Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Porphyrin based hole transport layers for enhanced charge transport and stability in perovskite solar cells

Abstract: We have synthesized 5, 10, 15, 20-tetrakis {4-[N, N-di(4-methoxylphenyl) amino-phenyl]-porphyrin (Po) and its cobalt complex cobalt–porphyrin (CoP) hole-transport materials for efficient perovskite solar cells. Both Po and CoP exhibit excellent hole mobility and favorable energetic alignment with perovskite for hole extraction. Our results clearly show that incorporation of cobalt atom into Po boosts the power conversion efficiency up to 16.9%, which is 14% higher than without cobalt atom. CoP based devices exhibit better stability than Po devices. The perovskite layers that are deposited on top of CoP exhibit better crystallinity compared to Po, which are supported by the X-ray diffraction and morphological studies. These results are further evident from time-resolved photoluminescence.

Characterization of electrospun polyurethane/polyacrylonitrile nanofiber for protective textiles

Abstract: A system of polyurethane (PU) and polyacrylonitrile (PAN) with a polymer composition of 60:40 electrospun nanofibrous web has been developed as barriers to pesticides liquid (Dimethoate) penetration in protective clothing systems for agricultural workers. Barrier performance of different polymer compositions of PU and PAN layered systems has been evaluated with different areal densities of electrospun web ranging from 0.5 to 3 g/m2. This was done to improve the barrier performance of a nanofiber against a pesticide liquid. In this process, an ultra-thin layer of PU and PAN has been taken in the ratio of 60:40 and its top it is coated with polyvinylidene fluoride (PVDF). Application of PU and PAN web with PVDF and PU has significantly improved its effectiveness which has been measured when accessing the overall comfort performance of a nanofiber which includes parameters like air permeability and water vapor transmission within a layered system. Further, it is observed that the electrospun areal density has been altered due to the effect of air permeability and because of the penetration of the pesticide liquid. On other hand, the polymer compositions also affect the air permeability and rate of penetration of pesticides. It was observed that the electrospun web area has a massive impact on a web area density which reduces a pore size distribution when web area increases. Increasing the percentage of polyacrylonitrile with thermoplastic polyurethane the penetration is reduced without affecting the moisture vapor transition and which had a significant effect on air permeability. Hence PU and PAN along with PVDF nanofibrous mat have a prospective application in agro-textile industries.