Adsorption and electron injection studies in N719 sensitized Ag−, Au− implanted and O2 annealed titania films

• Published in: Optical materials 2024-08, Vol.154, p.115633, Article 115633
• Main Authors: Vemula, Sai Krishna, Chelli, Sai Manohar, Biswas, Chinmoy, Soma, Venugopal Rao, Raavi, Sai Santosh Kumar
• Format: Article
• Language: English
• Subjects: Adsorption; Interfacial electron injection; Ion-implantation; N719/TiO2 interface; O2 annealing; Sequential; Transient absorption
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2024.115633

The device performance of novel solar cell configurations with porphyrin, hybrid perovskite-based materials as sensitizers depends on the interfacial processes and engineered interfaces with characteristic material properties can be fabricated employing energetic ion implantations. In this experimental work, the dye adsorption, optical absorption and interfacial electron injection in N719 sensitized Ag−, Au−, sequentially impinged and O2 annealed titania films were studied. Prior to the dye sensitization process, impinged samples were fabricated employing mono-ion type, sequential implantations and a set of the as-implanted films were annealed at 450 °C for 1 h in O2 environment. The N719 molecules are adsorbed onto Ag−, Au− impinged films through SCN ligands, indicated by the appearance of new Raman modes ν(Ag-S), ν(Au-S) respectively. The 1MLCT, 3MLCT bands of the dye molecules are altered upon implantation and annealing processes. A fast interfacial electron injection process with τ2∼3.7 ps has been observed in the sensitized annealed sequentially impinged film at 6 × 1015 ions cm−2 (sensitized pristine TiO2 exhibits τ2∼51 ps) and is attributed to Ag−, Au− implants introducing new states to the conduction band of anatase TiO2. The ability of ion-implantation technique to introduce new states to the band structure of materials has enormous significance in photo-catalytic, water-splitting, solar cell and hot electron injection technologies. [Display omitted] •Ball and stick representations of Ag− and Au− implanted TiO2 matrix.•New Raman modes ν(Ag-S), ν(Au-S) respectively observed in N719 sensitized Ag−, Au− as-implanted, annealed films.•Tuning 1MLCT, 3MLCT bands of N719 molecules in sensitized as-implanted, annealed films.•Fast electron injection τ2∼3.7 ps observed in sensitized annealed sequentially impinged film at 6 × 1015 ions cm−2.•Modified morphology of TiO2 upon implantation and annealing processes.