Structural and Optical Analysis of Eu3+ Doped BiVO4 Nanophosphor by Combustion Method

2015 ◽  
Vol 752-753 ◽  
pp. 272-276 ◽  
Author(s):  
R.S. Yadav ◽  
Y. Dwivedi ◽  
S.B. Rai
Keyword(s):  
Excited State ◽  
Relaxation Process ◽  
Emission Intensity ◽  
Spectroscopic Analysis ◽  
Laser Excitation ◽  
Wide Spectrum ◽  
Combustion Method ◽  
Annealed Sample ◽  
Optical Analysis ◽  
Time Resolved

Present article report synthesis and spectroscopic analysis of BiVO4 nanophosphor doped with trivalent Eu ions. It was observed that BiVO4 nanocrystals shows higher yield in comparison with the as-made nanocrystals on 266 nm laser excitation. On 266 nm excitation, emission composed of red dominated wide spectrum in the range of 400-950 nm was reported. Emission intensity enhanced five times on annealed sample than the counterpart. Time resolved analysis explores significant alteration in excited state relaxation process due to annealing. Detailed photo physics involved to improve optical emissions has also been explained.

scholarly journals Time-Resolved Resonance Raman Spectroscopy of Excited-State Porphyrins

1999 ◽  
Vol 19 (1-4) ◽  
pp. 271-274 ◽  
Author(s):  
S. E. J. Bell ◽  
J. H. Rice ◽  
J. J. McGarvey ◽  
R. E. Hester ◽  
J. N. Moore ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Laser Excitation ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Laser Pulses ◽  
Significant Shift ◽  
Time Resolved ◽  
Two Component ◽  
Absorbance Difference

Time-resolved resonance Raman (TR3) and absorbance difference studies of the excited states of Cu(TPP) (TPP=5,10,15,20-tetraphenylporphyrin) have been carried out with < 10 ps times resolution in THF and pyridine solvents. In THF the distinctive transient Raman bands in the ν2 and ν4 regions, previously observed with ns laser pulses, grow in the first 55 ps before decaying in 100's of ps. The ∆A spectra also show biphasic decay. This behaviour is associated with attack by solvent on the 4-coordinate excited state to form the longer lived species observed in TR3 experiments.In pyridine two component decay is also observed but it is the shorter-lived species which gives the transient Raman bands seen previously with ns laser excitation. This state is different from that seen in THF. At 5 ps delay ν4 is broader than in the ground state and, more importantly, there is a significant shift in the two pyridine bands at ca. 1000 cm-1. This implies a significant involvement of the pyridine-based orbitals in the excited state.

scholarly journals The peak shift and evolution of upconversion luminescence from CsPbBr3nanocrystals under femtosecond laser excitation

RSC Advances ◽  
2017 ◽  
Vol 7 (57) ◽  
pp. 35757-35764 ◽  
Author(s):  
Qiuju Han ◽  
Wenzhi Wu ◽  
Weilong Liu ◽  
Yanqiang Yang
Keyword(s):  
Excited State ◽  
Femtosecond Laser ◽  
Laser Excitation ◽  
Upconversion Luminescence ◽  
Peak Shift ◽  
Peak Position ◽  
Red Shift ◽  
Time Resolved ◽  
Pl Spectrum

Compared with normal PL, a red shift of upconversion PL spectrum is observed. Time-resolved PL and TA spectroscopies show FWHM and peak position are changed at various times, which suggest the existence of more than single excited state.

Visualization and Manipulation of Molecular Motion in Solid State through Photo-Induced Clusteroluminescence

2019 ◽  
Author(s):  
Haoke Zhang ◽  
Lili Du ◽  
Lin Wang ◽  
Junkai Liu ◽  
Qing Wan ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Excited State ◽  
Solid State ◽  
Light Source ◽  
Molecular Motion ◽  
Molecular Machine ◽  
Conjugated Molecules ◽  
Time Resolved ◽  
Packing Structure ◽  
New Strategy

<p>Building molecular machine has long been a dream of scientists as it is expected to revolutionize many aspects of technology and medicine. Implementing the solid-state molecular motion is the prerequisite for a practical molecular machine. However, few works on solid-state molecular motion have been reported and it is almost impossible to “see” the motion even if it happens. Here the light-driven molecular motion in solid state is discovered in two non-conjugated molecules <i>s</i>-DPE and <i>s</i>-DPE-TM, resulting in the formation of excited-state though-space complex (ESTSC). Meanwhile, the newly formed ESTSC generates an abnormal visible emission which is termed as clusteroluminescence. Notably, the original packing structure can recover from ESTSC when the light source is removed. These processes have been confirmed by time-resolved spectroscopy and quantum mechanics calculation. This work provides a new strategy to manipulate and “see” solid-state molecular motion and gains new insights into the mechanistic picture of clusteroluminescence.<br></p>

Unveiling anharmonic coupling by means of excited state ab initio dynamics: application to diarylethene photoreactivity

2019 ◽  
Vol 21 (7) ◽  
pp. 3606-3614 ◽  
Author(s):  
Maria Gabriella Chiariello ◽  
Umberto Raucci ◽  
Federico Coppola ◽  
Nadia Rega
Keyword(s):  
Excited State ◽  
Ab Initio ◽  
Vibrational Analysis ◽  
Time Resolved ◽  
Anharmonic Coupling ◽  
New Time

We adopted excited state ab initio dynamics and a new time resolved vibrational analysis to unveil coupling between modes promoting photorelaxation.

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