The contact between the polymer active layer and the electrode is one the most critical interfaces in polymer solar cells. In this article, we report the progress of interface engineering in polymer solar cell research, where the multiple functions of the interfacial materials will be discussed. The vertical composition profile in polymer:fullerene blends is an emerging topic, and the interlayer effect on the vertical phase separation and device performance will be highlighted. We also discuss the energy level alignment at the bulk heterojunction (BHJ) interface, with the aim of providing a better understanding towards the route of high efficiency polymer solar cells.

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Interface investigation and engineering – achieving high performance polymer photovoltaic devices

A structured polymer solar cell architecture featuring a large interface between donor and acceptor with connecting paths to the respective electrodes is explored. To this end, poly-(3-hexylthiophene) (P3HT) nanorods oriented perpendicularly to indium tin oxide (ITO) glass are fabricated using an anodic aluminum oxide template. It is found that the P3HT chains in bulk films or nanorods are oriented differently; perpendicular or parallel to the ITO substrate, respectively. Such chain alignment of the P3HT nanorods enhanced the electrical conductivity up to tenfold compared with planar P3HT films. Furthermore, the donor/acceptor contact area could be maximised using P3HT nanorods as donor and C60 as acceptor. In a photovoltaic device employing this structure, remarkable photoluminescence quenching (88%) and a seven-fold efficiency increase (relative to a device with a planar bilayer) are achieved.

Poly(3-hexylthiophene) Nanorods with Aligned Chain Orientation for Organic Photovoltaics

The invention provides an organic light-emitting device which sequentially comprises an anode conductive substrate, a functional layer, a light-emitting layer, a cathode layer and an encapsulation layer Enclosed space is formed by the anode conductive substrate and the encapsulation layer, and the functional layer, the light-emitting layer and the cathode layer are arranged in the enclosed space The encapsulation layer sequentially comprises a protective layer, a barrier layer and a polyethylene terephthalate film, wherein the barrier layer sequentially comprises a first organic barrier layer, an oxide layer, a second organic barrier layer and a nitride layer, the first organic barrier layer and the second organic barrier layer are made of different materials, the first organic barrier layer, the oxide layer, the second organic barrier layer and the nitride layer form a basic structure, and the barrier layer is formed by multiple basic structures in a repeated mode The invention further provides a preparation method of the organic light-emitting device The method can effectively reduce erosion of moisture and oxygen on the organic light-emitting device, and the service life of the organic light-emitting device can be remarkably prolonged

Organic light-emitting device and preparation method thereof

The enhancement of surface sensitivity by grazing incidence geometry facilitates the investigation of nanostructures in thin films and at surfaces. The technique provides information about the surface roughness, lateral correlations, sizes and shapes of objects (such as, nanoparticles and nanostructures) positioned on top of the surface or in a region near the surface. Grazing incidence small-angle neutron scattering (GISANS) overcomes the limitations of conventional small-angle neutron scattering for extremely small sample volumes in the thin-film geometry. Although real space analysis techniques, such as atomic force microscopy, provide easy access to surface structures, reciprocal space analysis techniques, such as GISANS, provide several advantages: (i) average statistical information over the large illuminated sample surface can be detected and (ii) buried lateral structures can be probed without damage, using the variable-probed depth as a function of the incident angle. To illustrate the potential applications and challenges of GISANS, several different examples of thin nanostructured polymer films are reviewed. Nanostructures in triblock copolymer thin films are studied in the bulk as well as at the polymer-air and the silicon–polymer interface. Confined nanostructures in a dewetted diblock copolymer film are also discussed in terms of contrast and experimental settings. Grazing incidence small-angle neutron scattering (GISANS) allows for the investigation of nanostructures in thin films and at surfaces due to the use of a reflection geometry. Possibilities and challenges of GISANS are reviewed with several different examples of thin nanostructured polymer films. With GISANS buried lateral structures can be probed destruction free using the variable-probed depth as function of the incidence angle. By this, averaged statistical information is detected over the large illuminated sample surface.

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Grazing incidence small-angle neutron scattering: challenges and possibilities

Improvement in the hole collection of polymer solar cells by utilizing gold nanoparticle buffer layer

Significant progress is being made in the photovoltaic energy conversion using organic semiconducting materials. One of the focuses of attention is the morphology of the donor−acceptor heterojunction at the nanometer scale, to ensure efficient charge generation and loss-free charge transport at the same time. Here, we present a method for the controlled, sequential design of a bilayer polymer cell architecture that consists of a large interface area with connecting paths to the respective electrodes for both materials. We used the surface-directed demixing of a donor conjugated/guest polymer blend during spin coating to produce a nanostructured interface, which was, after removal of the guest with a selective solvent, covered with an acceptor layer. With use of a donor poly(p-phenylenevinylene) derivative and the acceptor C60 fullerene, this resulted in much-improved device performance, with external power efficiencies more than 3 times higher than those reported for that particular material combination s...

Nanostructured Organic Layers via Polymer Demixing for Interface-Enhanced Photovoltaic Cells

The disclosed invention consists of high efficiency organic solar cells (0) with a multi layer structure, consisting of cathode layer (1), organic acceptor layer (2), organic donor layer (3), conductive anode layer (4) and a substrate layer (5), where an adjustment of electronic levels of separated layers is achieved by introduction of at least one intermediate matching layer (x). In conjunction with the selection of active layer (3) consisting of cyanine dyes with appropriate counterions (e.g. hexafluorophosphate), high performance organic solar cells with long lifetimes can be fabricated with a fast and simple manufacturing method.

Multi layer organic thin film solar cell

L'invention porte sur un dispositif de conversion photoelectrique (1) qui comporte : au moins un element de conversion photoelectrique (10) comportant au moins une couche de conversion photoelectrique organique ou une couche inorganique comprenant des points quantiques ou des perovskites; au moins une premiere structure de reseau (20) agencee sur un premier cote de l'element de conversion photoelectrique; au moins une seconde structure de reseau (30) agencee sur un second cote de l'element de conversion photoelectrique; ladite ou lesdites premieres structures de reseau (20) etant agencees afin de diriger une partie de lumiere proche infrarouge de la lumiere incidente sur ladite premiere structure de reseau (20) dans ledit element de conversion photoelectrique (10), ladite ou lesdites secondes structures de reseau (30) etant agencees afin de reflechir au moins une partie de ladite partie de lumiere proche infrarouge de retour dans ledit element de conversion photoelectrique (1), et afin de faire passer une lumiere visible a l'exterieur du dispositif de conversion photoelectrique.

Dispositif photovoltaïque de captage de lumière

The performance and stability of cyanine dye—C60 heterojunction solar cells were investigated both in the regular and the inverted geometry. While active layers absorption was stable under inert environment (N2), we observed a dependence on cell performances as a function of storage time for the regular geometry. This was attributed to the influence of the coating solvent on the cyanine dye film/buffer layer interface as well as the top electrode/buffer layer interface. Chlorobenzene as solvent and silver as low work function electrode were proposed as good candidates to improve stability. The inverted geometry was found to be another solution for the stability enhancement due to well protected active layers and more stable interfaces.

Roland Hany

Papers

Nanostructured Organic Layers via Polymer Demixing for Interface-Enhanced Photovoltaic Cells

Multi layer organic thin film solar cell

Dispositif photovoltaïque de captage de lumière

Performance and Stability of Organic Trimethine Cyanine Dye—C60 Heterojunction Solar Cells