The effects of solvent treated PEDOT:PSS buffer layer in organic solar cells (original) (raw)
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The Effects of Solvent Treated PEDOT:PSS Layer to Enhance Polymer Solar Cells Efficiency
The present work is a detailed study of the poly(3,4-ethylenedioxyt hiophene):poly(styrenesulfonate) PEDOT:PSS films, were made to undergo different treatments to examine how they affected morphology, conductivity, transmittance, as well as the relative effect of the way the organic photovoltaic devices performed. This was done by using the PCPDTBT:PC 71 BM:SWCNTs and PCPDTBT:PC 61 BM mixtures. The process involves using DMSO and EG solvents for doping PEDOT:PSS and separately exposing the films to the vapour of ammonium hydroxide (NH4OH) solvent. After doping solvent was added to the PEDOT:PSS solution, , the conductivity and transmittance of PEDOT:PSS experienced a substantial increment, after which solvent treatment was performed by subjecting these films to NH4OH solvent. When devices were doped using PCPDTBT:PC 71 BM:SWCNTs or PCPDTBT:PC 61 BM with power conversion efficiency, The optimal organic photovoltaic devices achieved a 3.68% as compared to 2.20% for pristine PV devices or 2.67% instead of 1.51% for pristine devices, respectively. The solvent treatment played a significant part in enhancing conductivity in PEDOT:PSS films.
Applications of PEDOT:PSS in Solar Cells
Materials Research Forum LLC eBooks, 2021
Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is increasingly being used in the field of printed and flexible electronics in the form of electrode as well as intermediate layer. PEDOT:PSS belongs to the family of intrinsically conducting polymer materials whose members can conduct electricity in spite of their organic nature without the presence of metals. It is non-toxic, stable in the presence of air and humidity. Above all, it can be easily processed through conventional means. This chapter deals with the applications of PEDOT:PSS in organic solar cells (OSCs), dye sensitized solar cells (DSSCs) and silicon based hybrid solar cells. PEDOT:PSS is being used as electrode, buffer layer and hole conductive layer. It could manipulate the catalytic nature of counter electrode used in DSSCs. Whereas it may help to manipulate the morphological character in Si based hybrid solar cells along with enhancement of cell performance.
Semiconductor Science and Technology, 2014
The present work is a detailed study of the optical, morphological and electrical properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, films doped with ethylene glycol (EG) and multi-walled carbon nanotubes (MWCNT). The conductivity of PEDOT:PSS films doped with EG and MWCNT is higher than pristine PEDOT:PSS film. The optical transparency of PEDOT:PSS film decreases insignificantly after addition of MWCNT and EG. The films were further studied using atomic force microscopy, x-ray diffraction, Raman spectroscopy and Kelvin probe work function measurement, after which films of PEDOT:PSS with EG and MWCNT were optimized for the fabrication of solar cells. The optimized film was used as a hole extracting layer in a typical ITO/PEDOT:PSS/ P3HT:PCBM/Al solar cell. The suitable concentration for an optimized film was found to be 4% MWCNT and 1:4 ratio of EG to PEDOT:PSS. The performance of the device with doped PEDOT:PSS was found to improve in terms of short circuit current density (J SC ) and efficiency (η). The solar cell with a doped PEDOT:PSS layer showed higher J SC and η due to the increase in the interchains among PEDOT chains along with the introduction of MWCNT channels in PEDOT:PSS matrix. The degradation behavior of the cells was studied and it was found that both pristine and doped PEDOT:PSS cells showed similar trends of degradation. The performance degradation with time was also studied under variable environmental conditions, which showed different aging rates for the two devices.
Organic Electronics, 2015
efficiency in organic solar cells. To recover a hole transport functionality from aged PEDOT:PSS, three different solvents such as isopropyl alcohol (C 3 H 7 OH), ethanol (C 2 H 5 OH) and methanol (CH 3 OH) are investigated. Among them, it is found that isopropyl alcohol (IPA) yielded very uniform PEDOT:PSS thin film layer. This is because hydrophobic functional groups of IPA solvent facilitated the preferential solvation of phase separated hydrophobic PEDOT-rich agglomerates. However, when non-optimal concentration of IPA solvents was added into the aged PEDOT:PSS dispersion, the size of PEDOT-rich agglomerates was adversely enlarged. When organic solar cells were fabricated using more than a two-year-old PEDOT:PSS that was treated with IPA solvent, the resulting device performance of organic solar cells was fully recovered and became comparable or better than that of organic solar cells fabricated with fresh PEDOT:PSS.
The effect of solvent treatment on the buried PEDOT:PSS layer
Organic Electronics, 2017
Solvent treatment has been widely used to improve the device performance of both Organic Light Emitting Diodes (OLEDs) and Polymer Solar Cells (PSCs). One of the proposed mechanisms is the modification of the buried PEDOT:PSS layer underneath the organic active layer by the permeating solvent. By measuring the lateral electric conductivity of the PEDOT:PSS layer, the 3 orders of magnitude's enhancement on the conductivity after solvent treatment confirms that the solvent permeates through the top organic active layer and modifies the PEDOT:PSS layer. Using a "peel-off" method, the buried PEDOT:PSS layer is fully exposed and studied by UV-vis spectra, XPS spectra, and c-AFM images. The data suggest that the permeating solvent dissolves PSS, changes PEDOT:PSS' core-shell structure into a linear/coiled structure, and moves PSS from the bulk to the surface. As a result, PEDOT becomes more continuous in the bulk. The continuous conducting PEDOT-rich domains create percolating pathways for the current which significantly improve electric conductivity.
We systematically investigated the effect of the molecular weight of additives on the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by using different concentrations and molecular weights of polyethylene glycol (PEG) and ethylene glycol (EG). The conductivity enhancement depends on both the molecular weight and concentration of PEG used. The conductivity of PEDOT:PSS was enhanced from 0.3 S cm À1 to 805 S cm À1 with 2% PEG but to only 640 S cm À1 with 6% EG. PEGs with molecular weight higher than 400 have too low mobility to impart the required screening effect, and hence, the conductivity enhancement is less. Through FTIR, XPS and AFM investigations, the mechanism for the conductivity enhancement is found to be charge screening between PEDOT and PSS followed by phase separation and reorientation of PEDOT chains leading to bigger and better connected particles. The molecular weight and concentration of PEG also affect solar cell performances even though the conductivities are the same. Due to their high conductivity and high transmittance, ITO-free organic solar cell devices fabricated using PEDOT:PSS treated with 2% PEG anodes exhibited performance almost equal to that of the ITO counterparts. † Electronic supplementary information (ESI) available: PEDOT:PSS lm aer PEG400 and methanol treatment, XPS spectra of PEDOT:PSS with PEG400 and J-V curves and device performance tables of OSCs with PEDOT:PSS anodes treated with different concentrations of PEG. See
International Journal of Nanoparticles, 2014
This study aimed at studying the effect of the quality and thickness of PEDOT:PSS buffer layer that used in organic solar cells, on the performance of the cell. The effect of diluting the PEDOT:PSS dispersion with methanol on the morphology and thickness of the thin layer was studied using SEM and AFM. The results showed the dilution with 1:2. The effect of the buffer layer thickness on the performance of the solar cells based on P3HT:PCBM was studied using AFM and I-V measurements. It was found that a layer of thickness 40 nm is optimum for the best performance.
The effects of metal chlorides such as LiCl, NaCl, CdCl2 and CuCl2 on optical transmittance, electrical conductivity as well as morphology of PEDOT:PSS films have been investigated. Transmittance spectra of spun PEDOT:PSS layers were improved by more than 6% to a maximum of 94% in LiCl doped PEDOT:PSS film. The surface of the PEDOT:PSS films has exhibited higher roughness associated with an increase in the electrical conductivity after doping with metal salts. The improvement in the physical properties of PEDOT:PSS as the hole transport layer proved to be key factors towards enhancing the P3HT:PCBM bulk heterojunction (BHJ) solar cells. These improvements include significantly improved power conversion effeciency with values as high as 6.82% associated with high fill factor (61%) and larger short circuit current density (~18 mA.cm-2).
A Versatile Technique for the Fabrication of PEDOT: PSS Films for Organic Solar Cells
2012
Organic solar cells hold the potential of low-cost production as compared to inorganic solar cells, as well as the increase in efficiency. To realize these possibilities, the key is to fabricate most of the functional films in requisite structures via ambient solution-processed techniques. The PEDOT: PSS films, which are commonly used as an anode layer in organic electronic devices, were deposited on large-area ITO glass substrates under optimized conditions. The spin, spray, brush and brush+spray-coating techniques were utilized to examine their suitability in the fabrication of organic solar cells (OSCs). The films were characterized for their morphology, molecular structure, optical and electrical properties and results are compared with the existing data. A smooth and thin films of PEDOT: PSS were obtained by "Spray+Brush" coating method with attractive sheet-conductivity having potential in fabricating OSCs with different architectures.
Organic Electronics, 2018
Poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with Eu 3+ is spray deposited for creating an Anode buffer layer (ABL). The doping of Eu 3+ in PEDOT:PSS causes the down-shifting of the UV light to visible spectrum enhancing the photon concentration in this region. The use of electric field during the spray deposition of undoped and Eu 3+ doped PEDOT:PSS film improved the surface morphology and the electrical conductivity, which help to improve the solar cell performance. The organic solar cell (ITO/ABL/PTB7:PC 71 BM/Al) fabricated using the electric field assisted spray deposited Eu 3+ doped PEDOT:PSS ABL is shown improvement in the power conversion efficiency in comparison to the device fabricated using undoped PEDOT:PSS without electric field. This enhancement in the efficiency of the device in terms of current density and Fill factor can be attributed to an increase in the photon concentration in visible region due to the downshifting and improvement in the surface morphology and conductivity due to applied electric field during deposition.