In recent years, researchers have studied different solar cell designs to promote widespread deployment. Recently researchers are strategically boosting organic solar cell efficiency due to its advantages over traditional ones. Organic solar cells that use perovskite materials have lower fabrication costs, greater flexibility and tunability.
Researchers from Soochow University’s Suzhou Key Laboratory of Novel Semiconductor-Optoelectronic Materials and Devices developed a method to reduce phase segregation in wide-band gap perovskites. Although these tandem cells might theoretically attain high PCEs and stabilities, they confront hurdles due to phase segregation which degrades wide-bandgap perovskite performance and hinders interconnection layer recombination.
Thereby improving the performance and stability of perovskite/organic tandem cells. Their strategy described involves incorporating a pseudo-triple-halide alloy into mixed halide perovskites containing iodine and bromine.
Despite having a maximum certified power conversion efficiency (PCE) of 19.4%, organic solar cells still fall behind silicon solar cells. To improve efficiency and stability, researchers propose merging organic cells with mixed halide wide-bandgap perovskites to generate perovskite/organic tandem solar cells.
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Experimental Results
The researchers have used perovskite/organic tandem solar cells to evaluate their proposed technique for suppressing phase segregation in wide-bandgap perovskites. Initial testing showed that tandem solar cells had a PCE of 25.82%, with a certified PCE of 25.06% and an operating stability of 1,000 hours.
Challenges and Solutions in Tandem Solar Cells
The researchers discovered that introducing their pseudo-halogen thiocyanate ions into iodine/bromide mixed halide perovskites prevents halide elements from separating within the solar cell. Thiocyanate eventually slowed crystallization preventing ions from moving and so facilitating the transfer of electric charge in the solar cells.
Future Prospects of Efficient Organic Solar Cells
In the future, this methodology could be extended and applied to other wide-bandgap perovskites of various compositions. This could eventually lead to the development of potential new perovskite/organic photovoltaics. These future versions could be more stable under various light intensities have higher PCEs and function for longer periods before deterioration.
Source: Suppression of phase segregation in wide-bandgap perovskites
