Temperature dependent excited state dynamics in dual emissive CdSe nano-tetrapods

In hybrid perovskites, MAPbI3 and MAPbBr3 have been extensively studied for their optical and photovoltaic properties, but MAPbCl3 is significantly less investigated for its optical and photovoltaic properties due to its low photoluminescence quantum yield (PL QY) and a large band gap. However, the large band gap makes it a suitable host for doping transition metal ions to explore new optical properties. We synthesized nanocrystals (NCs) of MAPbCl3 doped with Mn2+ by simple ligand assisted reprecipitation method. The reaction temperature and Pb to Mn feed ratio were optimized by preparing a series of Mn2+-doped MAPbCl3 NCs. The prepared NCs show bright Mn2+ emission with ~13% PL QY suggesting an efficient energy transfer from host NCs to Mn2+. Since the large bandgap of MAPbCl3 precludes the possibility of investigating temperature dependent PL and lifetime measurements to understand the excited state dynamics, we carried out these experiments on Mn2+ doped MAPbCl2.7Br0.3 with the Br concentration adjusted to bring the bandgap of the alloyed system within the limits of the experimental technique. Our studies establish an anomalous behavior of Mn2+ PL emission in this host. These results reveal the origin of a temperature mediated energy transfer from exciton to Mn2+ and provides an understanding of the underlying mechanisms of PL properties of this new class of NCs.

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Temperature Dependent Anomalous Mn2+ Emission and Excited State Dynamics in Mn2+-Doped MAPbCl3-xBrx Nanocrystals

10.26434/chemrxiv.14095931.v1 ◽

2021 ◽

Author(s):

Bhushan Kore ◽

Shyamashis Das ◽

D. D. Sarma

Keyword(s):

Energy Transfer ◽

Excited State ◽

Band Gap ◽

Transition Metal Ions ◽

Anomalous Behavior ◽

Feed Ratio ◽

Temperature Dependent ◽

Efficient Energy Transfer ◽

Photovoltaic Properties ◽

Excited State Dynamics

In hybrid perovskites, MAPbI3 and MAPbBr3 have been extensively studied for their optical and photovoltaic properties, but MAPbCl3 is significantly less investigated for its optical and photovoltaic properties due to its low photoluminescence quantum yield (PL QY) and a large band gap. However, the large band gap makes it a suitable host for doping transition metal ions to explore new optical properties. We synthesized nanocrystals (NCs) of MAPbCl3 doped with Mn2+ by simple ligand assisted reprecipitation method. The reaction temperature and Pb to Mn feed ratio were optimized by preparing a series of Mn2+-doped MAPbCl3 NCs. The prepared NCs show bright Mn2+ emission with ~13% PL QY suggesting an efficient energy transfer from host NCs to Mn2+. Since the large bandgap of MAPbCl3 precludes the possibility of investigating temperature dependent PL and lifetime measurements to understand the excited state dynamics, we carried out these experiments on Mn2+ doped MAPbCl2.7Br0.3 with the Br concentration adjusted to bring the bandgap of the alloyed system within the limits of the experimental technique. Our studies establish an anomalous behavior of Mn2+ PL emission in this host. These results reveal the origin of a temperature mediated energy transfer from exciton to Mn2+ and provides an understanding of the underlying mechanisms of PL properties of this new class of NCs.

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Temperature-dependent anomalous Mn2+ emission and excited state dynamics in Mn2+-doped MAPbCl3-xBrx nanocrystals

Journal of Chemical Sciences ◽

10.1007/s12039-021-01919-0 ◽

2021 ◽

Vol 133 (3) ◽

Author(s):

Bhushan P Kore ◽

Shyamashis Das ◽

D D Sarma

Keyword(s):

Excited State ◽

Temperature Dependent ◽

Excited State Dynamics

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Temperature-Dependent Excited State Absorption in DNA and LNA Oligomers Supports an Emerging Model of Excited State Dynamics in DNA

The Open Spectroscopy Journal ◽

10.2174/1874383800903010043 ◽

2009 ◽

Vol 3 (1) ◽

pp. 43-51 ◽

Cited By ~ 2

Author(s):

Stanislav O. Konorov ◽

H. Georg Schulze ◽

Christopher J. Addison ◽

Charles A. Haynes ◽

Robin F.B. Turner ◽

...

Keyword(s):

Excited State ◽

Excited State Absorption ◽

Temperature Dependent ◽

Excited State Dynamics

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ULTRAFAST XUV SPECTROSCOPY TO PROBE CONICAL INTERSECTIONS AND EXCITED STATE DYNAMICS

Proceedings of the 74th International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2019.wk01 ◽

2019 ◽

Author(s):

Arvinder Sandhu

Keyword(s):

Excited State ◽

Conical Intersections ◽

Excited State Dynamics ◽

Xuv Spectroscopy

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Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

10.26434/chemrxiv.7860023 ◽

2019 ◽

Author(s):

Matthew M. Brister ◽

Carlos Crespo-Hernández

Keyword(s):

Excited State ◽

Excited States ◽

Ground State ◽

Transient Absorption ◽

Electronic Energy ◽

Transient Absorption Spectroscopy ◽

Electronic Relaxation ◽

Vibrationally Excited ◽

Excited State Dynamics ◽

Π State

Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived 1nOπ* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived 3ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.

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