[Gd3+-Ho3+-Dy3+]:CsPbI2.4Br0.6: Synergism between thermal optimization and lanthanide doping for enriched photoelectrical and electrochemical contraptions

This investigation, for the first time, reports the designing and application of the novel [Gd3+-Ho3+-Dy3+]:CsPbI2.4Br0.6 (GHD:CPVSK) heterostructure developed via tri-lanthanide doping route. For the prolonged duration of 28 days, GHD:CPVSK retained its optical output with the band gap energy spanning around 1.64–1.69 eV. The spin coated thin films were characterized with cubic phase and smoother morphology. As light harvester layer inside perovskite solar cell, GHD:CPVSK reached an efficiency of 16.73 % and an expanded open circuit voltage (Voc) of 1.1 V. GHD:CPVSK is a bifunctional electro-catalyst which has moderate oxygen generation activity while the pure hydrogen production activity was remarkable with the HER overpotential (ηHER) and Tafel slope value of 136 mV and 118.1 mV dec−1, respectively. In terms of the charge storage activity, the designed nickel foam electrode decorated with the GHD:CPVSK attained multi-step redox activity with the unit capacity of 555.24 mAH g−1 showing the excellency of this material in storing of charge. Furthermore, this electrode has remarkably minimal equivalent series resistance (Rs) i.e. 0.67 Ω which indicates the favorability of the facilitated diffusion of the charges on the interface between GHD:CsPbI2.4Br0.6 perovskite semiconductor electrode and NaCl electrolyte.