|Posted: Jan 19, 2018|
Tuning perovskite solar cells with nanoparticle additives(Nanowerk News) Researchers have employed carbon nanoparticles with an average diameter of 20 nm in high efficiency state-of-the-art perovskite solar cells to control the morphology of the perovskite film.
|Recently, perovskite solar cells have attracted considerable interest among the photovoltaics research community, because of their high solar-to-electric power conversion efficiencies and low fabrication costs.|
|In new work, reported in Advanced Energy Materials ("Carbon Nanoparticles in High-Performance Perovskite Solar Cells"), an international research team has for the first time, carbon nanoparticles (CNPs) containing functional groups have been incorporated in perovskite solar cells.|
|Carbon nanoparticles. a) Top SEM image, b) size distribution curve, c) UV–vis absorbance and photoluminescence spectra of CNPs in DMF:DMSO 4:1 for 375 and 400 nm excitation wavelengths, and d) IR spectra of CNPs. (© Wiley-VCH Verlag) (click on image to enlarge)|
|"we find that the functional groups of the CNPs interact with perovskite components already in the precursor solution resulting in a larger grain size, better thermal stability, and hydrophobicity of the perovskite film," write the scientists. "Whereas efficiencies above 18% could be maintained after adding the CNPs, the hysteresis in the current–voltage curves was considerably decreased compared to reference devices."|
|The films show larger grain sizes and increased thermal stability when CNPs were added to the perovskite by dispersing them in the precursor solution.|
|Whereas a power conversion efficiency larger than 18% could be maintained, the hysteresis was decreased to negligible values despite using a TiO2 contact.|
|Different perovskite solutions image and device schematic. a) CsM perovskite solution (left) and the CsM/0.08CNP solution (right), crosssectional SEM images of b) CsM and c) CsM/0.08CNP solar cells and d) schematic of full perovskite solar cell. (© Wiley-VCH Verlag)|
|Films containing CNPs were found to be more hydrophobic. NMR analyses showed that hydrogen bonds are formed between formamidinium cations and functional groups of CNPs already in solution.|
|"This study shows that additives are a promising path toward morphology tuning and increasing thermal stability," the authors conclude.|
|By Michael Berger – Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny.|
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