Light management in hole transport layer-free perovskite solar cell by SPP and LSPR

In recent years, light management based on localized surface plasmon resonance (LSPR) effects in perovskite solar cells (PSCs) has received significant attention. However, the use of surface plasmon polariton (SPP) excitations in PSCs has been less studied. Meanwhile, hole transport layer-free perovskite solar cells (HTL-free PSCs) have garnered interest due to their lower cost. In this study, we improve light absorption in HTL-free PSCs by simultaneously utilizing LSPR and SPP effects. Au nanotriangles are employed on the surface of the back electrode to excite SPPs. The thickness of the perovskite layer is varied from 100 nm to 400 nm. The optimal periodicity and dimensions of the triangular nanoparticles are determined for each perovskite layer thickness. In the optimal structures with perovskite layer thicknesses of 100 nm, 200 nm, 300 nm, and 400 nm, absorption enhancements of 25%, 12.4%, 13%, and 4.3% are achieved, respectively. The interaction of light with SPP and LSP modes leads to improved solar cell performance. Furthermore, the short circuit current density (JSC) in structures with layer thicknesses of 100 nm and 200 nm increased from 16.7 mA cm-2 to 20.71 mA cm-2 and from 19.8 mA cm-2 to 21.86 mA cm-2, respectively. Other photovoltaic characteristics of the solar cell were obtained through optical-electrical numerical analysis. For the improved solar cell with a perovskite thickness of 100 nm, the values of open circuit voltage, efficiency, and fill factor were 0.847 V, 0.81, and 14.24%, respectively, representing increases of 1.1%, 2.4%, and 28.7% compared to the bare device. Additionally, in the solar cell with a thickness of 200 nm, an efficiency of 17.03% was achieved, showing a 12.5% improvement compared to the bare structure. Our research results facilitate the design of high-performance, ultra-thin, semi-transparent solar cells.