Optical and EPR spectroscopy in pure and blended films of a novel low band gap polymer

Organic solar cells (OSCs) are lightweight, have adaptable colors, and can be produced in low‐cost procedures on transparent and flexible surfaces. This makes them attractive for markets in which other technologies cannot compete, for example in architectural and consumer product integration. However, both efficiencies and long term operational stability of OSCs do not yet meet the standards set by their inorganic counterparts. This review compiles the growing knowledge about how nanostructured carbon materials, such as fullerenes and carbon nanotubes, decisively influence the operational stability of organic photovoltaics. Firstly, important degradation pathways are introduced and a differential detection scheme is set up to find the dominant loss channel by means of state‐of‐the‐art characterization methods. Then, fullerenes ability to both stabilize and destabilize the donor polymer against photooxidation via different mechanisms (e.g., inner filter effect or radical scavenging) is examined in detail. The “burn‐in” problem, an initial rapid efficiency loss in PC60BM‐based OSCs, is shown to derive from light‐induced PC60BM dimerization, an effect that can also be positively exploited to reduce thermal degradation. Finally, thermal stabilization via additional approaches involving the fullerene derivative, such as crosslinking or incorporation into block copolymers, is presented.

show abstract

Stability of Organic Solar Cells: The Influence of Nanostructured Carbon Materials

Domínguez

Distler

Lüer

2016

Advanced Energy Materials

View full text Add to dashboard Cite

show abstract

Designing Small Molecule Organic Solar Cells with High Open‐Circuit Voltage

et al. 2017

View full text Add to dashboard Cite

Three extended 2,5‐dithienylthiazolo[5,4‐d]thiazole‐based small molecule chromophores are prepared via a sustainable direct arylation approach and their physicochemical and opto‐electrical material characteristics are analyzed toward integration in solution‐processed bulk heterojunction organic photovoltaics. Efficient charge separation and high values of the charge transfer state energy are derived from sensitive ground and excited state absorption and photoluminescence measurements on blends of the thiazolo[5,4‐d]thiazole‐based electron donor components with the PC71BM fullerene acceptor. Upon implementation in organic solar cells, a maximum power conversion efficiency of 2.7% and particularly high open‐circuit voltages (0.93−0.98 V) are observed, which are correlated to the charge transfer state energies as derived from photoluminescence, Fourier transform photocurrent spectroscopy and combined electrochemical and photophysical data. Furthermore, several loss processes at the origin of the modest short‐circuit current densities and fill factors are elucidated.

show abstract

Charge transfer in the weak driving force limit in blends of MDMO-PPV and dithienylthiazolo[5,4-d]thiazoles towards organic photovoltaics with high VOC

Nevil

Ling

Mierloo

et al. 2012

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Photoluminescence quenching together with polaron detection by electron paramagnetic resonance and photoinduced absorption (PIA) demonstrate an increasing charge transfer efficiency when the DTTzTz substituents are varied from thien-2-yl to 4-trifluoromethylphenyl and 4-cyanophenyl groups, correlating well with the increasing acceptor strength in this series of molecules. In line with this observation, there is a decrease in the effective optical bandgap relative to pure MDMO-PPV that becomes more pronounced along this series of acceptor compounds, reaching 0.12 eV in the blend with 4-CN-Ph-DTTzTz. Intermolecular interactions between the blend components lead to lower energy transitions which are found to contribute significantly to the device external quantum efficiency. The high V OC reached in devices based on MDMO-PPV:4-CN-Ph-DTTzTz blends meets the expectations for such a donor:acceptor combination. However, thermal activation of charge carrier recombination occurs because of the weak driving force for charge transfer, as shown by time-dependent PIA measurements, and this is suggested as a cause for the observed low photovoltaic performance.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Optical and EPR spectroscopy in pure and blended films of a novel low band gap polymer

Cited by 3 publications

References 10 publications

Stability of Organic Solar Cells: The Influence of Nanostructured Carbon Materials

Stability of Organic Solar Cells: The Influence of Nanostructured Carbon Materials

Designing Small Molecule Organic Solar Cells with High Open‐Circuit Voltage

Charge transfer in the weak driving force limit in blends of MDMO-PPV and dithienylthiazolo[5,4-d]thiazoles towards organic photovoltaics with high VOC

Contact Info

Product

Resources

About