Design Rules for Efficient Organic Solar Cells

Zhu, Zhengguo; Mühlbacher, David; Morana, Mauro; Koppe, Markus; Scharber, Marcus; Waller, David; Dennler, Gilles; Brabec, Christoph J.

doi:10.1007/978-3-540-79359-5_13

Cited by 7 publications

(2 citation statements)

References 57 publications

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“…Finally, the two aforementioned methods, which involve control of sterics, are commonly implemented and balanced together with the fused ring method in order to optimize backbone planarity. Although many other routes for controlling molecular planarity exist (via secondary bonding interactions such as hydrogen bonding), these three are the primary ones used in PSCs to improve charge carrier and exciton transport [40][41][42].…”

Section: Inter-and Intramolecular Conformation Controlmentioning

confidence: 99%

Recent design strategies for polymer solar cell materials

Bilby

Kim

2010

Pure and Applied Chemistry

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Recent design tools for tuning the properties of conjugated polymers for efficient polymer solar cells (PSCs) are briefly reviewed. Based on limitations in the solar-to-electric energy conversion process imposed by material properties, recent research has focused on lowering the highest occupied molecular orbital (HOMO) level, reducing the bandgap, and controlling the molecular conformation and donor-acceptor phase separation. Additionally, the stability of PSCs can be improved through molecular design. Finally, a few less-conventional material design strategies for device improvement through polymer-polymer blends and triplet utilization are introduced. Molecular design has been an invaluable tool in controlling these material properties.

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Section: Inter-and Intramolecular Conformation Controlmentioning

confidence: 99%

Recent design strategies for polymer solar cell materials

Bilby

Kim

2010

Pure and Applied Chemistry

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“…With the increasing demand for large bitrates of the high-speed data communication industry 3,4 , VCSELs are dominating short reachOptical Interconnects, OIs, and present the preferred choice for replacing other semiconductor lasers also at medium distances due to their inherent advantages. VCSEL structure can be easily and rapidly tested on-wafer at low cost, show low power consumption, low threshold current, high-speed modulation 5 , low-temperature sensitivity 6 , and small symmetric beam divergence of the fundamental mode, favoring good optical coupling 7 . Further, VCSELs have achieved >70% power conversion efficiency 8 by using stacked active layers connected by tunnel junctions.…”

Section: Introductionmentioning

confidence: 99%

Multi-hole aperture VCSELs: single mode, high power, low resistance

Maricar,

Sapunov,

Tian

et al. 2024

Vertical-Cavity Surface-Emitting Lasers XXVIII

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The essential performance parameters of present generations of Vertical Cavity Surface Emitting Lasers (VCSELs) like output power, f3dB cut-off frequency, are limited by extrinsic parameters. The most important among them is the shift of the gain maximum out of resonance with the DBR transmission due to increased heating of the active layer with increasing current, leading to a red shift of the emission. Another important limitation of f3dB is the unavoidable resistance by the p-type mirror and capacitance of the actual device generations. We present here a novel Multi-Hole Aperture (MuHA) VCSEL approach 1 , based on variable aperture shapes and sizes, leading to increased output power for single/multi-mode emission, reduced series resistance, and larger f3dB of the devices. Holes in symmetric or asymmetric arrangements are etched from the top to the oxidizable layer(s). The aperture shape and size is realized by controlled oxidation of the oxidizable layer(s) through the holes. The holes are subsequently filled with gold, which effectively remove heat from the active layer. In MuHA VCSELs, the temperature of the active area for any given current is thus at least 50% lower than that of a comparable VCSELs processed using a "classical" design, resulting in larger rollover current, f3dB,… Combining MuHA to Multi-Aperture devices called Multi Aperture VCSELs (MAVs) is expected to lead to pseudo single mode emission with an output power of 8-10 mW across 50 μm Multi-Mode Fiber (MMF), enabling to cover much larger transmission distances than hitherto.

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Donor–Acceptor Shape Matching Drives Performance in Photovoltaics

Schiros

Kladnik

Prezzi

et al. 2013

Advanced Energy Materials

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While the demonstrated power conversion efficiency of organic photovoltaics (OPVs) now exceeds 10%, new design rules are required to tailor interfaces at the molecular level for optimal exciton dissociation and charge transport in higher efficiency devices. We show that molecular shape-complementarity between donors and acceptors can drive performance in OPV devices. Using core hole clock (CHC) X-ray spectroscopy and density functional theory (DFT), we compare the electronic coupling, assembly, and charge transfer rates at the interface between C-60 acceptors and flat- or contorted-hexabenzocorone (HBC) donors. The HBC donors have similar optoelectronic properties but differ in molecular contortion and shape matching to the fullerene acceptors. We show that shape-complementarity drives self-assembly of an intermixed morphology with a donor/acceptor (D/A) ball-and-socket interface, which enables faster electron transfer from HBC to C-60. The supramolecular assembly and faster electron transfer rates in the shape complementary heterojunction lead to a larger active volume and enhanced exciton dissociation rate. This work provides fundamental mechanistic insights on the improved efficiency of organic photovoltaic devices that incorporate these concave/convex D/A materials

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Design Rules for Efficient Organic Solar Cells

Cited by 7 publications

References 57 publications

Recent design strategies for polymer solar cell materials

Recent design strategies for polymer solar cell materials

Multi-hole aperture VCSELs: single mode, high power, low resistance

Donor–Acceptor Shape Matching Drives Performance in Photovoltaics

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