Pr-Doped Inorganic SrCeO₃ Perovskite Nanophosphors as Activated Compact Layers for (CH₃NH₃)₂CuBr₄ Perovskite Solar Cells

Abstract

In this study, we report a modified architecture for perovskite solar cells (PSCs) by introducing a compact layer to modify the trap states between the semiconductor oxide (TiO 2 ) and the active perovskite layer, the latter of which can affect carrier transport, recombination, and charge collection in the devices. In the present work, less toxic copper-based organic (CH 3 NH 3 ) 2 CuBr 4 and rareearth (Pr 3+ ) ion-doped inorganic SrCeO 3 perovskites (compact layer) were synthesized by a solution-based method. The structural analysis confirmed that the organic and inorganic samples have perovskite phases. The morphological studies showed crystalline nanosheet structures and needle-like morphologies of organic and inorganic perovskites, respectively. From diffuse reflectance spectroscopy measurements, the band gaps of (CH 3 NH 3 ) 2 CuBr 4 and SrCeO 3 :Pr 3+ were found to be 1.81 and 3.3−3 eV, respectively. The X-ray photoelectron spectroscopy analysis suggested the coexistence of Pr 3+ and Pr 4+ ions in the sample, and photoluminescence studies showed that the emission of the Pr 3+ -doped inorganic perovskite phosphor extended to the red-light region, which was suitable for the absorption range of the (CH 3 NH 3 ) 2 CuBr 4 perovskite active layer. Hybrid (CH 3 NH 3 ) 2 CuBr 4 PSCs were fabricated using compact praseodymium (Pr 3+ )-ion-doped inorganic SrCeO 3 layers. Dark I−V measurements of the samples revealed the effects of the Pr 3+ concentration on defect passivation properties. The devices with Sr 1−x CeO 3 :xPr 3+ had an estimated reduced trap state density and further afforded a power conversion efficiency (PCE) of 1.15% with an open-circuit voltage of 0.92 V, a short-circuit current density of 1.58 mA, and a fill factor of 78.9%.