, satisfying the Vegard's law, the optical bandgap of Rb2ZrCl6−xBrx decreases linearly from 3.895 to 3.778 eV with x increasing. Furthermore, density functional theory (DFT) calculations prove the highly localized electronic states generated in flat electronic bands of Rb2ZrCl6−xBrx, as evidence by the presence of self-trapped state in [ZrCl6−xBrx]2− octahedra, and the energy level of the halogen 3p orbitals is the key factor that dictates their bandgaps.
AB - Lead-free vacancy-ordered double perovskites with formula of A2M(IV)X6 have become promising alternatives to lead halide perovskites. Herein, novel direct bandgap lead-free vacancy-ordered double perovskites Rb2ZrCl6−xBrx (0 ≤ x ≤ 2) with highest photoluminescence quantum yield (PLQY) of 90% are synthesized by using a facile wet grinding approach. Experimental and theoretical analyses demonstrate that the bright emissions originate from the self-trapped excitons (STEs). Additionally, thermally activated delayed fluorescence (TADF) is observed in these perovskites, confirmed by temperature-dependent steady-state PL spectra and time-resolved PL spectra measurements. The competitive equilibrium relationship is demonstrated further between the singlet STEs and the triplet STEs of Rb2ZrCl6−xBrx interrelated to temperature. Meanwhile, satisfying the Vegard's law, the optical bandgap of Rb2ZrCl6−xBrx decreases linearly from 3.895 to 3.778 eV with x increasing. Furthermore, density functional theory (DFT) calculations prove the highly localized electronic states generated in flat electronic bands of Rb2ZrCl6−xBrx, as evidence by the presence of self-trapped state in [ZrCl6−xBrx]2− octahedra, and the energy level of the halogen 3p orbitals is the key factor that dictates their bandgaps.
UR - http://www.scopus.com/inward/record.url?scp=85118469079&partnerID=8YFLogxK
U2 - 10.1002/adom.202101661
DO - 10.1002/adom.202101661
M3 - Article
AN - SCOPUS:85118469079
SN - 2195-1071
VL - 10
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 2
M1 - 2101661
ER -