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ISU and Ames Laboratory researchers have developed a method of producing organolead halide perovskites for the use of low cost, high power conversion efficiency(PCE) photovoltaic cells.  Since perovskite solar cells are tunable, the theoretical PCE limit is higher than that of silicon solar cells, and organolead halide perovskites have enhanced moisture stability and improved carrier relaxation times compared to single halide perovskite photovoltaics.

The market for commercial solar cells has been dominated by single junction cells with silicon as the sole absorber layer for decades. Although these cells have become price competitive with other energy sources, modern silicon based solar cells have nearly reached the theoretical PCE limit and therefore the cost per watt produced and the watts per kg has reached a plateau. Perovskite type crystal structures as an absorber layer offers the potential for greatly increasing the efficiency of the single junction silicon cells, particularly if used in a multi-junction cells. Perovskite cells are tunable in nature, able to top the best PCE of silicon cells and amenable to use with silicon cells. The most common material investigated for these perovskites are organolead compounds, however, typical processing of organolead mixed halide perovskites require dissolution of the individual single halide species, which often results in aggregation. This aggregation reduces the homogeneity of the crystalline structure, creating defects that can lower efficiency.  Iowa State University and Ames Laboratory researchers have developed a method of producing perovskites by processing in the solid phase.  In this method, the halides diffuse in the solid phase which creates a more homogeneous system with higher purity, allowing for improved photovoltaic properties.

• Improved moisture stability

• High power conversion efficiency

• Improved carrier relaxation time

• Improved crystalline homogeneity

Solar cells