OLED from solution-processed crystalline poly(triazine imide)

Crystalline semiconducting carbon nitrides are chemically and physically resilient, consist of earth abundant elements, and can be exfoliated into 2D atomically thin layers. In particular, poly(triazine imide) (PTI) is a highly crystalline semiconductor, and though no techniques exist to date that enable synthesis of macroscopic monolayers of PTI, it is possible to study it in thin layer device applications that are compatible with its polycrystalline, nanoscale morphology. In our study, we find that the by-product of conventional PTI synthesis is a C-C carbon rich phase that is detrimental for charge transport and photoluminescence. An optimised synthetic protocol yields a PTI material with an increased quantum yield, enabled photocurrent and electroluminescence. In addition, we report that protonation of the PTI structure happens preferentially at the pyridinic nitrogen atoms of the triazine (C3N3) rings, is accompanied by exfoliation of PTI layers, and contributes to increases in quantum yield and exciton lifetimes. This study describes structure-property relationships in PTI that link (i) the nature of defects, their formation, and how to avoid them with (ii) the optical and electronic performance of PTI. On the basis of our findings, we create an OLED prototype with PTI as the active, metal-free material, and we lay the foundations for device integration of solution-processable graphitic carbon nitride dispersions in semiconductor devices.

A review on the role of emerging revolutionary nanotechnology in forensic investigations

Due to the unique properties of nanoparticles, it has gained prominence in lots of fields with extensive research being carried around it. With lots of novel applications arising from this field, Forensic science seems to be one of the fast-growing fields in nano research applications. The growing and extensive use of nanotechnology being applied in forensic investigations is promising and could soon be the tipping point in the discipline. Applications mainly have been related to evidence identification and analysis in the broad major fields in Forensic Science such as single-crystalline semiconductor CdS nano slabs for explosives detection, functionalized TiO2 nanorods for organophosphorus chemical warfare agents in Forensic Chemistry, the use of Nanopowders for latent print visualization in Forensic physics and Gold nanoparticle protein nanopore for detection of single-stranded DNA in Forensic biology. Nanotechnology has also been employed in illegal drug detection in recent times. These and other applications of Nanotechnology provides prompt and precise results with reduced methods due to the limited instruments used for analyzing evidence as well as providing sensitive and selective ways of detecting evidence. As evidence is notable in forensic investigations, nanotechnology’s use in identifying and detecting these has potential in enhancing and providing efficient and rapid means for investigations and unravelling leads into crimes. This review emphasizes some disciplines in forensic sciences in which nanotechnology is having an impact, novel methods and newly developed instruments and also takes into account its challenges as well as perspectives into the future.

Model of stationary migration of free and hopping via acceptors holes in a crystalline semiconductor

In the diffusion-drift approximation, we have constructed a phenomenological theory of the coexisting migration of v-band holes and holes by means of hopping from hydrogen-like acceptors in the charge state (0) to acceptors in the charge state (−1). A p-type crystalline semiconductor is considered at a constant temperature, to which an external stationary electric field is applied. In the linear approximation, analytical expressions for the screening length of the static electric field and the length of the diffusion of v-band holes and the holes quasilocalized on acceptors are obtained for the first time. The presented relations, as special cases, contain well-known expressions. It is shown that the hopping migration of holes via acceptors leads to a decrease in the screening length and in the diffusion length.

Linearly polarized electroluminescence device in which the polarized plane can be rotated electrically using a chiral liquid crystalline semiconductor

The polarized plane of linearly polarized electroluminescence is rotated by DC bias application during a phase transition of a chiral liquid crystal phase.