(Sm/Eu/Tm)3+ doped tantalum semiconductor system for photovoltaic and electrochemical functionality amplification

This work reports the synthesis, characterization, and energy focused applications of the novel lanthanides co-doped tantalum pentoxide hetero-system (Sm³⁺-Eu³⁺-Tm³⁺:Ta₂O₅). Ln³⁺-doped Ta₂O₅ express excellent opto-electronic features reflected by the narrow band gap energy of 3.87 eV. Different vibrations confirm the presence of Ta–O–Ta and Ta–O bonds. The synthesized system possesses orthorhombic geometry with 59.46 nm particle size. With the smoother and compact morphology, the synthesized material succeeds in augmenting the performance of different systems aimed at energy applications. Fully ambient perovskite solar cell device fabricated with the Ln³⁺-doped Ta₂O₅ as an electron transport layer excels in achieving an efficiency and fill factor of 14.17% and 76% under artificial sun. This device was marked by the negligible hysteresis behavior showing profound photovoltaic performance. The electrochemical activity of the Ln³⁺-doped Ta₂O₅ decorated electrode was evaluated for electrical charge storage potential with pseudocapacitive behavior. With the highest specific capacitance of 355.39 F/g and quicker ionic diffusion rate, the designed electrode excels conventionally used materials. Electro-catalysis of water with Ln³⁺-doped Ta₂O₅ material indicates its capacity for H₂ production with the lowest overpotential and Tafel slope values of 148 and 121.2 mV/dec, while the O₂ generation is comparatively lower. With the stable electrochemical output, this rare earth modified material has the potential to replace conventionally used environmentally perilous and costly materials.