Suppression of Photoexcited Small Polarons-Mediated Energy Transfer to Boost Photoluminescence of Lanthanide-Titanium Nanoclusters

Feng Jiang; Shengrong He; Yuan Ji; Jun Yin; Yan Cong; Weinan Dong; Xin Li; Yu Zhang; Zhennan Wu; Xue Bai

doi:10.1021/acs.nanolett.4c05982

Suppression of Photoexcited Small Polarons-Mediated Energy Transfer to Boost Photoluminescence of Lanthanide-Titanium Nanoclusters

Nano Lett. 2025 Jan 7. doi: 10.1021/acs.nanolett.4c05982. Online ahead of print.

Authors

Feng Jiang^{1

2}, Shengrong He², Yuan Ji¹, Jun Yin³, Yan Cong⁴, Weinan Dong², Xin Li², Yu Zhang², Zhennan Wu², Xue Bai²

Affiliations

¹ College of Physics, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
² State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
³ Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon 999077, Hong Kong, P. R. China.
⁴ Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Dalian Minzu University, Dalian 11660, China.

PMID: 39772769
DOI: 10.1021/acs.nanolett.4c05982

Abstract

Lanthanide (Ln³⁺)-titanium-based molecular nanoclusters (NCs) have attracted much attention due to their atomically precise total structure and promising optical behavior, while there is still minimal cognition of structure-dictated electron relaxation dynamics in such an NCs regime with unsatisfied photoluminescence quantum yield (PLQY, in general below 20%). Herein, the photoexcited small polarons (i.e., local electron-phonon coupling) are identified and emphasized in modulating the emission of Ln³⁺ NCs. Taking 4-tert-butylbenzoate coordinated Eu₂Ti₄ NCs as a model, the excited electron is capable of being captured by the Ti⁴⁺ to form the Ti³⁺-dominated small polarons, which allows influencing the ligands-sensitive antenna effect for Eu³⁺ emission. Most importantly, by chelating the Eu₂Ti₄ NCs with Eu₃Ti₃ units bilaterally, the evolved Eu₈Ti₁₀ NCs perform suppressed lattice vibration and therefore eliminate the photoexcited small polaron-mediated energy transfer, giving a remarkable enhancement in PLQY, from 17.6% to 73.1%.

Keywords: lanthanide−titanium nanoclusters; luminescent nanoclusters; metal nanoclusters; photoexcited small polarons.