Energy-Down-Shift CsPbCl₃:Mn Quantum Dots for Boosting the Efficiency and Stability of Perovskite Solar Cells

Abstract

Parasitic absorption by window layer, electrode layer, and interface layer in the near ultraviolet (UV) region is no longer negligible for high-efficiency perovskite solar cells. On the other hand, UV-induced degradation is also a big component of cell instability. Herein, CsPbCl 3 :Mn-based quantum dots (QDs) are synthesized and applied onto the front side of the perovskite solar cells as the energy-down-shift (EDS) layer. It is found that with very high quantum yield (∼60%) and larger Stokes shift (>200 nm), the CsPbCl 3 :Mn QDs effectively convert the normally wasted energy in the UV region (300−400 nm) into usable visible light at ∼590 nm for enhanced power conversion efficiency (PCE). Meanwhile, conversion of the UV rays eliminated a significant loss mechanism that deteriorates perovskite stability. As a result, external quantum efficiency in the UV region is significantly increased, leading to an increased short-circuit current (3.77%) and PCE (3.34%). Furthermore, the stability of perovskite solar cells has also been improved from 85% to 97% of their initial efficiency after exposure in the UV region with 5 mW/cm 2 intensity by 100 h. In parallel, the organic and silicon solar cells coated by EDS QDs also both confirm the above conclusion with PCE enhancements of 3.21% and 2.98%, respectively. These results suggest that the CsPbCl 3 :Mn QDs play a significant role in improving the efficiency and stability of photovoltaic devices. To our knowledge, this is the first report about CsPbCl 3 :Mn QD-assisted perovskite solar cells.

Synergy of Hydrophobic Surface Capping and Lattice Contraction for Stable and High‐Efficiency Inorganic CsPbI2Br Perovskite Solar Cells

“…In just a few years, the most celebrated perovskite solar cells have achieved power conversion‐efficiency (PCE) as high as 23.2% . However, their poor stability has been a challenging problem, mainly due to the inherent instability of their organic components . Gratifyingly, by replacing the organic cation with Cs + , their compositional stability is greatly improved …”

Recent Progress of All‐Bromide Inorganic Perovskite Solar Cells

“…Different from OIH‐PSCs, inorganic PSCs demonstrate excellent moisture and thermal stability by substituting the organic cations (MA + /FA + ) with inorganic ones (Cs + ) . There are three basic types, based on different halides, i.e., CsPbI 3 , CsPbBr 3 , and CsPbCl 3 . Detailed discussions about perovskite formation can be found in several review papers focusing on this topic .…”

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