The effects of the PEDOT:PSS acidity on the performance and stability of P3HT:PCBM-based OSCs


The optical transmittance, electrical conductivity and morphology of PEDOT:PSS treated with ammonium hydroxide (NH4OH) have been investigated. Transmittance spectra of spun PEDOT:PSS layers were enhanced slightly as a result NH4OH treatment while surface of the films has exhibited variation in the roughness and an increase in the electrical conductivity. Improvement in the physical properties of PEDOT:PSS is shown to be the key factor in enhancing the power conversion effeciency (PCE) with values as high as 4% associated with high fill factor (FF) of 57%, open circuit voltage (VOC) of 0.64 V and larger short circuit current density (JSC) of 11 mA cm−2. Stabiltiy test of the devices has been carried out over a period of 2 months, when a device incorporating PEDOT:PSS with pH ~ 4 as the hole transport layer has shown an improved stability with a degredation in PCE in about 43% whereas JSC has decreased in about 20% compared to a device incorporating pristine PEDOT:PSS with PCE decreased in about 66% and JSC in about 50% over the stated period of test. These effects have been ascribed to the increased acidity of the hole transport layer.

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Kadem, B.Y., Al-Hashimi, M., Hasan, A.S. et al. The effects of the PEDOT:PSS acidity on the performance and stability of P3HT:PCBM-based OSCs. J Mater Sci: Mater Electron 29, 19287–19295 (2018).

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