Efficient Semitransparent Perovskite Solar Cells Using a Transparent Silver Electrode and Four-Terminal Perovskite/Silicon Tandem Device Exploration

Abstract

Four-terminal tandem solar cells employing a perovskite top cell and crystalline silicon (Si) bottom cell offer a simpler pathway to surpass the efficiency limit of market-leading single-junction silicon solar cells. To obtain cost-effective top cells, it is crucial to develop transparent conductive electrodes with low parasitic absorption and manufacturing cost. The commonly used indium tin oxide (ITO) shows some drawbacks, like the increasing prices and high-energy magnetron sputtering process. Transparent metal electrodes are promising candidates owing to the simple evaporation process, facile process conditions, and high conductivity, and the cheaper silver (Ag) electrode with lower parasitic absorption than gold may be the better choice. In this work, efficient semitransparent perovskite solar cells (PSCs) were firstly developed by adopting the composite cathode of an ultrathin Ag electrode at its percolation threshold thickness (11 nm), a molybdenum oxide optical coupling layer, and a bathocuproine interfacial layer. The resulting power conversion efficiency (PCE) is 13.38% when the PSC is illuminated from the ITO side and the PCE is 8.34% from the Ag side, and no obvious current hysteresis can be observed. Furthermore, by stacking an industrial Si bottom cell (PCE = 14.2%) to build a four-terminal architecture, the overall PCEs of 17.03% (ITO side) and 11.60% (Ag side) can be obtained, which are 27% and 39% higher, respectively, than those of the perovskite top cell. Also, the PCE of the tandem cell has exceeded that of the reference Si solar cell by about 20%. This work provides an outlook to fabricate high-performance solar cells via the cost-effective pathway.

Hysteresis and Instability Predicted in Moisture Degradation of Perovskite Solar Cells

“…As predicted by the general percolation theory, when the occupation probability is below approximately 50% in 2D or 30% in 3D, , there is no way for water diffusion. However, the diffusion becomes possible once the initial nonzero W value exceeds 50% (Figure c,d), which reminds us of the well-documented percolation threshold in 2D. − Such discoveries could also be echoed by the experimental observations, where perovskite stability was enhanced in the presence of moisture when the ion diffusion channel was suppressed, despite the fragile nature of MAPbI 3 in the presence of water . Combining the results of Figure c, it is apparent that the W update or collapse of the perovskite, only accelerates the diffusion, whereas the initial random assignment makes the continuous diffusion possible.…”

Highly Efficient Semitransparent Perovskite Solar Cells for Four Terminal Perovskite-Silicon Tandems

“…Thus, a balance between overall transparency and efficiency is a critical consideration. Recent results clearly indicate that for 4T tandem perovskite-silicon cells, top cells make a major contribution toward higher efficiencies (Table S1 ,,,,− ).…”

Bifacial, Color-Tunable Semitransparent Perovskite Solar Cells for Building-Integrated Photovoltaics

“…A major challenge in realizing high-performance ST-PSCs is the replacement of the opaque metal electrode with a transparent one, which allows light transmission without compromising the charge collection efficiency. Recently, different strategies have been implemented to develop a good semitransparent rear electrode, including the use of thin metal layers (Au, Ag, Cu/Au bilayer), silver nanowires, graphene, conductive polymers (PEDOT/PSS), and dielectric/metal/dielectric multilayer stuctures . The best performances so far have been achieved by using transparent conductive oxides (TCOs), such as indium tin oxide (ITO), indium-doped zinc oxide, , and aluminum-doped zinc oxide .…”