Blends solar cells

Lee J, Vandewal K, Yost SR, Bahlke ME, Goris L, Baldo MA, Manca JV, Van Voorhis T (2010) Charge transfer state versus hot exciton dissociation in polymer-fullerene blended solar cells. J Am Chem Soc 132 11878... 

S.C. Jain, T. Aernouts, A.K. Kapoor, V. Kumar, W. Geens, J. Poortmans, R. Mertens, I-V Characteristics of dark and illuminated PPV-PCBM blends solar cells, Synth. Met. 148 (2005) 245-250. 

Figure 7.10 Tandem solar cell structure for polymer blend solar cells, based on the design demonstrated by Hadipour et al. (2006). In this all-solution-processed device, the top cell consists of a polymer PCBM bulk heterojunction with an absorption maximum of 550 nm and preferentially absorbs short-wavelength light, while the bottom cell is made from a bulk heterojunction of PCBM with a red-absortring polymer and absorbs longer-wavelength light. The composite gold-PEDOT PSS internal layer connects the two cells in...

Goris L., Poruba A., Hod akova L., Vanecek M., Haenen K., Nesladek M., Wagner P., Vanderzande D., de Scheppe, L. and Manca J. V. (2006), Observation of the subgap optical absorption in polymer-fullerene blend solar cells , Appl. Phys. Lett. 88, 052113. 

Polymer-fuUerene solar cells represent the most widely studied concept of polymer-molecule blend solar cells to date. Examples for the appHcation of other acceptor dye molecules can be found here [218-220]. 

Pacios and Bradley observed bimolecular recombination for PFB F8BT blend solar cells spin cast from chloroform, thus explaining in part the comparatively low EQEs generally observed for these devices [242]. 

Moore, J.R., Albert-Sefiried, S., Rao, A., Massip, S., Watts, B., Morgan. D.J., Friend, R.H., McNeill, C.R., and Sirringhaus, H. (2011) Polymer blend solar cells based on a high-mobility najAiflialenediimide-based polymer acceptor device physics. 

Yin, C Kietzke, T., Neher, D., and Hdrhold, H.H. (2007) Photovoltaic properties and exciplex emission of polyphenylenevinylene-hased blend solar cells. Appl. Phys. Lett., 90, 092116. 

A new approach to model-based simulation of disordered-polymer-blend solar cells. Adv. Fund. Mater., to appear. Thiedmann, R., Fleischer, F., Hartnig,... 

Mori D, Benten H, Okada I, Ohkita H, Ito S. Low-bandgap donor/acceptor polymer blend solar cells with efficiency exceeding 4%. Adv Energy Mater 2014 4(3) 1301006. 

Kimber, R. G. E. Waiker, A. B. Schroder-Turk, G. E. and Cleaver, D. X, Bicontinuous minimal surface nanostructures for polymer blend solar cells, Phys. Chem. Chem. Phys., 12,844-851 (2010) DOI 10.1039/b916340a. 

Attaching perylene moieties as side groups allows achievement of high concentration without affecting the electronic structure of the polymer backbone. Putting 16% perylene moieties as side chains predictably results in more efficient energy transfer, observed with polymer 360, both in solution and solid state (emission band at 599 nm). Although no PLED device with 360 has been reported, this material showed excellent performance in solar cells (external photovoltaic QE = 7%, in blend with PPV) [434]. 

Fig. 34 Illustration of the BHJ solar cell, (a) The four layers from bottom to top are Ag, blend of P3HT and PCBM, graphene and quartz, (b) Energy level diagram of the cell. (Reprinted with permission from [258])...

Fig. 15 Charge-transfer state electroluminescence (EL) for several polymer fullerene blends used in donor/acceptor organic solar cells. Adapted with permission from [184]. Copyright 2009 American Chemical Society...

Fig. 16 Parameters for defining the charge-transfer state energy cx in organic solar cells. Charge-transfer state energy for MDMO-PPV PCBM blend device determined by Fourier transform photocurrent spectroscopy and electroluminescence measurements. Reprinted figure with permission from [188]. Copyright 2010 by the American Physical Society...

One of the most promising uses of C60 involves its potential application, when mixed with 7r-conjligated polymers, in polymer solar cells. Most often the so-called bulk heterojunction configuration is used, in which the active layer consists of a blend of electron-donating materials, for example, p-type conjugated polymers, and an electron-accepting material (n-type), such as (6,6)-phenyl-Cgi -butyric acid methyl ester (PCBM, Scheme 9.6).38... 

It is the purpose of this chapter to introduce photoinduced charge transfer phenomena in bulk heterojunction composites, i.e., blends of conjugated polymers and fullerenes. Phenomena found in other organic solar cells such as pristine fullerene cells [11,12], dye sensitised liquid electrolyte [13] or solid state polymer electrolyte cells [14], pure dye cells [15,16] or small molecule cells [17], mostly based on heterojunctions between phthalocyanines and perylenes [18] or other bilayer systems will not be discussed here, but in the corresponding chapters of this book. 

Short-Circuit Current. Key parameters for efficient charge collection by plastic solar cells are the hole and electron mobilities of the interpenetrating networks and the lifetime of the carriers within this network. While the lifetime of the carriers in the bulk heterojunction blends has already been discussed as a peculiarity of the interpenetrating network, the mobility of the individual components is a true material parameter. The interplay between network quality and mobility and their impact on the short-circuit current will be discussed by means of a simple model in this section. 

The use of low bandgap polymers (ER < 1.8 eV) to extend the spectral sensitivity of bulk heterojunction solar cells is a real solution to this problem. These polymers can either substitute one of the two components in the bulk hetero junction (if their transport properties match) or they can be mixed into the blend. Such a three-component layer, comprising semiconductors with different bandgaps in a single layer, can be visualized as a variation of a tandem cell in which only the current and not the voltage can be added up. 

In this section we discuss a method of controlled material degradation for individual organic semiconductors and also for the blends used in bulk heterojunction solar cells [37]. The degradation is studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and by determining current/voltage characteristics (I/V measurements) of the devices. 

In order to get a fast characterization of the degradation processes, the individual semiconductors (MDMO PPV and Ceo) and a blend of the two semiconductors as used in bulk heterojunction solar cells are studied under illumination in pure oxygen. ATR-FTIR spectra before and after an 8 h degradation process and difference spectra showing only the spectral changes... 

---