Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Efficient photon upconversion at an organic semiconductor interface

Fig. 1 (a) Schematic illustrations of the conventional UC mechanism in films, and chemical structure of conventional sensitizer. (b) Schematic illustrations of the novel UC mechanism at the organic semiconductor interface. (c) Chemical structures of sensitizer and emitter of the novel UC systems.

CREDIT
NINS/IMS
Fig. 1 (a) Schematic illustrations of the conventional UC mechanism in films, and chemical structure of conventional sensitizer. (b) Schematic illustrations of the novel UC mechanism at the organic semiconductor interface. (c) Chemical structures of sensitizer and emitter of the novel UC systems. CREDIT NINS/IMS

Abstract:
Photon upconversion (UC) is a process in which a material increases the energy of incident photons, resulting in the emission of photons with higher energies. The potential applications of UC include the recovery of wasted low-energy photons in photovoltaics and photocatalysis. In addition, near-infrared (NIR) to-visible UC, offering the advantage of high penetration in living tissues, is desired for biosensing, optogenetics, and photodynamic therapy. The conventional UC system relies on a triplet formation from an absorbed photon by intersystem crossing (ISC), which is typically facilitated by heavy-atom effect in a sensitizer molecule (Fig. 1a). The two triplet excitons form high energy one singlet by an annihilation process. Finally, the UC emission occurs from an emitter molecule. However, the conventional solid-state UC is still inefficient, exhibiting a highest external quantum efficiency (EQE) of less than 0.1%, which remains the greatest challenge inhibiting its real-life applications.

Efficient photon upconversion at an organic semiconductor interface

Tokyo, Japan | Posted on November 19th, 2021

Group of Assistant Professor Seiichiro Izawa and Professor Masahiro Hiramoto at Institute for Molecular Science in Japan report that novel UC systems with heterojunctions of bilayer films of organic semiconductors (Fig. 1b). The mechanism of the first step involved in the novel UC relies on the charge separation at the sensitizer/emitter interface, thereby converting the photoexcited sensitizer singlet to free charges. This process is the same as the photoconversion at the electron donor/acceptor interface in organic photovoltaics. Subsequently, the free charges recombine to form the triplet at the interface. The UC emission is observable after the triplet-triplet annihilation. The sensitizer/emitter molecules used in the novel UC system (Fig. 1c) do not contain heavy atoms because the mechanism does not rely on ISC. According to the proposed mechanism, the entire pure sensitizer layer can absorb the incident light and contribute to the UC process. As a result, the solid-state UC system is achieved with the EQE of two orders of magnitude higher than those of the conventional systems, with an irradiation intensity about 100 mW/cm2, which is similar with standard solar fluence. The efficient UC enabled a demonstration of bright yellow emission on a flexible thin film by a NIR light-emitting diode excitation (Fig. 2). The novel UC system does not need strong laser excitation and the expensive platinum-group metals, rare-earth metals, or toxic elements. The finding leads to important applications of UC in flexible solar cells, bioimaging, and optogenetics.

####

For more information, please click here

Contacts:
Hayao KIMURA
National Institutes of Natural Sciences

Office: 81-354-251-890
Expert Contact

Seiichiro Izawa
Institute for Molecular Science

Office: 81-564-59-5537

Copyright © National Institutes of Natural Sciences

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

ARTICLE TITLE

Related News Press

News and information

Biology’s hardest working pigments and ‘MOFs’ might just save the climate: A range of processes that currently depend on fossil fuels but are really hard to electrify will depend on the development of genuinely clean fuels, and for that to happen, much more efficient catalysts wi July 22nd, 2022

Generating power where seawater and river water meet July 22nd, 2022

First electric nanomotor made from DNA material: Synthetic rotary motors at the nanoscale perform mechanical work July 22nd, 2022

At the water’s edge: Self-assembling 2D materials at a liquid–liquid interface: Scientists find a simple way to produce heterolayer coordination nanosheets, expanding the diversity of 2D materials July 22nd, 2022

Organic Electronics

University of Houston research allows for 3D printing of 'organic electronics' Micro-scale organic electronics for use in bioelectronics via multiphoton 3D printers June 24th, 2022

Flexing the power of a conductive polymer: A new material holds promise for the next generation of organic electronics June 24th, 2022

‘Fruitcake’ structure observed in organic polymers June 3rd, 2022

The future of data storage is double-helical, research indicates: The Information Age needs a new data storage powerhouse. With an expanded molecular alphabet and a 21st century twist, DNA may just fit the bill. March 4th, 2022

Possible Futures

Biology’s hardest working pigments and ‘MOFs’ might just save the climate: A range of processes that currently depend on fossil fuels but are really hard to electrify will depend on the development of genuinely clean fuels, and for that to happen, much more efficient catalysts wi July 22nd, 2022

Generating power where seawater and river water meet July 22nd, 2022

First electric nanomotor made from DNA material: Synthetic rotary motors at the nanoscale perform mechanical work July 22nd, 2022

At the water’s edge: Self-assembling 2D materials at a liquid–liquid interface: Scientists find a simple way to produce heterolayer coordination nanosheets, expanding the diversity of 2D materials July 22nd, 2022

Chip Technology

The best semiconductor of them all? Researchers have found a material that can perform much better than silicon. The next step is finding practical and economic ways to make it July 22nd, 2022

Buckyballs on gold are less exotic than graphene July 22nd, 2022

Quantum computer works with more than zero and one: Quantum digits unlock more computational power with fewer quantum particles July 22nd, 2022

At the water’s edge: Self-assembling 2D materials at a liquid–liquid interface: Scientists find a simple way to produce heterolayer coordination nanosheets, expanding the diversity of 2D materials July 22nd, 2022

Optical computing/Photonic computing

At the water’s edge: Self-assembling 2D materials at a liquid–liquid interface: Scientists find a simple way to produce heterolayer coordination nanosheets, expanding the diversity of 2D materials July 22nd, 2022

Rensselaer researchers learn to control electron spin at room temperature to make devices more efficient and faster: Electron spin, rather than charge, holds the key July 15th, 2022

Deep-ultraviolet nonlinear optical crystals: Concept development and materials discovery July 8th, 2022

Photoinduced large polaron transport and dynamics in organic-inorganic hybrid lead halide perovskite with terahertz probes July 8th, 2022

Discoveries

HKU physicists found signatures of highly entangled quantum matter July 22nd, 2022

How different cancer cells respond to drug-delivering nanoparticles: The findings of a large-scale screen could help researchers design nanoparticles that target specific types of cancer July 22nd, 2022

The best semiconductor of them all? Researchers have found a material that can perform much better than silicon. The next step is finding practical and economic ways to make it July 22nd, 2022

Buckyballs on gold are less exotic than graphene July 22nd, 2022

Announcements

Quantum computer works with more than zero and one: Quantum digits unlock more computational power with fewer quantum particles July 22nd, 2022

Biology’s hardest working pigments and ‘MOFs’ might just save the climate: A range of processes that currently depend on fossil fuels but are really hard to electrify will depend on the development of genuinely clean fuels, and for that to happen, much more efficient catalysts wi July 22nd, 2022

Generating power where seawater and river water meet July 22nd, 2022

First electric nanomotor made from DNA material: Synthetic rotary motors at the nanoscale perform mechanical work July 22nd, 2022

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Buckyballs on gold are less exotic than graphene July 22nd, 2022

Quantum computer works with more than zero and one: Quantum digits unlock more computational power with fewer quantum particles July 22nd, 2022

Biology’s hardest working pigments and ‘MOFs’ might just save the climate: A range of processes that currently depend on fossil fuels but are really hard to electrify will depend on the development of genuinely clean fuels, and for that to happen, much more efficient catalysts wi July 22nd, 2022

Generating power where seawater and river water meet July 22nd, 2022

Photonics/Optics/Lasers

‘Life-like’ lasers can self-organise, adapt their structure, and cooperate July 15th, 2022

Electrically driven single microwire-based single-mode microlaser July 8th, 2022

Deep-ultraviolet nonlinear optical crystals: Concept development and materials discovery July 8th, 2022

Photon-controlled diode: an optoelectronic device with a new signal processing behavior July 1st, 2022

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project