Heterostructure crystals could light the way to optical circuits

Striped glow sticks
Credit: Wiley-VCH

It may be possible to reach new levels of miniaturization, speed, and data processing with optical quantum computers, which use light to carry information. For this, we need materials that can absorb and transmit photons. In the journal Angewandte Chemie, Chinese scientists have introduced a new strategy for constructing photonic heterostructure crystals with tunable properties. Using a crystalline rod with stripes that fluoresce in different colors, they have developed a prototype of a logic gate.

The team led by Ze Chang and Xian-He Bu achieved success by using specially constructed (MOFs)—lattice-like structures made of metallic "nodes" bridged by organic ligands. These structures contain cage-like cavities that can hold other molecules as "guests". In this case, the guests and a part of the ligands integrated into the lattice are matched so that the guests can transfer electrons to the ligand molecule (charge transfer). Such systems tend to fluoresce. The color of the fluorescence for a given MOF depends on the type of guest.

A further advantage of MOF structures is that their crystallization occurs through the growth of layers onto a crystallization nucleus in one preferred direction. The researchers from Nankai University, Tianjin, the Collaborative Innovation Center of Chemical Science and Engineering, Tianjin and Institute of Chemistry Chinese Academy of Sciences, Beijing (China) were thus able to produce rod-shaped crystals. During the crystallization, they varied the types of guest molecule incorporated. This resulted in "striped" rods with separate domains that fluoresce differently. For example, they produced rods whose ends absorb UV and fluoresce blue-green, while the center absorbs visible green light and emits red light. Because they are in direct contact, energy can be transferred between the domains, and some of the blue-green photons can be transmitted to the center portion, thereby causing it to fluoresce red. Most importantly, these rods behave as light conductors, meaning that no matter which spot is irradiated, part of the fluorescence light is transported through the entire rod to its ends.

Based on this type of crystal, the researchers developed a prototype for a with two "entrances" and two "exits"; that is, locations where light can be stored or registered and red and/or blue-green signals generated, respectively. The researchers envision potential applications for their MOF crystals in components with integrated optical circuits, such as photonic diodes, on-chip signal processors, and optical logic gates.


Explore further

Microrods made of lanthanoid organic frameworks act as microscale optical waveguides

More information: Xiao-Ting Liu et al, Engineering Donor-Acceptor Heterostructure Metal-Organic Framework Crystals for Photonic Logic Computation, Angewandte Chemie International Edition (2019). DOI: 10.1002/anie.201906278
Provided by Wiley
Citation: Heterostructure crystals could light the way to optical circuits (2019, August 6) retrieved 24 August 2019 from https://phys.org/news/2019-08-heterostructure-crystals-optical-circuits.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
67 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more