Context: Recently, Indian scientists have found a new process for synthesizing crystalline rubrene for the development of optoelectronic devices and also for preparation of Electronic Skin (E-Skin).
Key Points

• Scientists at the Institute of Advanced Study in Science and Technology (IASST) have found a new process for synthesizing crystalline rubrene, a polycyclic aromatic hydrocarbon-based thin film.
• This can be useful for the development of optoelectronic devices and also for preparation of Electronic Skin (E-Skin).
• The new synthesis is a water-free, solvent-free, environmentally friendly one-step plasma process.
• The resultant crystalline rubrene based film demonstrated optoelectronic properties.
• A highly uniform pin-hole-free thin film, that is useful for fabrication of high-end devices, can be deposited by this process.
• IASST is an autonomous institute of the Department of Science & Technology.

About Crystalline Rubrene

• Crystalline rubrene is a polycyclic aromatic hydrocarbon-based thin film.
• It is a water-free, solvent-free, environmentally friendly one-step plasma process.
• It demonstrated optoelectronic properties (which detect and control light).
• A highly uniform pin-hole-free thin film can be deposited by this process, which is useful for the fabrication of high-end devices.

Its Working principle

• Devices made of pyro-electric materials (that generate electric charge when they are heated or cooled) and piezo-electric materials (that generate electric charge under the effect of mechanical pressure), can help detect change in temperature and pressure.
• Pyro-electric materials also show pyro-phototronic effect where pyro-electricity is associated with the change in temperature of a material when it absorbs photons.
• Pyro-electric infrared detectors are well known for application in infrared sensing for space research, defense, remote sensing, and household appliances.

Principle application: Human Skin

• These kinds of materials are available in biological systems such as – human skin, plant cellulose leading to their significance in the understanding of basic science of biological systems and also in their huge application prospect.
• The rubrene crystal has a thin amorphous oxide layer formed over the crystalline film.
• This induces surface layer polarization effect leading to pyro-phototronic effect.

Significance of the research

• Since last few years, scientists from around the world are working on the synthesis of organic materials for electronic applications.
• The conventional process for synthesis of organic electronic materials based on chemical processes provides very good quality materials, but the stability of the materials is not very good, and it requires use of solvents.
• Moreover, multiple steps are required for material synthesis and film deposition.

Applications

• This novel process developed by the Indian team is useful for developing advanced optoelectronic devices and preparation of Electronic Skin (E-Skin).
• It may prove to be useful tool for laboratory simulation of different biological systems for probing the organization and dynamics of those systems.

About Optoelectronics

• Optoelectronics is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics.
• In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. 
• Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation.