1
|
Xie HM, Li SJ, Zhang PY, Feng J, Li S, Yang G. Insights into the Luminescence Thermochromism of a Triarylboron Derivative: The Role of Intramolecular Group Interaction. J Phys Chem A 2020; 124:889-897. [PMID: 31922413 DOI: 10.1021/acs.jpca.9b09834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The organic fluorescent probes for temperature have received increasing interest due to their extremely high spatial and temporal resolution. A few of triarylboron derivatives, as almost the only molecular probes consisting of a single luminophore, have the ability to change their luminescent color at different temperatures. The mechanism of their luminescence thermochromism is controversial. Herein, several spectral experiments, along with time-dependent density functional theory (TDDFT) and coupled-cluster (CC) calculations, are carried out to elucidate the temperature-dependent luminescence. The CC rather than the TDDFT methods give a relatively reasonable explanation for the experimental results. Consequently, the thermochromism is now considered as the result of conformational thermal equilibria that occur in both the excited and ground states. Besides, an unusual conformer with intramolecular excimer characteristic plays a crucial role in the attractive luminescence behavior.
Collapse
Affiliation(s)
- Hui-Ming Xie
- College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China
| | - Shao-Ju Li
- College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China
| | - Pan-Yi Zhang
- College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China
| | - Jiao Feng
- Institute of Chemistry & University of Chinese Academy of Sciences , Chinese Academy of Sciences , Beijing 100190 , PR China
| | - Shayu Li
- College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China
| | - Guoqiang Yang
- Institute of Chemistry & University of Chinese Academy of Sciences , Chinese Academy of Sciences , Beijing 100190 , PR China
| |
Collapse
|
2
|
Ban X, Jiang W, Sun K, Xie X, Peng L, Dong H, Sun Y, Huang B, Duan L, Qiu Y. Bipolar host with multielectron transport benzimidazole units for low operating voltage and high power efficiency solution-processed phosphorescent OLEDs. ACS APPLIED MATERIALS & INTERFACES 2015; 7:7303-7314. [PMID: 25785899 DOI: 10.1021/acsami.5b00510] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two soluble bipolar host materials (mCP-BPBI and CP-QPBI), comprising different proportions of hole-transporting carbazole and electron-transporting benzimidazole, were synthesized. Their thermal, physical, and electrochemical properties were characterized. The designated bulky star-shaped structures efficiently suppress the direct intramolecular interaction between the donor and acceptor subunits to give high triplet energies. Through computational studies, varying the ratio of hole- and electron-transporting moieties could significantly change the carrier injection/transporting abilities and charge balance properties of the host materials. Indeed, CP-QPBI with more benzimidazole units shows extremely enhanced current density at the same voltage when compared to mCP-BPBI. The operating voltage of solution-processed phosphorescent light-emitting diodes with CP-QPBI as host were dramatically reduced by ∼3 V compared with the similar devices of mCP-BPBI. At the same time, the power efficiencies were improved for 2-2.5 times at the corresponding voltage. Importantly, both blue and green devices maintain their high efficiencies even at brightness up to 1000 cd m(-2), which clearly demonstrates that the new strategy applied to improve electron-transporting ability and charge-balance property of the solution-processable host material by tuning the ratio of donor and acceptor unit is profitable.
Collapse
Affiliation(s)
- Xinxin Ban
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Wei Jiang
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Kaiyong Sun
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Xinyu Xie
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Lang Peng
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Hongshuang Dong
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Yueming Sun
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Bin Huang
- †School of Chemistry and Chemical Engineering, Southeast University, Nanjing, Jiangsu 211189, P. R. China
| | - Lian Duan
- ‡Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| | - Yong Qiu
- ‡Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| |
Collapse
|
3
|
Li H, Li C, Duan L, Qiu Y. Charge Transport in Amorphous Organic Semiconductors: Effects of Disorder, Carrier Density, Traps, and Scatters. Isr J Chem 2014. [DOI: 10.1002/ijch.201400057] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
4
|
Briggs EA, Besley NA, Robinson D. QM/MM excited state molecular dynamics and fluorescence spectroscopy of BODIPY. J Phys Chem A 2013; 117:2644-50. [PMID: 23461546 DOI: 10.1021/jp312229b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Absorption and emission spectra arising from the lowest energy transition in BODIPY have been simulated in the gas phase and water using a quantum mechanics/molecular mechanics (QM/MM) approach. Kohn-Sham density functional theory (DFT) is used to calculate both ground (So) and first excited (S1) states using the maximum overlap method to obtain the S1 state. This approach gives ground and excited state structures in good agreement with structures found using multiconfigurational perturbation theory (CASPT2). Application of a post-self-consistent field spin-purification relationship also yields transition energies in agreement with CASPT2 and available experimental data. Spectral bands were simulated using many structures taken from ab initio molecular dynamics simulations of the ground and first excited states. In these simulations, DFT is used for BODIPY, and in the condensed phase simulations the water molecules are treated classically. The resulting spectra show a blue shift of 0.3 eV in both absorption and emission bands in water compared to the gas phase. A Stokes shift of about 0.1 eV is predicted, and the width of the emission band in solution is significantly broader than the absorption band. These results are consistent with experimental data for BODIPY and closely related dyes, and demonstrate how both absorption and emission spectra in solution can be simulated using a quantum mechanical treatment of the electronic structure of the solute.
Collapse
Affiliation(s)
- Edward A Briggs
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | | | | |
Collapse
|
5
|
Bipolar charge transport property of N,N′-dicarbazolyl-1,4-dimethene-benzene: A study of the short range order model. CHINESE SCIENCE BULLETIN 2012. [DOI: 10.1007/s11434-012-5346-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|