Visibly opaque but near-infrared (NIR)-transparent materials are an essential component for night-vision photography, security imaging, and forensic applications. Herein, the development of a novel supramolecular black dye from a diketopyrrolopyrrole (DPP)-based low-molecular-weight organogelator is described. In the solution state, the monomer of DPP-Amide exhibits a deep green color with a broad absorption in the visible region due to firm intramolecular charge transfer from the donor to the acceptor unit. Interestingly, due to the synergistic effect of H-bonding and π-stacking, DPP-Amide can form a black organogel in toluene with complete spectral coverage from 300 to 800 nm, and transmits beyond 850 nm. In the gel state, complete visible-spectrum coverage is achieved due to the simultaneous formation of both H- and J-type aggregates, which is confirmed via absorption studies. To create a free-standing NIR-transmitting elastomeric black filter, nanoscopic molecular aggregates of DPP-Amide (0.15 wt%) are embedded into a poly(dimethylsiloxane) matrix. This nanocomposite possesses high NIR transparency with good thermal and photostability for practical applications. Finally, the use of the developed material for NIR photography, security, and forensic-related applications is demonstrated.

Self-assembly is a viable approach to create soft functional materials with architectural diversity and property variations. Among the large number of different chromophores used, borondipyrromethene (Bodipy) dyes find a unique space because of their promising photophysical properties such as high molar absorptivity, fluorescent quantum yield and excellent photostability along with the associated synthetic ease. Recently, research on Bodipy dyes has experienced a surge of activities in view of favorable self-assembling properties. In this review, recent developments in self-assembled Bodipy dyes and their significance in various applications are discussed.

Surface of a particle is inevitably charged. When the particle is surrounded by a fluid a potential difference arises between the surface and bulk, called zeta potential (ζ) which controls many interfacial properties of the particle involving in suspension, emulsion, colloid etc. Many phenomena happening around us have at least one step that passes through an interface. Thus, the application of ζ is practically uncountable. Discovered in late 19th century, almost past 120 years, the application of ζ has emerged in many areas to meet the fruitful need of mankind. However, to the best of our knowledge, there is no report disclosed citing the applications at one place as a ready tool for the readers. The present review accumulates extensive survey of literature, bringing out various aspects of ζ in chemistry, engineering, biology, material, and environmental sciences. A brief theoretical background mentioning the principle and practical applications were focused.