Monthly Archives: August 2023

Preserving IoT Battery Life

At MIT, researchers have built a wake-up receiver for IoT devices. The receiver uses terahertz waves to communicate, making the chip more than ten times smaller than contemporary devices. The receiver also includes authentication that helps protect it from certain types of attacks. The low power consumption of the chip means it can help preserve battery life in robots or tiny sensors.

The current trend is towards developing ever-smaller devices for IoT or the Internet of Things. For instance, sensors can be smaller than a fingertip, capable of making any object trackable. Most of these tiny sensors, however, have even tinier batteries that are nearly impossible to replace. Therefore, engineers need to incorporate a wake-up device in these sensors. It keeps the device in a low-power sleep mode when not operating, thereby preserving battery life. The new device from MIT is capable of protecting the device from certain attacks that could drain its battery rather quickly.

The present generation of wake-up receivers is typical of the centimeter scale. This is because their antennas need to be proportional to the length of the radio waves they use for communicating. On the other hand, the MIT team utilized the terahertz wave for the receiver. As these waves are about one-tenth the length of regular radio waves, they could design the chip to be barely greater than a square millimeter.

It is possible to incorporate the wake-up receiver into microbots for monitoring environmental changes in locations that are either hazardous or too small for other robots to reach. As the device operates on terahertz frequencies, it is possible to use them in emerging applications like radio networks that operate as field-deployable swarms for collecting localized data.

Using terahertz frequencies, the researchers could make antennas the size of a few hundred micrometers on either side. The implication of such small-size antennas is that it is possible to integrate them on the chip, thereby creating a totally integrated solution. Ultimately, the researchers could build a wake-up receiver tiny enough to attach to tiny radios or sensors.

On the electromagnetic spectrum, terahertz waves exist between infrared light and microwaves. At very high frequencies, they travel much quicker than radio waves can. Terahertz waves, also known as pencil beams, travel in a rather direct path as compared to other signals, making them more secure.

However, terahertz receivers often multiply their signal by another signal so that they can alter their frequency. This process is termed frequency mixing or modulation, and it consumes a huge amount of power. The researchers at MIT used a pair of tiny transistors as antennas for detecting terahertz waves. This method of detecting consumes very little power, as it does not involve frequency mixing.

Even when they placed both antennas on the chip, the MIT wake-up chip was only 1.54 square millimeters and used only 3 microwatts to operate. The presence of two antennas maximizes its performance and makes it more sensitive to receiving signals. Once it detects the terahertz signal, it converts the analog signal into digital data for processing. The received signal contains a token, which, if it matches the wake-up receiver’s token, will activate the device.

In-Circuit Monitors for Electronic Devices

During a chip’s lifetime, there can be a wide variety of issues cropping up. Engineers are using sensors that can address them. As the semiconductor ecosystem touches a wide application space, sensors, and in-circuit monitors are playing an increasing role in managing the silicon lifecycle, thereby improving its resiliency and reliability.

Engineers are expecting a drastic improvement in the reliability of electronic devices with the addition of these sensors and in-circuit monitors. These expectations are due to a combination of sensor placements in true system-level design, in- and on-chip monitors, and an improvement in data analysis.

In the future, with engineers placing more monitors and sensors at strategic locations for collecting data, the combination, and analysis of this data is likely to increase tremendously. In addition, this will lead to a much more detailed understanding of what goes wrong in real time in the life of a semiconductor. Important to note, this is likely to open the door to recovery schemes for keeping devices functioning until they are due for replacement or repair.

All of the above depends on the complexity of the product. Although some regulatory standards for miniaturization are under study, the complexity of the product drives the use of sensors and in-circuit monitors. With consumers wanting greater capabilities in their hands, the requirement is going to increase substantially.

Although users were not interested earlier in concepts like resilience, predictability, and observability, things are changing fast. Chip architects are paying more attention to how systems and devices behave over time, including issues such as silent data corruption. Where earlier, it was hard to articulate the business reasons for such inclusion, chip architects are realizing there are missing pieces. While it is still a tussle between the why and how much, the realization is dawning that it is impossible to have all the computing resources or complex monitors-on-chip that can tackle all scenarios. Especially when such additions need real estate and power to function.

Designers are beginning to realize that advanced design techniques, in conjunction with manufacturing complexities and the latest process nodes, are leading to new challenges. These challenges appear as variable power consumption and affect the useful life of the semiconductor. The power consumption pattern and performance characteristics of a chip change as it travels along the silicon value chain. The variation starts with the pre-silicon design, moving on to new-product bring-up, to system integration, and finally, to its in-field usage.

Monitoring the way a chip degrades over time, can throw light on many types of semiconductor failures, especially with BTI or bias temperature instability. Using in-circuit monitors, it is now possible to measure areas that show performance and power degradation, on-die temperature variations, and workload stress, and monitor die-to-die interconnects for heterogeneous designs. Mission-critical systems define specifications such as safety and reliability as the key differentiating parameters. Moreover, with device functionality degrading over time, it is necessary to evolve tests that include lifetime operation as well.

The industry is now widely adopting an approach that includes more and more sensors and in-circuit monitors for electronic devices to monitor the most prominent slack paths. 

Wireless Chips for Internet of Things

TI® or Texas Instruments® has announced a new family of companion integrated circuits for SimpleLink®. According to TI®, these offer BLE or Bluetooth 5.3 Low Energy and Wi-Fi 6. The specialty of these chips is they provide connectivity in any type of environment, even when the temperature is over 220 °F (104.44 °C).

Industrial designs such as electric vehicle charging systems operating in the outdoors and sometimes hard-to-access environments is a challenging and expensive options for designers. Under such circumstances, the new SimpleLink® family of Wi-Fi devices from TI® is significantly simpler to install, and more affordable to implement, than ever before.

The SimpleLink® family consists of two chips, differentiated by their functionality. These are the CC3300 and the CC3301. While the lower-cost CC3300 offers Wi-Fi 6 connectivity alone, the other chip, the CC3301 adds the BLE or Bluetooth 5.3 Low Energy support. Both the ICs require pairing with a host microcontroller. This is a departure from TI®’s earlier SimpleLink® designs that combine a microcontroller and the radio. Significantly, there is no vendor tie-in, as both chips can work seamlessly with many types of controllers and processors from TI® and brands other than TI® that support real-time or Linux operating systems.

TI® is offering the devices in a QFN or quad flat no-lead package. Later in the year, TI® plans on introducing pin-compatible CC3xx variants that will add dual-band Wi-Fi connectivity, like 2.4 GHz and 5 GHz. At present, TI®® is also offering the BP-CC3301, an evaluation board.

With a SimpleLink® CC3301, it is easy to add BLE and Wi-Fi 6 connectivity to devices. It offers affordable, secure, and reliable connectivity in embedded applications. All it needs is a MCU host running RTOS, or a processor host running Linux. The BP-CC3301 is a test and development board from TI that the user can easily connect to any TI® Launchpad development kit or to a processor board, thereby enabling rapid software development. 

The user can use the kit in three configurations. One, for MCU and RTOS evaluation they can use the BP-CC3301 and LaunchPad with the MCU like the LP-AM243 running TCP/IP. Two, for processor and Linux evaluation, they can use the BP-CC3301 along with the BP-CC33-BBB-ADAPT and the BEAGLE-BONE-BLACK. Third, for RF testing using PC Tools, they can use the BP-CC3301 and the LP-XDS110. Additionally, the user can also wire the BP-CC3301 to any other RTOS or Linux host board that is also running the TCP/IP stack.

The BP-CC3301 has many useful features. It offers a companion IC providing Wi-Fi 6 and BLE in a QFN package. It has a BoosterPack plug-in module header or a 2×20 pin stackable connector to connect to plug-in modules of BoosterPack or other TIR LaunchPad development kits. The development kit comes with an on-the-board chip antenna with an option for testing based on SMA/U.FL. The kit also provides an SWD type interface for RF testing and standalone operation.

TI® has designed the development kit to accept power from a connected LaunchPad® kit. However, some LaunchPad® kits cannot supply the peak current requirement when the Wi-Fi 6 is operating. In such cases, the user can provide additional power from the USB connector.

Clamp-On Energy Meters

Traditional energy meters are mostly inline, meaning, the meter is in series with the circuit whose energy consumption it is monitoring. However, there is another type of energy meter that clamps onto the pipeline it must monitor, rather than break into the pipeline. This is an ultrasonic alternative and is specifically useful for energy management and billing applications that commercial, domestic, district, or shared cooling and heating systems use. Obviously, the clamp-on energy meter offers several advantages over its traditional in-line counterpart, the most significant of them being easier installation, cost savings, and maintenance benefits.

For the efficient operation of new or existing buildings, it is necessary to identify the waste, optimize the use, and accurately monitor for billing the use of energy and water. Optimizing the consumption of water and energy is essential and crucial for any type of building, whether it is a housing or accommodation, school, hospital, condo, office block, or shopping center, in the private or public sector. Mostly, energy monitoring applications associate automatic meter readings with a third-party cloud provider, thereby allowing for ease of use and seamless integration. These new type of meters are also suitable or retrofitting older and traditional energy meters in existing buildings that mostly have limited drawings and old pipework.

Managing fluid consumption requires finding out what is flowing where. The clamp-on energy meters accomplish this very easily, as there is no need to drain down the system, shut it down, or cut into the existing pipework. Therefore, using clamp-on energy meters saves a lot of time and money when retrofitting existing buildings.

There are several benefits to using clamp-on energy meters. It is possible to clamp them on a wide range of pipes, and they provide cross-correlation flow measurement systems for accuracy. These meters come with an optional RS485 serial interface and a Modbus RTU slave. They feature a 1-MHz transducer that is powerful enough to measure through poor or old thick wall pipes and larger pipes.

These new energy meters are a clamp-on and non-invasive alternative to traditional in-line meter installation. They are simple to install, simply connect power, enter the inside diameter of the pipe, adjust the sensors, and finally, clamp it on the pipe. No special tools or skills are necessary. The installation provides dry servicing, minimum downtime, and maximum availability.

The non-invasive energy meters require little or no maintenance since they have no moving parts or sensors to wear out or require calibration. Therefore, they have a longer service life with very few repair requirements. Being generally less expensive for installing and maintaining than invasive meters, the non-invasive meters do not require cutting into pipes or installing additional sensors. As it is not necessary to cut into the pipe, the risk of leaks is very much reduced. This is especially important in applications where the fluid in the pipe is expensive or hazardous. Overall, non-invasive clamp-on energy meters are a cost-effective and effective solution for measuring the energy flow in a surprisingly wide range of applications.

These meters are very useful in various types of buildings, including residential buildings, schools, hospitals, and offices.

How is a Wire Harness Made?

Many sectors, including industrial and consumer electronics, continue to use wire harnesses, and their use is increasing continuously. Therefore, there is an urgent need to understand the process of manufacturing this vital component. Wire harnesses link different electrical or electronic modules to allow the complete system to work seamlessly.

Wire harness assemblies are a bunch of wires processed with a protective sheath. They may end in different types of terminations. Harnessing is important as it organizes the wires for easy implementation. Wire harnesses must not be confused with cable assemblies, which bind multiple covered wires with a protective covering, enabling them to work in harsh environments.

The use of wire harness assemblies results in several advantages. The organized wires optimize space while helping to improve assembly times. The harness helps in customizing the appliance to its bespoke needs. The protective covering on the wires improves equipment safety while improving the life of the wires. A variety of appliances use wire harnesses extensively. These include heavy equipment, panel displays, flight simulators, control panels, vehicles, and more.

The wire harness manufacturing process begins with design. Each product requires a custom-designed harness. It is imperative to choose each component of the wire harness carefully to achieve full functionality and life.

The primary requirement is the length of each wire in the harness. As the wire may require routing through the equipment, the length of individual wires in the bunch may differ. The length of the wires may also depend on their diameter, as thicker wires require more space to bend.

Each wire must also be considered for the maximum current it will carry. In a wire harness, some wires may carry power while some may carry low-frequency signals. They will require wires of different gauges.

Once the designer determines the length and gauge of each wire, they must concentrate on the wire terminations, which are necessary to connect each wire to its starting and ending points. This depends on the end termination of the two devices the wire will be joining. The terminations may use lugs, crimps, connectors, or something similar.

Once the wires are bunched together to form the harness, it will be difficult to identify them individually. Therefore, the designer will require some means of identifying individual wires in the bunch. Ferrules are a low-cost choice for this purpose. They are available in different diameters and individually marked with numbers and alphabets. By using the same combination of ferrules with numbers and alphabets on both ends of a wire, it becomes easy to identify the wire, even after bunching it with several others. However, this identification is only necessary if the operator will connect each wire individually. They are not necessary if the termination ends in a connector.

Next, wire harnesses may require a jig to form them into the final shape necessary for implementation in the system. Once the operator arranges or dresses the wire harness in the jig, they may require a means to bunch all the wires together. This may take different forms, like a plastic wire or sheath covering the full length of the wire harness.

What is Diode Biasing?

PCB assemblies often contain numerous components. The engineer designing the board selects these components individually, based on their function in the circuit. For a successful project, it is essential to understand the basic operation of these components individually, and in relation to one another. One such component is the diode.

A diode is a semiconductor device with a PN junction. It supports current flow in only the forward direction—from the anode to the cathode—and not in the reverse. However, to allow current flow in the forward direction, a diode must be given a particular voltage to overcome the bias in its PN junction. Diode biasing is the application of a DC voltage across the diode’s terminals for overcoming the PN junction bias.

It is possible to bias a diode in two ways—forward and reverse. When forward biased, the diode allows current flow from its anode to its cathode, provided the biasing voltage is greater than the PN junction bias. However, when reverse-biased, the biasing voltage cannot overcome the PN junction bias, and the diode blocks any current flow. Reverse biasing a diode is a convenient way for using it to convert alternating current to direct current. Proper use of forward and reverse biasing also allows other functions, such as electronic signal control.

Diodes are mostly germanium or silicon-based. A diode consists of a layer of P-type semiconductor material and another layer of an N-type semiconductor material joined together. The P-type material forms the anode terminal and the N-type material forms the cathode terminal of the diode.

When fabricating a diode, the manufacturer dopes the two layers differently. They dope one of the layers with boron or aluminum to make it P-type, which gives it a slightly positive charge. The P-type semiconductor, therefore, has a deficit of electrons or an abundance of holes. They dope the other layer with phosphorus or arsenic to give it a slightly negative charge and make it N-type. Therefore, the N-type semiconductor has an abundance of electrons.

At the junction of the P-type and N-type layers, electrons and holes combine to form a sort of neutral zone. Therefore, when a current must flow, a voltage bias is necessary to push the electrons and holes through this neutral zone. The neutral zone is less than a millimeter in thickness.

A forward bias pushes holes from the P-type layer, across the neutral zone, into the N-type layer. The forward bias reduces the width of the neutral zone to allow the current to flow. The forward bias necessary depends on the material of the diode. It is 0.7 VDC for silicon diodes and about 0.3 VDC for germanium diodes.

On the other hand, a reverse bias adds more electrons to the N-type layer and holes to the P-type layer. This increases the width of the neutral zone, making it impossible for current to flow across it.

Therefore, forward biasing allows current flow through the diode from the anode to the cathode, and reverse biasing prevents current flow. Even with forward biasing, there is no current flow until the voltage is able to overcome the PN junction bias.

Parylene Conformal Coatings for Electronics

Conformal coating on electronic assemblies protects sensitive components and copper tracks on circuit boards from the vagaries of the environment. Typical conformal coatings are epoxy-based, requiring a thick layer to be effective. Parylene conformal coatings, on the other hand, can be ultra-thin and pinhole-free as they are polymer based.

Parylene conformal coatings offer a number of high-value surface treatment properties. These include resistance to moisture and chemical ingress and an effective dielectric barrier. In addition, Parylene also offers excellent thermal conductivity, dry-film lubricity, and UV stability, very essential for electronic subsystems. These properties of Parylene conformal coatings make it an ideal choice for various applications in the fields of consumer electronics, medical electronics, transportation industry, and defense and aerospace industries.

Manufacturers of a unique polymer series use the generic name Parylene for their products. These variations or members of the Parylene family each offer their own, somewhat different properties of the coating. Parylene variants are commercially available, and they are Parylene N, C, D, HT, and ParyFree.

Parylene N or poly(para-xylene) is the basic member of the series. This is a totally linear and highly crystalline material. Being a primary dielectric, Parylene N exhibits a very low dissipation factor and high dielectric strength. It shows an exceptionally low dielectric constant, varying very little with frequency. It also exhibits substantially high crevice-penetrating ability, second only to Parylene HT.

The second commercially available member of the Parylene series is Parylene C, derived from the same raw material as Parylene N. The only difference from Parylene N is the substitution of a chlorine atom for an aromatic hydrogen atom. The useful combination of physical and electrical properties, in addition to very low permeability to corrosive gases and moisture, makes Parylene C useful as a conformal coating.

The third member of the Parylene series is Parylene D, also a derivative of the same raw material that produces Parylene N. The substitution of a chlorine atom for two aromatic hydrogen atoms differentiates Parylene D from Parylene N. Most properties of Parylene D are similar to those of Parylene C. However, Parylene D has the added ability for withstanding slightly higher use temperatures.

The newest addition to the Parylene family is Parylene HT, a commercially available variant. The difference from the other family members is in the replacement of the alpha hydrogen atom of the N dimer with fluorine. Parylene HT can withstand temperatures of 450 ℃, therefore suitable for high-temperature applications. It also has excellent long-term UV stability, a low coefficient of friction, and low dielectric constant. Among the four of the family above, Parylene HT shows the highest penetrating ability.

A unique member of the family series is ParyFree, and this is also the newest. The difference from Parylene N dimer is in the replacement of one or more hydrogen atoms with a non-halogenated substituent. Compared to other commercially available Parylenes, this halogen-free variant offers advanced barrier properties of Parylene C along with substantially improved mechanical and electrical properties. This allows ParyFree to offer robust protection against water, moisture, corrosive solvents, and gasses, as required by select industries.

Robots with Eyes and Brain

In the manufacturing industry, a huge transformation is taking place—machine vision—and it is growing at astronomical proportions. This includes all types of machine vision. For instance, the market is expecting 3D machine vision to double in size during the coming six years. As of now, this technology is proving to be a vital component in many modern solutions for automation.

Several factors contribute to the increasing adoption of this technology in manufacturing. While there is greater demand for automation solutions as the industry grapples with labor shortages, the cost of automation has decreased tremendously—sensors, cameras, robotics, and processing power are now substantially cheaper—enabling greater deployment.

Technological performance has also jumped up a notch higher, and machine vision systems now have the ability to process substantial amounts of information within a fraction of a second. Finally, machine learning algorithms and advanced artificial intelligence are transforming the data collected by machine vision even more versatile, allowing manufacturers to better realize the power from those solutions. Incorporated into automation solutions, machine vision is now producing better outcomes.

The vision system of a machine is basically made up of a number of disparate parts. These include the camera, lenses, sources of lighting, robotic movements, processing computers, application-specific software, and artificial intelligence algorithms.

While the camera forms the eyes of the system, machine vision can have several types of cameras depending on the application’s needs. An automated solution may have various cameras with different configurations.

For instance, there can be static cameras, for placing in fixed positions. These usually have a more bird’s eye view of the process, useful in applications where speed is imperative. On the other hand, dynamic cameras placed on the end of robotic arms can come much closer to the process, resulting in much higher accuracy and detailed capture.

Another important aspect of the vision system is its computing power. This is the brain of the system that helps the eyes (cameras) to do their work. Computation resources, coupled with machine learning algorithms, must not be confused with traditional machine vision applications. Companies offering machine vision capability also offer software libraries for implementation.

While manufacturers design their systems specifically for application users, others offer them targeted toward software programmers. Ultimately, the software provides the machine vision system with advanced capabilities offering a dramatic impact for manufacturers. Programs are available for control of tasks along with the ability to provide feedback from the line with valuable insights.

Machine vision-guided systems are gaining steam as a concept for replacing basic human capabilities. For instance, machine vision for assembly lines enables an increasing range of processes and applications.

Typical applications of machine vision include assembly processes for power tools, medical equipment, home appliances, and industrial assembly lines. Most assembly steps in the fabrication of electronic equipment can benefit from the use of machine vision, as it offers a substantial increase in the level of precision achieved.

For instance, machine vision improves inspection of component placement of tiny surface mount components on printed circuit boards before they go for soldering. It improves the line throughput, while not succumbing to fatigue as a human inspector would.

3D Printing and Electricity from Waste Heat

There are several techniques existing for recovering energy from waste heat. The typical approach is to use waste heat to generate electricity. Now 3-D printing methods are taking the lead to make devices that will convert waste heat into electricity.

UNIST is located in the largest industrial city of Ulsan in Korea. Engineers there have conducted breakthrough research. They have developed a new thermoelectric technology for producing power-generating tubes. The best part of their research is they can print the tubes using 3-D printing methods.

Most automobile and industrial exhaust gases generally go to waste. But they are usually hot. By generating electricity from these hot exhaust gases, it is possible to enhance the efficiency of fossil energy production techniques. For this, the most suitable method is to use thermoelectric or TE methods. However, this is not an easy task, as typical thermoelectric products that the traditional processes produce are neither cost-effective nor do they fulfill efficiency requirements. According to the researchers, exhaust pipes fall into this category.

Engineers addressed this inefficiency issue by creating a special type of exhaust pipe. They built it out of lead and tellurium and used 3-D printing techniques for creating it. According to the researchers, they created the ink for the 3-D printer by mixing metal particles with a glycerol solvent. This provided them with the necessary viscoelasticity necessary for the ink and gave the ink the necessary characteristics of elasticity and viscosity.

The tube printed with this ink offers a high thermoelectric performance between temperatures of 400 and 800 °C. Most exhaust gases from vehicles exhibit this range of temperatures.

The research was a joint venture between the Department of Mechanical Engineering, UNIST, and the Department of Materials Science and Engineering, UNIST.

With their computational and experimental findings, the researchers have demonstrated the efficacy of their 3-D printed TE tubes they made from PbTe for power generation from waste heat. Their design has proven to be a system-adaptive and high-performance thermoelectric generator.

The 3-D printed power-generating PbTe TE tubes are made of p-type material and n-type material, with insulating material separating them. The TE tube has a series of p-type PbTe tubes followed by an insulating tube, and an n-type tube repeating many times. One complete power-generating TE tube may have ten pairs of p-type and n-type PbTe tubes in series.

According to the lead researcher, this 3-D printed power-generating PbTe TE tube technology can efficiently convert waste heat escaping through factory chimneys into electricity. In fact, factory chimneys are the most common type of source of waste heat. The shape of the tube makes it very effective for collecting heat as compared to the conventional rectangular shape of present TE generators.

Using 3-D printing technology for producing thermoelectric materials overcomes the limitations that engineers typically face while using commercial materials. According to the researchers, other fields can also use the viscoelastic characteristics that 3-D printed materials offer. The publication Advanced Energy Material features this novel and innovative research in thermoelectric materials.

Nanomaterial for Improving LED Brightness and Efficiency

LEDs are a ubiquitous presence in our lives. They have replaced almost all forms of lighting devices we were using earlier, replacing incandescent lamps, fluorescent lamps, compact fluorescent lamps, mercury vapor lamps, and sodium vapor lamps. This has been possible primarily because of the efficiency and long life of LED lamps. Now there is new research to suggest ways to improve their efficiency and brightness further. This could lower their cost, leading to a further lowering of the cost of scientific tools and consumer goods.

A huge team of researchers, including engineers from the Academia Sinica in Taiwan, the SLAC National Accelerator Lab, Brookhaven, National Laboratory, Los Alamos, and the Center of Nanoscale Materials, Argonne, have managed to make stabilized perovskite nanocrystals. They will use these nanocrystals in LEDs to improve their brightness and stability substantially.

Perovskite crystals have a singular crystalline structure, giving them properties for absorbing and emitting light. This characteristic is helpful in making energy-efficient devices including gamma detectors, consumer devices, and solar cells.

Although scientists have long considered perovskite nanocrystals as a prime candidate material for LEDs, the unstable nature of the perovskites prevented them from actual implementation. The research team stabilized the crystals by embedding them in a porous structure of MOF or a framework of metal and organic substances.

Such an intriguing concept of stabilization has been accomplished earlier also. But scientists could demonstrate that only in powder form. Earlier attempts to create LEDs from perovskite nanocrystals failed as the nanocrystals degraded back to their bulk phase. This led to a loss of their nanocrystal advantages in building LEDs. In the bulk form, the perovskite is in the nanophase, and it behaves differently.

The team managed to solve the problem by creating the perovskite crystals in the emission layer in an LED, for the first time. They have demonstrated that it is possible to manufacture light-emitting diodes at a low cost with perovskite nanocrystals by embedding them in a framework of metal and organic substances. Embedding the perovskite nanocrystals in a MOF framework stabilizes them for the working conditions of the LED.

For making the MOF, the team used a framework of lead nodes as the metal precursor, and for the organic material, they used halide salts. The methylammonium bromide in the halide salts reacted with the lead in the framework, forming nanocrystals around the lead core, and trapping them in the matrix.

As the matrix isolates the nanocrystals, they cannot interact and degrade. The researchers used this method as a coating, as it is substantially cheaper than vacuum processing. Almost all inorganic LEDs in wide use today require vacuum processing.

The team claims it is possible to create bright red, green, and blue LEDs with the MOF-stabilized technique. According to them, it is also possible to create them in various shades of the three colors. They have demonstrated, for the first time, that by stabilizing perovskite nanocrystals in MOF, they can create bright and stable LEDs in a full range of colors. It is possible to create LEDs of different colors, and improve their color purity while enhancing their ability to generate light.