Solid-state solar cell

In a later publication,96 the standard free energy of formation of the products, AG in V, was used instead of AH in Eq. (23) so that comparisons could be made with the commonly reported efficiencies of solid state solar cells. For the reduction of carbon dioxide to organic compounds, the optical conversion efficiency of the system is the sum of the efficiencies for each product. Thus, it can be given as... 

The low efficiencies could be due to lack of intimate contact (interface) between the sensitizer, which is hydrophilic, and spirobifluorene, which is hydro-phobic. Moreover, surface charge also plays a significant role in the regeneration of the dye by the electrolyte [97]. In an effort to reduce the charge of the sensitizer and improve the interfacial properties between the sensitizer and spirobifluorene, amphiphilic heteroleptic ruthenium (II) sensitizers (48-53) have been used. These sensitizers show excellent stability and interfacial properties with hole-tfansport materials, which improved the yields of the solid-state solar cell significantly. 

A solid-state solar cell was assembled with an ionic liquid—l-ethyl-3-methylimidazolium bis(trifluoromethanesulfone)amide (EMITFSA) containing 0.2 M lithium bis(trifluoromethanesulfone)amide and 0.2 M 4-tert-butylpyridine—as the electrolyte and Au or Pt sputtered film as the cathode.51,52 The in situ PEP of polypyrrole and PEDOT allows efficient hole transport between the ruthenium dye and the hole conducting polymer, which was facilitated by the improved electronic interaction of the HOMO of the ruthenium dye and the conduction band of the hole transport material. The best photovoltaic result ( 7p=0.62 %, 7SC=104 pA/cm2, FOC=0.716 V, and FF=0.78) was obtained from the ruthenium dye 5 with polypyrrole as the hole transport layer and the carbon-based counterelectrode under 10 mW/cm2 illumination. The use of carbon-based materials has improved the electric connectivity between the hole transport layer and the electrode.51... 

Preliminary results were recently reported [145] on the use of CdTe electrodeposition on diamond in the fabrication of a solid-state solar cell based on the boron-doped p-type diamond/n-type CdTe junction. In this cell, the wide-bandgap diamond is an optical window that generates photovoltage, whereas the narrow-bandgap CdTe generates photocurrent. We note that no appropriate p-type material for the fabrication of optical windows has existed so far therefore, one would use an n-type CdS window coupled with narrow-bandgap p-type CdTe. However, the pro-... 

Fan Q, McQuillin B, Bradley DDC, Whitelegg S, Seddon AB (2001) A solid-state solar cell using sol-gel processed material and a polymer. Chem Phys Lett 347 325... 

The main obstacle to creating liquid junction solar cells is photocorrosion of semiconductor electrodes, which reduces considerably their lifetime. In order to prevent, for example, anodic photocorrosion, a well-reversible redox couple is introduced into an electrolyte solution, so that the reaction of oxidation of the red component competes for photoholes with the reaction of photodecomposition of the electrode material (see Section IV.2). With the aid of this method, photocorrosion has been practically prevented in certain types of photocells and the duration of their continuous operation has been increased up to about one year. Yet, there are other, more subtle mechanisms of electrode degra-dation, which has hitherto prevented the lifetime of photoelectrochemical cells from becoming comparable with the 20-year lifetime of solid-state solar cells. 

In its action, the regenerative type PEC cell is a full analog of the solid-state solar cell based on the semiconductor/metal junction called Schottky diode (see, e.g., [4]). Band diagram of the Schottky diode both in the dark and in the tight is presented in Fig. 4, a and b respectively. In the dark, Fermi levels of the semiconductor and the metal are equal (cf Fig. 2, a), F = F gt Upon illumination of the semiconductor, a photopotential emerges in it, (ppj,. 

Fig. 4. Energy diagram of a solid-state solar cell of the Schottky diode type a - in the dark, b - in the light (upon closing external circuit with the load).

With some types of cells corrosion was practically abolished, and service life up to one year was achieved for outdoor operation in the mid-Europe climat [20], Yet certain degradation processes other than corrosion (e g, ion exchange in the outmost layer of the semiconductor electrode [9]) restrict the service life of PEC cells which still are inferior to the solid-state solar cells whose service life comes to 10-20 years. 

Is it now possible to evaluate the prospects of the liquid-junction solar cells To do so, one must have in mind that they are approaching commercial solid-state solar cells in efficiency though are much inferior as to their service live. Their potentials seem not to be exhausted yet, however, since their life story is much shorter than that of solid-state cells. 

Analytic models of photoelectrochemical devices closely resemble models of solid-state solar cells (see, e.g., Refs. 133-145). Several analytic current-voltage relationships have been derived which use the general approach described above and differ in their treatment of surface reactions and recombination within the depletion and neutral layers. The model of Gartner,146 developed for a p-n junction device, is commonly used in the analysis of photoelectrochemical devices.147 149 Recombination and thermal generation... 

The in situ interface conditioning of p-lnP by photoelectrochemical processes, described in Section 2.4.2, is a key procedure for the preparation of efficient and stable photovoltaic and photoelectrocatalytic solar cells and surface analyses wiU be presented that describe the induced chemical and electronic changes. The ternary chalcopyrites CulnSe2 and CulnS2 have meanwhile been developed for use in commercially available solid-state solar cells. For the sulfide-based cell, the use of a toxic KCN etch step of Cu-rich CulnS2 to remove Cu-S surface phases is considered as deleterious for wide-scale application and an electrochemical method will be presented in Section 2.4.3 that replaces the chemical etching procedure. 

Takahashi, K., et al. 2004. Performance enhancement by blending an electron acceptor in Ti02/polyphenylenevinylene/Au solid-state solar cells. Chem Lett 33 1042. 

When choosing a solar simulator for PEC research, one should carefully consider the orientation of the light exit port. Most solar simulators have their exit port oriented vertically, i.e., shining down. This is convenient for solid-state solar cells, but a bit of a hassle for PEC cells containing a liquid electrolyte -one would have to use a mirror since the photoelectrode is mounted vertically in most PEC cells. Fortunately, several manufacturers offer the possibility to have the light exit sideways. Some solar simulator manufacturers even offer integrated electromechanical shutters, with minimum exposure times as short as 200 ms and lifetimes >10 cycles. There are many manufacturers of solar simulators, and some well-known names include Oriel Instruments (Newport), Asahi, Abet Technologies, Luzchem, Wacom, Spire, Voss, etc. 

Lee H, Leventis HC, Moon 8-J, Chen P, Ito 8, Haque SA, Torres T, Niiesch F, Geiger T, Zakeeruddin 8M et al (2009) Pb8 and Cd8 quantum dot-sensitized solid-state solar cells old concepts, new results . Adv Funct Mater 19 2735-2742... 

Lee J, Leventis HC, Haque SA, Torres T, Gratzel M, Nazeeruddin MdK (2011) Panchromatic response composed of hybrid visible-light absorbing polymers and near-IR absorbing dyes for nanocrystalline Ti02-based solid-state solar cells. J Power Source 196 596-599... 

A few research conducted to fabricate the Electrospun PVDF-HFP membrane by electrospinning process from asolutionofpoly(vinylidenefluoride-cohexafluoropropylene) in a mixture of acetone/N, N-dimethylacetamide to encapsulate electrolyte solution [45, 46], Although the solar eneigy-to electricity conversion efficiency of the quasi-solid-state solar cells with the electrospun PVDF-HFP membrane was slightly lower than the value obtained from the conventional liquid electrolyte solar cells, this cell exhibited better long-term durability because of the prevention of electrolyte solution leakage. 

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