Neutron reflectometry and hard X-ray photoelectron spectroscopy study of the vertical segregation of PCBM in organic solar cells

Urbina, Antonio; Abad, José Antonio; Romero, Antonio J. Fernández; Lacasa, Jesús S.; Colchero, J.; Gonzalez-Martinez, Juan Francisco; Rubio-Zuazo, J.; Castro, Germán R.; Gutfreund, Philipp

doi:10.1016/j.solmat.2018.10.004

Cited by 7 publications

(2 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, the FOM is defined as the evaluation factor of the fitting, which is calculated by the average of the absolute difference between the logarithms of the data and simulation as where Y Q is the measured intensity and S Q is the simulated intensity for each Q -point, and N and p represent the number of experimental data points and the free parameters in the fit, respectively . Different from the NR fitting for the 0% DIO sample in our previous work, PBDB-T and ITIC are supposed to be distributed in a gradient concentration in the film depth direction; hence, a model with continuously varying SLD was used. The best fit for the corresponding data yields an FOM of 0.10.…”

Section: Resultsmentioning

confidence: 99%

Quantitative Determination of the Vertical Segregation and Molecular Ordering of PBDB-T/ITIC Blend Films with Solvent Additives

Wang

Liu

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

The vertical component distribution of bulk heterojunction (BHJ) active film shows a significant impact on determining the device performance in polymer solar cells (PSCs). Processing solvent additives are well known for regulating the BHJ active layer morphology; however, there are few reports regarding the quantitative evaluation of the effect. Herein, a study of the quantitative determination of the vertical segregation in combination of molecular ordering of PBDB-T/ITIC blend films with various 1,8-diiodooctane (DIO) contents is provided. A 0.5% (volume ratio) DIO-added blend film achieves the highest power conversion efficiency of 10.75%. The reduced performance of the PSCs resulted from the excessive vertical component segregation and overcrystallization investigated by various techniques. X-ray photoelectron spectroscopy indicates that DIO aggravates the PBDB-T enrichment region at the air side. Neutron reflectivity further quantitatively figures out the phase separation effect. Although increased crystallinity of ITIC and a higher face-on ratio of PBDB-T in active layer were obtained with increased DIO content approved by grazing-incidence wide-angle X-ray scattering (GIWAXS), the enhanced vertical distribution along with the enhanced crystal size of ITIC leads to the reduced performance of the PSCs due to the reduced carrier transportation paths between donor and acceptor.

show abstract

Section: Resultsmentioning

confidence: 99%

Quantitative Determination of the Vertical Segregation and Molecular Ordering of PBDB-T/ITIC Blend Films with Solvent Additives

Wang

Liu

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…Organic solar cells (OPV) show tremendous potential due to their inexpensive and easy solution processing. − Though raw materials are presently very expensive for commercialization, once economies of scale are reached this hurdle will dissipate. However, the low power conversion efficiency of OPV remains a big challenge. ,, To address these issues, new materials are being developed, including low band gap semiconducting polymers and small molecules. − At the same time, efforts to understand the morphology of OPV in terms of processing and molecular structures is critical to designing molecules that improve their performance. − Our work focuses on investigating the morphology of a semiconducting poly(3-hexylthiophene) (P3HT) polymer under shear-flow.…”

Section: Introductionmentioning

confidence: 99%

Brush-Painted Solar Cells from Pre-Crystallized Components in a Nonhalogenated Solvent System Prepared by a Simple Stirring Technique

et al. 2020

View full text Add to dashboard Cite

Extensive efforts have been employed to improve the power conversion efficiency of organic solar cells. One of the most successful approaches is the morphological control of the solar cells' active layer, the bulk heterojunction of the donor and acceptor. However, many morphological control techniques have faced challenges transferring from the lab to industrial scale due to lack of process scalability, stringent environmental requirements, and high temperature requirements during thermal annealing. In this report, we develop a novel strategy to manipulate the organic solar cells' morphology using a simple stirring technique. By stirring of poly(3-hexylthiophene) (P3HT) and mixtures of P3HT and phenyl-C61-butyric acid methyl ester (PCBM) solutions in a nonhalogenated and less toxic solvent system, more perfect P3HT crystals can be made. Networks of P3HT crystal fibrils, percolated P3HT crystal domains, and PCBM phase separated domains are critical factors for optimal solar cell performance. We demonstrate a simple fabricating technique utilizing brush painting to easily deposit the precrystallized components of the devices' active layer. As a result, the painted solar cells (without thermal annealing) achieve similar performance to a control group prepared via the commonly used standard process of spin-coating from a mixture of P3HT and PCBM dissolved in dichlorobenzene, followed by thermal annealing at an elevated temperature. Moreover, this report reveals an increase in power conversion efficiency of 60% to 90% from the painted devices made from precrystallized components (after stir solutions) in comparisons to the devices made from the pristine components (before stir solutions). We have demonstrated an easy thin-film processing technique that achieves high degrees of morphological control, showing promise not only for applications in other semiconducting polymers, but also demonstrating a technique that is scalable for mass production.

show abstract

Production of PV Modules

Urbina

2022

Green Energy and Technology

View full text Add to dashboard Cite

Neutron reflectometry and hard X-ray photoelectron spectroscopy study of the vertical segregation of PCBM in organic solar cells

Cited by 7 publications

References 38 publications

Quantitative Determination of the Vertical Segregation and Molecular Ordering of PBDB-T/ITIC Blend Films with Solvent Additives

Quantitative Determination of the Vertical Segregation and Molecular Ordering of PBDB-T/ITIC Blend Films with Solvent Additives

Brush-Painted Solar Cells from Pre-Crystallized Components in a Nonhalogenated Solvent System Prepared by a Simple Stirring Technique

Production of PV Modules

Contact Info

Product

Resources

About