Vol.:(0123456789) Optical and Quantum Electronics ( 2020) 52:28 https://doi.org/10.1007/s11082-019-2148-6 1 3 Synthesis and devices characterization of pyrazolo[4,3‑b] pyridine derivatives containing methoxy and hydroxy phenyl groups E. M. El‑Menyawy 1  · I. T. Zedan 2  · H. H. Nawar 3 Received: 12 June 2019 / Accepted: 7 December 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Two pyrazolo[4,3-b] pyridine derivatives namely; 2,3-dihydro-6-(4-methoxyphenyl)-1-me- thyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L1) and 2,3-dihydro-6-(4- hydroxyphenyl)-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L2) were prepared. The thermal analysis showed that the L1 is stable up to 266 °C, whereas L2 is stable up to 376 °C. The L1 and L2 powders were found to have polycrystalline structure in which their lattice parameters and Miller indices were determined. Thin flms of L1 and L2 were deposited by thermal evaporation technique. The absorption spectra of the flms were measured, from which the optical band gap of L1 and L2 flms was estimated as 2.72 and 2.83 eV, respectively. Two devices based on the flms of both materials, independently, were deposited onto p-Si single crystal substrates, were fabricated and showed rectifcation behavior. The current density–voltage (J–V) characteristics of both devices were analyzed in which the diode parameters were determined. The device based on L1 and L2 showed ideality factor of 2.73 and 3.5, respectively. Under illumination condition, the device based on L2 showed photovoltaic properties in which the open circuit voltage and short circuit current were measured as a function of light intensity. Keywords Organic materials · Structural properties · Optical absorption · Diodes 1 Introduction Organic materials are an attractive class owing to extraordinary fascinating electronic and optoelectronic properties and fexible processibility. They are promising alternatives to expensive inorganic materials. They fnd potential applications in large number of felds * E. M. El-Menyawy emad_elmenyawy@yahoo.com 1 Solid State Electronics Laboratory, Solid State Physics Department, Physics Research Division, National Research Centre, 33 El-Bohouth St., Dokki, Giza 12622, Egypt 2 Renewable Energy Science and Engineering Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University, Beni-Suef 62511, Egypt 3 Department of Chemistry, Faculty of Education, Al-Zintan University, Zintan, Libya