Mr. Ingo Riedel Profile

Ingo Riedel

at Carl von Ossietzky Univ Oldenburg

SPIE Involvement:

Author

Publications (1)

Proceedings Article | 3 November 2004 Paper

Toward highly efficient photogeneration and loss-free charge transport in polymer-fullerene bulk heterojunction solar cells

Ingo Riedel, Jurgen Parisi, Vladimir Dyakonov, Pavel Schilinsky, Christoph Waldauf, Christoph Brabec

Proceedings Volume 5520, (2004) https://doi.org/10.1117/12.557630

KEYWORDS: Solar cells, Polymers, External quantum efficiency, Absorption, Temperature metrology, Composites, Internal quantum efficiency, Heterojunctions, Photovoltaics, Semiconductors

Read Abstract +

Different material combinations of two conjugated polymers, each blended with the methanofullerene acceptor phenyl-C₆₁ butyric acid methyl ester (PCBM) have been evaluated focusing on their potential for application as absorber material in polymer-fullerene bulk-heterojunction solar cells. Devices based on these solution processable composite materials have been studied by means of temperature dependent profiling of the photocurrent. In combination with measurements of the incident photon conversion efficiency, this technique probes the charge carrier recombination losses within the absorber material. Samples based on material composites with a low mobility-lifetime (μτ) product of the charge carriers (OC₁C₁₀-PPV: PCBM) exhibit a thermally activated photocurrent throughout the temperature range from 100 K to 350 K. The latter issue is attributed to the presence of shallow traps inside the bulk of the absorber limiting the photocurrent by recombination and scattering of the charge carriers with defects. Accordingly, the active layer thickness must be kept low at the expense of optical absorption. In contrast, the photocurrent in devices based on absorber materials with a high μτ product, P3HT: PCBM, saturates at a certain temperature and becomes constant, reflecting that all photogenerated charge carriers are efficiently extracted within their lifetime prior to recombination. Thus, solar cells with absorber materials demonstrating a high μτ product, have the potential to be designed with relatively thick absorber films above 100 nm. A large active layer thickness is a prerequisite for industrial deposition techniques, e.g., screen-printing, and improves the mechanical stability of large area flexible solar cells. As consequence of a high μt product the increase of the active layer thickness to L=350 nm in P3HT: PCBM photovoltaic devices results in a higher density of photogenerated charge carriers due to improved light absorption. Consequently, a strongly increased short-circuit current density of up to 15.2 mA/cm² was obtained for devices with absorber thickness of 350 nm which rising the power conversion efficiency up to 3.1 %.

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years