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Research Highlight Archive
Tilted bulk heterojunction organic photovoltaic cells grown by oblique angle deposition
Ning Li and Stephen R. Forrest
Obliquely deposited donor chloroaluminum phthalocyanine (ClAlPc) films on indium tin oxide have surface feature sizes of ~30 nm, resulting in ClAlPc/C60 donor-acceptor heterojunctions (HJs) with approximately twice the interface area of HJs grown at normal incidence. This results in nearly twice the external quantum efficiency in the ClAlPc absorption band compared with analogous, planar HJs.
Three-dimensional fabrication of optically active microstructures containing an electroluminescent polymer
C. R. Mendonca, D. S. Correa, F. Marlow, T. Voss, P. Tayalia, and E. Mazur
In this paper, we use two-photon absorption polymerization to fabricate optically active microstructures containing the conductive and luminescent polymer poly(2-methoxy-5-(2 -ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). The microstructures retain the emission characteristics of MEH-PPV and allow waveguiding of locally excited fluorescence when fabricated on top of low refractive index substrates.
Organic light-emitting diode with liquid emitting layer
Denghui Xu and Chihaya Adachi
We demonstrate an original organic light-emitting diode (OLED) having a neat liquid host of 9-(2-ethylhexyl)carbazole (EHCz) doped with a guest emitter of 5,6,11,12-tetraphenylnapthacene (rubrene). We demonstrate that the liquid organic semiconducting layer transports charge carriers, leading to electroluminescence from rubrene.
In situ intercalation strategies for device-quality hybrid inorganic-organic self-assembled quantum wells
K. Pradeesh, J. J. Baumberg, and G. Vijaya Prakash
Thin films of self-organized quantum wells of inorganic-organic hybrid perovskites are formed from a simple intercalation strategy to yield well-ordered uniform films over centimeter-size scales that compare favorably with traditional solution-chemistry-synthesized thin films. We demonstrate the potential of this method for electronic and photonic device applications.
Enhanced open-circuit voltage in polymer solar cells
Jie Luo, Hongbin Wu, Chao He, Aiyuan Li, Wei Yang and Yong Cao
The open-circuit voltage of polymer solar cells can be enhanced by 0.3 V by inserting a thin layer of alcohol/water-soluble polyelectrolyte between the active layer and metal electrode. The origin of the increase can be attributed to the superposition of the built-in field with the interfacial dipole of the interlayer, and the existence of the interlayer as a dielectric was confirmed by ac impedance spectroscopy.
Improved bulk heterojunction organic solar cells employing C70 fullerenes
Steffen Pfuetzner, Jan Meiss, Annette Petrich, Moritz Riede, and Karl Leo
We show that the fullerene C70 is suitable to replace C60 as electron transporter and acceptor in small-molecule organic solar cells. The higher absorption of C70 leads to external quantum efficiencies of over 50% in the spectral range 500–700 nm due to a higher photocurrent, while fill factor and open-circuit voltage in solar cells containing C70 remain comparable to those with C60.
