Photoresponse performance of Au (nanocluster and nanoparticle) TiO 2 : Photosynthesis, characterization and mechanism studies Zaid H. Mahmoud a,* , H.N.K. AL-Salman b , Shaymaa Abed Hussein c , Safaa Mustafa Hameed d , Yassir Mohammed Nasr e , Shahad Abdulhadi Khuder f , Saad khudhur Mohammed g , Usama S. Altimari h , Gunel T. Imanova i ,j ,k , Hamidreza Sayadi l , Ehsan kianfar m,* a Department of Chemistry, College of Sciences, University of Diyala, Iraq b Pharamaceutical Chemistry Department, College of Pharmacy, University of Basrah, Iraq c Department of Anesthesia Techniques, Al-Manara College For Medical Sciences, Maysan, Iraq d Department of Optics, College of Health & Medical Technology, Sawa University, Almuthana, Iraq e Department of Anesthesia Techniques, Mazaya University College, Iraq f Department of Pharmacy, Al-Hadi University College, Baghdad 10011, Iraq g Collage of Pharmacy, National University of Science and Technology, Dhi Qar 64001, Iraq h Department of Medical Laboratories Technology, AL-Nisour University College, Baghdad, Iraq i Institute of Radiation Problems, Ministry of Science and Education Republic of Azerbaijan, 9 B.Vahabzade str., AZ1143 Baku, Azerbaijan j Khazar University, Department of Physics and Electronics, 41 Mahsati Str., AZ1096, Baku, Azerbaijan k Western Caspian University, Baku, AZ-1001, Azerbaijan l Department of Chemical Engineering, Faculty Shahrood Branch, Shahrood Branch, Shahrood, Iran m Young Researchers and Elite Club, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran A R T I C L E INFO Keywords: Photosynthesis Nanocluster Nanoparticles HR-TEM UPS ABSTRACT In this study, gold (Au), nanoclusters (NC) and heterogeneous titanium dioxide (TiO 2 ) were successfully syn- thesized by low-temperature photoelectron spectroscopy. The chemical structure of Au-TiO 2 was characterized by XRD, EDX, XPS and HR-TEM. Optical properties were evaluated using PL and UV–Vis, and electrical prop- erties were evaluated using CV, CP, UPS and EIS parameters. The results showed that Au nanocluster (NCs) were converted into Au nanoparticles (NPs) during high sunlight, and the transfer mechanism was examined. In addition, the produced nanoparticles can form a Schottky barrier with TiO 2 , which affects the band structure. Moreover, the simultaneous synthesis of nanoparticles and nanoclusters adds an extra dimension to the under- standing of the photoelectronic behavior of structured photoelectrodes. Moreover, this research shows that good control of the photography process can result in more photos. This improvement is related to several factors, including the plasmonic field and coupling line bending. 1. Introduction The one-of-a-kind electronic setup of nanoclusters cements their potential as successful photosensitizers [1–4]. Nanoclusters display particular optoelectronic properties that set them separated from routine photosensitizers due to their uncommon basic components [5–9]. In spite of the fact that they share likenesses with nanoparticles in their composition, nanoclusters vary in that they are overwhelmingly shaped by thiol-containing ligands, as contradicted to the ligands of nanoparticles, which fundamentally work as surface stabilizers [10–13]. The noteworthy effect of this specific contrast is obvious, because it is one of the most reasons for the molecule-like characteristics that are not display in nanoparticles [14–16]. Moreover, in spite of their molecule- like behavior, nanoclusters vary from atoms due to the nearness of metal molecules shaping the nanoclusters [17–21]. Thus, unmistakable properties of metal nanoparticles such as their capacity to charge and show catalytic movement are noticeably shown in nanoclusters [22–25]. Nanoclusters are considered to be an unused and promising category of photosensitizers, with their potential in light vitality change frameworks being highlighted in later inquire about [26–28]. In spite of the starting victory of nanoclusters in photoelectrochemical applications, our cur- rent understanding of their photoelectrochemical behavior remains * Corresponding authors. E-mail addresses: zaidhameed_91@yahoo.com (Z.H. Mahmoud), ehsan_kianfar2010@yahoo.com, ehsankianfar775@gmail.com (E. kianfar). Contents lists available at ScienceDirect Results in Chemistry journal homepage: www.sciencedirect.com/journal/results-in-chemistry https://doi.org/10.1016/j.rechem.2024.101731 Received 15 March 2024; Accepted 15 August 2024 Results in Chemistry 10 (2024) 101731 Available online 19 August 2024 2211-7156/© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/).