Band edge movement in dye sensitized Sm-doped TiO₂ solar cells: a study by variable temperature spectroelectrochemistry

Abstract

Pure TiO 2 and 8 at.% Sm-doped TiO 2 nanoparticles are prepared via a novel hydrolysis followed by a hydrothermal process at 473 K for 24 h and successfully used into the photoanode of dye sensitized solar cells (DSSCs). The performance of DSSC based on 8 at.% Sm-doped TiO 2 is significantly better compare to DSSC based on undoped TiO 2 . The J sc is 14.53 mA cm -2 and η is 6.78%, which is 15% and 5% higher than that of DSSC based on undoped TiO 2 , respectively. The results of variable temperature spectroelectrochemistry study shows that the conduction band edge of 8 at.% Sm-doped TiO 2 shift positively. The lower conduction band position enhances the driving force of electrons and improves the electron injection efficiency from the lowest unoccupied molecular orbital (LUMO) of the dye to the conduction band (CB) of TiO 2 , and the narrower band gap expands the response in the visible region and increases the utilization percentage of sunlight. These are all contributed to enhanced the performance of cells based on 8 at.% Sm-doped TiO 2 photoanode. The as prepared Sm-doped TiO 2 material is proven in detail to be a better photoanode material than pure TiO 2 .

Physico-Chemical Properties and In Vitro Antifungal Evaluation of Samarium Doped Hydroxyapatite Coatings

“…The peak corresponding to the binding energy of 1082.93 eV can be assigned to Sm 3d5/2 [50]. In agreement with previous studies [51], the binding energy of Sm 3d5/2 as revealed in Figure 8i suggested that the chemical state of Sm is +3. The XPS results provided obvious information for the successful doping of HAp with samarium.…”

Performance improvement of dye-sensitized solar cell by introducing Sm3+/Y3+ co-doped TiO2 film as an efficient blocking layer

“…The possible down-conversion luminescence mechanism points out that Sm 3+ ions in the 6 H 5/2 ground state are excited to the 6 P 3/2 excited state by absorbing photons with wavelength 395 nm, followed by radiationless deactivation into the 4 G 5/2 , which are the initial levels of the emission 4 G 5/2 → 6 H 5/2 or 4 G 5/2 → 6 H 7/2 . These results are in good agreement with the previous studies [9][10][33][34], which only involved single dopant.…”

“…It is well known that rare-earth (RE) compounds can efficiently convert incident light from either near-infrared or ultraviolet spectral range to visible range owing to their specific 4f electron structure and unique properties. To increase light absorption range of a solar cell, RE compounds are doped in DSSCs acting as either up-conversion [4][5][6][7][8] or down-conversion luminescent medium [3,[9][10][11][12][13][14][15] to extend the spectral-response range of photo-absorber. Numerous studies have demonstrated that introducing dual dopants from RE group (i.e.…”

Photodiode‐like behavior of jelly dye‐sensitized donor‐acceptor dendrimers

“…The energy band‐gap was calculated from the on‐set of absorption, at lower energies, using the equation …”