Ce-Pr-Nd]:CsPbI1.8Br1.2: Stability enhanced light harvester in perovskite solar cells, energy storage material for batteries, and an OER/HER electro-catalyst

Abstract

Current work for the first time investigates the impact of the lanthanide co-doping strategy on the fully inorganic cesium lead halide (CsPbI1.8Br1.2) perovskite by using oxides of cerium, praseodymium, and neodymium forming [Ce-Pr-Nd]:CsPbI1.8Br1.2. The doped perovskite material expressed an enhancement in the opto-electronic, crystalline, and morphological aspects upon lanthanide addition besides gaining an impressive stability at the ambient conditions. The dark brown doped thin films heated at 200 °C succeeded in acquiring a bandgap energy of between 1.66 and 1.73 eV showing stable response for 28 days revealed by ultra-violet spectrophotometry. Furthermore, the desired black phase cubic crystalline geometry was exposed by x-ray diffraction with an average crystallite size of 62.61 nm. In terms of morphology, the doping treatment not only enhanced the performance of CsPbI1.8Br1.2 but also it acted as a passivator for curing the surficial defects. The performance of the pristine and doped perovskite material was assessed by utilizing it as the light trapping material inside perovskite solar cells where highly improved performance was obtained for the doped absorber layer with 15.53 % efficiency, 68 % fill factor, 15.01 mA cm−2 short circuit current, and an excellent open circuit voltage of 1.14 V. Furthermore, the perovskite undoped and doped materials were fabricated in the form of an electrode for assessment of charge storage potential for battery application. With the electro-active behavior signifying surficial faradic redox process, there was an augmentation in the battery capacity with doping which boosted from 228 to 311.3 mAh g−1. With the series resistance as lows as 0.62 Ω, faster reaction kinetics were revealed for doped electrode. The oxygen and hydrogen evolution potential of the developed pristine and doped materials as bifunctional catalysts was assessed by estimation of the overpotential values and Tafel slope values. The Tafel slope values of the doped electro-catalysts were lower in comparison to the pristine material suggestive of the synergism between perovskite and dopants giving rise to an excellent energy generation capacity. The Tafel slope for oxygen and hydrogen generation of the doped electrode were 256.4 and 120.6 mV dec−1 indicating excellent hydrogen evolution. The stability and endurance of the developed material reflected from their original characteristics retention makes them excellent materials for use in energy application, specifically, [Ce-Pr-Nd]:CsPbI1.8Br1.2 excelled over pristine material showing the profound impact of doping on host lattice.