Optical Materials 138 (2023) 113696 Available online 27 March 2023 0925-3467/© 2023 Elsevier B.V. All rights reserved. Research Article Silver doped ZnSnO 3 /SnO hybrid nanostructures as DSSC photoanodes: Charge injection dynamics, slow recombination kinetics and simulation studies M. Ani Melfa Roji a , P. Ram Kumar b, ** , X. Sahaya Shajan 1 , T. Ajith Bosco Raj a, * a Department of Electronics and Communication Engineering, PSN College of Engineering and Technology, Melathediyoor, Tirunelveli, 627 152, Tamilnadu, India b Department of Chemistry, Lord Jagannath College of Engineering and Technology, Nagercoil, Kanyakumari, 629 402, India A R T I C L E INFO Keywords: Dye sensitized solar cell Zinc stannate Silver-sensitization Semiconductors Absorption spectroscopy Electrochemical impedance spectroscopy ABSTRACT Sol-gel synthesis was used to develop a new hybrid photoanode material, a spherical zinc stannate/tin oxide nanorod named ZSTP. The subsequent step involves doping ZSTP with silver using a precursor called silver nitrate. The undoped sample was labelled as ZSTP, whereas silver-doped composites containing 1, 2, and 3 wt% silver were labelled as ZSTP-Ag1, ZSTP-Ag2 and ZSTP-Ag3 respectively. The pattern of powder X-ray diffraction (PXRD) with 2θ values of 26.52 and 33.84 confirms the orthorhombic structure of ZSTP and silver-doped samples. In the FT-IR spectra of the ZSTP and their silver-doped samples, the stretching frequency for Zn–O–Sn is observed at 1100 and 1464 cm  1 . In addition, the surface-adsorbed Ag peaks at 1384 cm  1 . The XPS spectra of ZSTP-Ag3 confirms the existence and structure of SnO and Ag. Examining the morphology with a scanning electron microscope (SEM) and transmission electron microscope (TEM) reveals a porous structure with adsorbed Ag on the surface. Doped silver appears as tiny spherical particles on the surfaces, whereas SnO nanorod zinc stannate appears as spherical particles in the TEM image. In-depth optical experiments were conducted to evaluate the characteristics of hybrid composites for DSSC applications. It was explored how the dye aggregates on the surface of silver-doped ZSTP. On the basis of the energy levels of their conductance bands, the electron transfer kinetics and energy transfer mechanism were predicted. Under a conventional one-sun illumination condition, the output photocurrent and photovoltage of these DSSC materials are evaluated. ZSTP-Ag3 offered the highest PCE at 1.38%. Due to the role of Ag2O in electron transfer, silver doped samples based devices offer a high FF (0.7) and steady photovoltage. Using the photovoltage decay curve, the recom- bination time (τ rec ) and rate (k rec ) were calculated to confirm a slower rate of recombination. Using simulated results, the overall performance of the DSSC is compared and validated. 1. Introduction Due to their useful invention, affordable manufacturing, and high light conversion efficiency, dye sensitized solar cells (DSSC) have received a lot of attention and have been quickly developed [1–4]. Dye sensitized solar cells have received a lot of interest from researchers as prospective next-generation solar cells in the wake of the ground- breaking study by O’Regan and Gr¨atzel [5]. Despite substantial research and development, DSSCs still need to increase their conversion effi- ciency in order to be implemented in real-world applications. It is an organic-inorganic composite layered system comprising a photoanode adsorbed with dye (electron transporting layer) [6–8], an electrolyte [9], a counter electrode (hole transporting layer) [10,11] and an FTO substrate. Among these, the photoanode layer significantly impacts the performance of the device by contributing to a number of DSSC working processes, including dye adsorption, photoelectron injection, light scattering, and electron transport/recombination [1,3]. The materials used in these layers greatly influence the conversion efficiency of the solar cell. The traditional material used in DSSC as a photoanode is TiO 2 [12,13]. In addition, several binary oxides have also been used as the electron transporting layer, such as ZnO [12,13], Nb 2 O 5 [14,15], In 2 O 3 [16] and SnO 2 [4] due to their well-matched electronic band structure * Corresponding author. ** Corresponding author. E-mail addresses: animelfarojim@gmail.com (M. Ani Melfa Roji), dr.ramchem93@gmail.com (P. Ram Kumar), ajithboscoraj@gmail.com (T. Ajith Bosco Raj). 1 Independent Researcher. Contents lists available at ScienceDirect Optical Materials journal homepage: www.elsevier.com/locate/optmat https://doi.org/10.1016/j.optmat.2023.113696 Received 6 January 2023; Received in revised form 21 February 2023; Accepted 14 March 2023