Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
IR Absorption Frequency: Delocalization01:04

IR Absorption Frequency: Delocalization

Electron delocalization refers to the distribution of electrons across multiple atoms within a molecule rather than being confined to a single atom or bond. This phenomenon is common in systems with conjugated bonds—structures where alternating single and double bonds allow π-electrons to move freely across the network. The movement of electrons stabilizes the molecule and can affect various chemical properties, including vibrational frequencies observed in IR spectroscopy.
In IR spectroscopy,...
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
UV–Vis Spectroscopy of Conjugated Systems01:32

UV–Vis Spectroscopy of Conjugated Systems

Organic compounds with conjugated double bonds show strong absorption features in the UV–visible region of the electromagnetic spectrum attributed to π → π* electronic excitations. Generally, a UV–vis absorption spectrum is recorded as a plot of absorbance vs wavelength. The wavelength of maximum absorbance, which manifests as a peak in the absorption spectrum, is denoted as λmax.
One of the factors influencing λmax is the extent of conjugation in the...
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds01:14

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as annulenes. In...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Wavelength-selective bipolar photoresponse in CVD-grown β-Bi<sub>2</sub>O<sub>3</sub> flakes for multi-logic functionality.

Nanoscale·2026
Same author

Tunable itinerant ferromagnetism in two-dimensional FePd<sub>2</sub>Te<sub>2</sub> hosting 1D spin chains.

Newton ((New York, N.Y.)·2026
Same author

Switchable Magnonic Crystals Based on Spin Crossover/CrSBr Heterostructures.

Advanced materials (Deerfield Beach, Fla.)·2026
Same author

Substituent-Controlled Design of Naphthalene Diimide-Based Materials Exhibiting Semiconducting Behavior.

Chemistry (Weinheim an der Bergstrasse, Germany)·2026
Same author

Design and Experimental Realization of Ultra-High Green Index Electromagnetic Interference Shields With Opposing Magnetic and Conductivity Gradients.

Small (Weinheim an der Bergstrasse, Germany)·2026
Same author

Ultralow Energy Optoelectronic Synapse Using Halide Perovskite/Organic Semiconductor Heterostructure for Neuromorphic Computing, Optical Logic and Wireless Communication.

ACS applied materials & interfaces·2026

Related Experiment Video

Updated: Jun 17, 2026

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering
06:16

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

Published on: December 21, 2017

Exciton delocalization and optical synaptic functionality in conjugated polymer-In2Se3 heterostructures.

Md Saifuddin1, Shantanu Dhara2, Sourav Dey1

  • 1Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039, India. giri@iitg.ac.in.

Nanoscale Horizons
|June 16, 2026
PubMed
Summary
This summary is machine-generated.

Organic-inorganic heterostructures (OIHs) exhibit varied photoresponses. This study links polymer molecular structure and exciton delocalization to OIH photoresponse times and synaptic behavior, advancing neuromorphic device development.

More Related Videos

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications
08:06

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

Published on: June 2, 2017

Related Experiment Videos

Last Updated: Jun 17, 2026

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering
06:16

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

Published on: December 21, 2017

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications
08:06

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

Published on: June 2, 2017

Area of Science:

  • Materials Science
  • Organic Electronics
  • Nanotechnology

Background:

  • Conflicting photoresponse results in organic-inorganic heterostructures (OIHs) highlight the need to understand molecular structure's impact.
  • The influence of organic layer molecular structure and excitonic coupling on OIH photoresponse times remains unclear.

Purpose of the Study:

  • To investigate how the molecular structure and exciton delocalization of conjugated polymers affect the photoresponse times and synaptic properties of OIHs.
  • To elucidate the relationship between material properties, exciton dynamics, and charge-transfer pathways in OIH devices for neuromorphic applications.

Main Methods:

  • Fabrication of OIHs using poly(3-alkylthiophene) (P3AT) polymers (P3DDT, P3HT) and indium selenide (In2Se3).
  • Characterization of photoresponse times and synaptic properties (short-term, long-term memory, learning behavior).
  • Artificial neural network simulation for handwritten digit recognition using OIH synapse models.

Main Results:

  • P3DDT (low crystallinity, poor exciton delocalization) showed a fast photoresponse.
  • P3HT (ordered crystallites, pronounced exciton delocalization) exhibited slower photocurrent rise and photomemory effects.
  • P3HT/In2Se3 demonstrated synaptic properties, and an artificial neural network achieved 88% MNIST recognition accuracy.

Conclusions:

  • Exciton delocalization in conjugated polymers is a key factor determining OIH optical response times.
  • OIHs display promising synaptic properties for neuromorphic computing.
  • This research provides insights into OIH charge-transfer dynamics, enabling the design of advanced neuromorphic devices.