Circularly Polarised Luminescence

Muller, Gilles

doi:10.1002/9781118682760.ch03

Cited by 28 publications

(14 citation statements)

References 129 publications

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“…[16][17][18][19][20][21] The largest dissymmetry factors, within the range 0.1 -1, have been observed for transitions within the 4f manifold of lanthanide (Ln) complexes. [22][23][24][25][26][27] Due to the weak crystal-field (CF), these transitions are nearly electric-dipole (ED) forbidden, but comparatively strongly magnetic-dipole (MD) allowed, reinforcing the magnitude of the values. For instance, a lum value of +1.38 was reported for the 7 1 ← 5 0 transition of the Europium(III) complex CsEu[(+)-hfbc] 4 .…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Gendron

Moore

Cador

et al. 2019

J. Chem. Theory Comput.

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Complete and restricted active space self-consistent field (CAS-/ RAS-SCF) wavefunction methods are applied for the calculation of circular dichroism (CD) and circularly polarized luminescence (CPL) of a series of molecules comprising four organic ketones, the chiral Cobalt(III) complex Λ-[Co(en) 3 ] 3+ and the Europium(III) complex [Eu(DPA) 3 ] 3 -. The abinitio results are in good agreement with the experimental data and previous results obtained with Kohn-Sham density functional theory in the case of the spin-allowed transitions. CD and CPL properties are calculated ab-initio for the first time for the spin-forbidden transitions of both a transition metal and a lanthanide complex. on a large set of organic compounds and on the spin-allowed transitions of some transition metal complexes. For instance, the experimental CD and CPL spectra of -camphorquinone and ( , )trans--hydrindanone were nicely reproduced when using TDDFT calculations with inclusion of the vibronic effects. 36 The results revealed that in both cases, the chiroptical properties arise from transitions between the and * orbitals of the carbonyl groups. Subsequently, Pecul and Ruud 37 applied TDDFT to a set of bicyclic ketones 38 and showed that the differences in sign and magnitude between abs and lum are essentially related to the structural differences between the ground and excited states. Based on a similar set of compounds, it was shown that equation-of-motion CCSD (EOM-CCSD) and TDDFT with the CAM-B3LYP functional provided similar accuracy for abs and lum , 39 while the popular B3LYP functional led to incorrect results in some of the emission properties.There is also a substantial body of research on the calculation of spin-allowed electronic CD spectra of transition metal complexes, where TDDFT remains the main computational tool. See, e.g., References 33, 40 and 41 for reviews and References 19, 42-50 for selected original studies. CPL calculations for transition metal complexes are scarce in comparison. A first attempt was made in 2008 by Coughlin et al. 21 with the use of TDDFT in combination with an approximate formulation of lum , in order to determine the chiroptical properties associated to the 0 ← 1 emission in a series of Iridium(III) complexes. Another attempt was made in 2013 with the use of multi-reference perturbative methods (CASSCF and CASPT2) on a cycloplatinated-[6]helicene compound. 19 Despite the ability of lanthanide complexes to exhibit the largest dissymmetry factors, no ab-initio calculations of CD or CPL properties have been performed yet. Theoretical work on lanthanide complexes has so far relied on CF models 51,52 in combination with the semiempirical Judd-Ofelt theory. 53,54 Recently, such CF based models were used to simulate the CD spectrum 55 and the Raman optical activity 56 of Ln-based compounds. TDDFT has been also used to calculate the CD spectrum of some Eu(III) and Yb(III) complexes, [57][58][59] but these studies focused on the UV-Vis part of the energy spectrum which corresponds mostly to intra-ligand ...

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Section: Introductionmentioning

confidence: 99%

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Gendron

Moore

Cador

et al. 2019

J. Chem. Theory Comput.

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“…Chiroptical spectroscopy is a powerful way to investigate the electronic properties of chiral systems. Circular dichroism (CD) and circularly polarized luminescence (CPL) are complementary tools to probe chirality in the ground state and excited state, respectively. , In particular, these chiroptical methods provide information on the magnetic transition dipole moment of an optical transition, a quantity that is otherwise practically inaccessible because of the inherent weakness of magnetic dipole transitions. CD and CPL have been observed on chiral semiconducting perovskites. − , However, CPL has been reported so far only at cryogenic temperatures , or in nanocrystal dispersions. , Other studies have investigated CPL in achiral perovskites by using selectively polarized photoexcitation. , CPL on chiral perovskite thin films at room temperature and using unpolarized photoexcitation has yet to be reported.…”

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confidence: 99%

Circularly Polarized Photoluminescence from Chiral Perovskite Thin Films at Room Temperature

et al. 2020

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Hybrid organic–inorganic perovskites allow the synthesis of high-quality, nanostructured semiconducting films via easily accessible solution-based techniques. This has allowed tremendous development in optoelectronic applications, primarily solar cells and light-emitting diodes. Allowed by the ease of access to nanostructure, chirality has recently been introduced in semiconducting perovskites as a promising way to obtain advanced control of charge and spin and for developing circularly polarized light sources. Circular polarization of photoluminescence (CPL) is a powerful tool to probe the electronic structure of materials. However, CPL in chiral perovskites has been scarcely investigated, and a study in bulk thin films and at room temperature is still missing. In this work, we fabricate bromine-based chiral perovskites by using a bulky chiral organic cation mixed with CsBr, resulting in Ruddlesden–Popper perovskite thin films. We measure CPL on these films at room temperature and, by using unpolarized photoexcitation, we record a degree of circular polarization of photoluminescence in the order of 10–3 and provide a full spectral characterization of CPL. Our results show that chirality is imparted on the electronic structure of the semiconductor; we hypothesize that the excess in polarization of emitted light originates from the charge in the photogenerated Wannier exciton describing an orbit in a symmetry-broken environment. Furthermore, our experiments allow the direct measurement of the magnetic dipole moment of the optical transition, which we estimate to be ≥0.1 μ B . Finally, we discuss the implications of our findings on the development of chiral semiconducting perovskites as sources of circularly polarized light.

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“…9,14 To evaluate the performance of CPL-active materials, the dissymmetry factor of luminescence (g lum ) is a critical index, which is given by the equation g lum = 2(I L − I R )/(I L + I R ), where I L and I R are the intensities of the pure left-and right-handed circularly polarized luminescence, respectively. 15,16 To date, high values of g lum of CPL could be achieved in metal complexes, 17,18 self-assembly gels, 19−21 photo upconversion, 22 etc. In addition, chiral nematic liquid crystalsotherwise referred to as cholesteric liquid crystals (CLCs)are self-organized helical superstructures that have one-dimensional long-range orientational order.…”

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confidence: 99%

“…Recently, chiroptical functional materials with CPL are attracting ever-increasing interests in photonic technology, such as three-dimensional (3D) optical imaging, − chiral sensors, , and photoelectric devices. − Generally, circularly polarized light is obtained from nonpolarized light by introducing filters of wire grid polarizer and quarter wave plate, but accompanying with great loss in brightness and outcoupling efficiency . Scientists have found that chirality can be introduced into fluorophores to obtain CPL. , To evaluate the performance of CPL-active materials, the dissymmetry factor of luminescence ( g lum ) is a critical index, which is given by the equation g lum = 2( I L – I R )/( I L + I R ), where I L and I R are the intensities of the pure left- and right-handed circularly polarized luminescence, respectively. , To date, high values of g lum of CPL could be achieved in metal complexes, , self-assembly gels, − photo upconversion, etc. In addition, chiral nematic liquid crystalsotherwise referred to as cholesteric liquid crystals (CLCs)are self-organized helical superstructures that have one-dimensional long-range orientational order.…”

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confidence: 99%

Rational Design of Circularly Polarized Luminescent Aggregation-Induced Emission Luminogens (AIEgens): Promoting the Dissymmetry Factor and Emission Efficiency Synchronously

et al. 2020

ACS Materials Lett.

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Development of circularly polarized luminescent (CPL) materials with strong emission and high dissymmetry factor of luminescence (g lum) is highly desirable. A series of CPL-active aggregation-induced emission luminogens (AIEgens) have been successfully constructed by incorporating AIEgen dicyanodistyrylbenzene (DCS) into chiral molecule cholesterol. Benefiting from its typical AIE characteristic, DCS allows emission efficiency up to 73.7% in a condensed state. Furthermore, cholesterol units ensure forming chiral liquid crystal in syntax, and increasing the g lum value of CPL from 7 × 10–4 for the amorphous state to 1.1 × 10–1 for the liquid crystal state. This approach paves a general avenue for addressing the major defect well: high g lum always suffers from suppression of emission efficiency.

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Circularly Polarised Luminescence

Cited by 28 publications

References 129 publications

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Circularly Polarized Photoluminescence from Chiral Perovskite Thin Films at Room Temperature

Rational Design of Circularly Polarized Luminescent Aggregation-Induced Emission Luminogens (AIEgens): Promoting the Dissymmetry Factor and Emission Efficiency Synchronously

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