**1. Introduction**

The growing energy demand of the society has engaged scientific community over the last decade in a search to enhance the light harvesting applications by utilizing nanostructured materials [1, 2]. The situation is quite obvious that the enlargement of solar cell efficiency through nanostructured materials is very important in the future. After the year 1991, a major breakthrough has come in the area of photovoltaics as dye sensitized solar cells (DSSCs) which possess modest functioning along with their advantageous features such as flexibility in device handling, low toxicity and respectable performance in diverse light conditions [3–7]. So far, TiO2 is a well-known material as photoelectrode having tremendous performance in DSSC device application [6–10]. However, despite of the outstanding performance, TiO2 tends to suffer from high recombination center of electrons and holes coupled with wide band gap (i.e., 3.2 eV) [11]. Thus, lot of research is being carried out with the aim to enhance device performance by reducing the

### **Figure 1.**

*Ion-implanted TiO2 photoanode for dye-sensitized solar cells.*

charge carrier recombination and improving electrical/optical performance of TiO2 photoelectrode [4–13]. In this regard, elemental doping is the most advantageous approach to modify its properties. Much work has been reported on synthesis processes adopted for preparation of TiO2. The chemical synthesis methods involve the complexity of chemical reactions and reproducibility is often problematic [14]. Physical doping, e.g., high-energy beam modifications have an adept of posttreatment produced titania films for further precisions, were essentially ignored and less effort was conducted in this direction for doping in photoanodes of DSSC [15–20]. The author have gone through the literature carefully and after keenly analyzing the reported results, proposed the better applicability of the ion implantation system and extensively examined the ion implanted TiO2 as photoanode in DSSC application.

The present piece of work is mainly focused on the ion implantation technique for the modification of photo-physical properties of titanium dioxide (TiO2) thin films for application as efficient photoelectrode material in dye sensitized solar cell application (**Figure 1**). The work focuses the finding towards the power conversion efficiency enhancement in DSSCs through ion implanted TiO2 and also discusses in detail the reported results and extensively examines the effects of ion implementation on the performance of dye sensitized solar cell. This chapter imparts knowledge in the field of ion implantation and its application in dye-sensitized solar cells. The fabrication technique adopted here is compatible with currently utilized fabrication techniques for the same and is of great interest to the readers working in the area of ion implantation for optoelectronic device application.
