Hybrid solar cells semiconductors

In bulk (or dispersed) heterojunctions, nanocrystals are blended into the polymer to create a heterogeneous composite with a high interface surface area. In this hybrid solar cell concept, photo induced charge separation is favored between high electron affinity inorganic semiconductors and relatively low ionization potential polymer. The maximum power conversion efficiency has reached 2.8 % under AM 1.5 illumination condition by using the composite of tetrapods of CdSe nanocrystals and MDMO-PPV [4], while the PCE of the device based on the composite of CdTe nanorods and MEH-PPV is only 0.052 % in similar conditions [5]. 

L. Zhao, Z. Lin, Crafting Semiconductor Organic-Inorganic Nanocomposites via Placing Conjugated Polymers in Intimate Contact with Nanocrystals for Hybrid Solar Cells. Adv. Mater. 2012,24,4353-4368. 

I. Gur, N. A. Fromer, C.-P. Chen, A. G. Kanaras, A. P. Alivisatos, Hybrid Solar Cells with Prescribed Nanoscale Morphologies Based on Hyperbranched Semiconductor Nanocrystals. Nano Letters 2007,7,409-414. 

X. Tingling and Q. Qiquan, Conjugated polymer-inorganic semiconductor hybrid solar cells. Energy Environmental Science, 2011.4. http //www.off-grid.fr/. 

Gur, et al. Hybrid solar cells with prescribed nanoscale morphologies based on hyperbranched semiconductor nanocrystals. Nano Letters, 2006. 7(2) p. 409-414. 

Hybrid solar cells where a conjugated polymer is blended with an inorganic nanoparticle have also been the subject of intense research in recent years. BHJ hybrid solar cells have been fabricated by blending inorganic materials such as ZnS, Ti02, and CdSe in the form of nanoparticles, nanorods, or nanowires with a semiconductor polymer into a thin It is... 

In any case, it is perceived from the above discussion that the problem of longterm chemical stability of polycrystalline semiconductor liquid junction solar cells is far from being solved. Still, as already pointed out in the early research, any practical photovoltaic and PEC device would have to be based on polycrystalline photoelectrodes. Novel approaches mostly involving specially designed PEC systems with alternative solid or gel electrolytes and, most importantly, hybrid/sensitized electrodes with properties dictated by nanophase structuring - to be discussed at the end of this chapter - promise new advances in the field. 

Lira-Cantu, M. Norrman, K. Andreasen, J. W. Casan-Pastor, N. Krebs, F. C. 2007. Semiconductor oxides as electron acceptors in hybrid organic-inorganic solar cells. ECS Trans. 3 1-9. 

There has been a growing interest in inorganic/organic hybrid materials in recent years with expectations for new or improved properties, which are not exhibited or attainable by using the parent materials separately. The usefulness of such materials has been best manifested by recent successful studies of dye-sensitized solar cells, which typically employ thin film electrodes of porous oxide semiconductors such as TiOz, and whose surface is modified with sensitizing... 

Silicon is a material of major technological importance since it forms the basis of a vast range of electronic devices such as transistors, microprocessors and solar cells. It is also likely to be used in numerous future technologies including atomic scale devices [17,18], ultra dense storage devices [19], quantum computers [20,21] and hybrid molecular devices [22]. The surfaces of silicon are the most thoroughly studied of all semiconductor surfaces and there are numerous known surface reconstructions [23]. In this section we... 

In this chapter, I give an account of the historical development of semiconductor photoelectrochemistry and nanostructured photovoltaic devices in Section 1.2, and then Sections 1.3-1.6 provide a brief introduction to the major cell types discussed in the remainder of the book the ETA (extremely thin absorber) cell, organic and hybrid cells, dye-sensitised solar cells (Gratzel cells) and regenerative solar cells. 

In a recent pubHcation, Alivisatos and co-workers reported the making of hybrid nanorods-polymer solar cells and their properties [122]. These solar cells were made by spin casting of a solution of both poly(3-hexylthiophene) (hole acceptor) and CdSe nanorods (electron acceptor) onto indium tin oxide glass substrates coated with poly(ethylene dioxythiophene) doped with polystyrene sulfonic acid and aluminum as a top contact. Nanorods have been used in composites so as to improve the carrier mobiHty. Indeed, the latter can be high for some inorganic semiconductors, but it is typically extremely low for conjugated polymers [123]. The use of the nanorods suppHes an interface for the charge transfer as well as a direct path for electrical transport. Also, because of their anisotropy, self-assembly of these nanorods is observed by electron microscopy. It shows... 

Conventional solar cells are built from inorganic silicon-like materials. Efficiency of such solar cells is high, but they originate from expensive materials and special techniques are required for their processing. Recently hybrid and photoelectrochemical solar cells [54] have been cost effective alternatives for conventional silicon solar cells. The correspondence between the photon absorption and charge separation events is the point of differentiation between the photovoltaic effect in a semiconductor junction, and that in a photon-induced generation of a chemical potential in natural systems, i.e. photosynthesis. In the latter, and this is very simple but highly relevant in the context of artificial photosynthetic systems, the point in space at which the... 

A hybrid nanosystem which consists of semiconductor nanoparticles and organic dye J-aggregate may be self-assembled in RMs (Fig. 5) [4], In this structure, the dye adsorbed to the nanoparticle surface operates as spectral sensitizer and nanocrystal size stabilizer simultaneously. The hybrid nanosystem of this kind may be a key element of solar cells. 

---