Polymer solar cells fill factor

He, I. Zhong, C. Huang, X. Wong, W.-Y. Wu, H. Chen, L. Su, S. Cao, Y., Simultaneous enhancement of open-circuit voltage, short-circuit current density, and fill factor in polymer solar cells. Adv. Mater. 2011, 23, 4636-4643. 

Katz et al. investigated the performance of the polymer solar cells under elevated temperatures in the range of 25-60 °C, which represents real operating conditions due to heating under solar irradiation [122]. While the open circuit voltage ( oc) decreased linearly with temperature, the short circuit current (Jsc) and the fill factor (FF) increased up to about 50 °C, followed by a saturation region (Fig. 28). These effects overcompensated the dropping 7oc and thus the efficiency was maximal for a 50 °C cell temperature [122]. 

Synthesis via the sulfinyl route led to a reduced number of defects on the MDMO-PPV donor polymer and showed some improved performances in MDMO-PPV PCBM bulk heterojunctions [ 167,168]. The lower defect density resulted in a more regioregular (head-to-taU) order within the MDMO-PPV, leading to charge carrier mobihty improvements and ultimately to an improved efficiency of 2.65% for MDMO-PPV PCBM based bulk heterojimc-tions [ 169]. This was accompanied by a fill factor of 71% [169], which to date has not been exceeded by any other polymer solar cell device. 

With the prospect of long-term stability [185,188] and the abiUty to print polymer solar cells [188] with power conversion efficiencies of 4-5%, EQEs of over 75%, internal quantum efficiencies approaching unity [194], and fill factors of almost 70% [18,21], the P3HT PCBM system is at the moment highly optimized. The main limitations in reaching larger power conversion effiden-... 

Fig. 44 Light intensity dependence of short circuit photocurrent (filled circles) and open circuit voltage of laminated POPT (MEH-)CN-PPV diffuse bilayer polymer solar cells. The scaling factor of the current calculates as 1.02. (Reprinted with permission from [32], 1998, Macmillan Publishers Ltd)...

Origin of the reduced fill factor and photocurrent in MDMO-PPV PCNEPV all-polymer solar cells. Adv. Funct. Mater, 172167-2173. 

T. Stubhan, N. Li, N. A. Lueehinger, S. C. Halim, G. J. Matt and C. J. Bra-bec. High Fill Factor Polymer Solar Cells Ineorporating a Low Temperature Solution Processed WO3 Hole Extraction Layer, Adv. Energy Mater., 2012, 2(12), 1433-1438. 

Many authors have reported different approaches for incorporation of different metallic NPs in organic solar cells (OSCs) i.e. in the photoactive layer, in the hole transport layer (HTL), at the HTL/photoactive layer interface and at the ITO/HTL interface. Fig. 6 shows the schematic design describing these different approaches. We have reviewed the detail literature of photovoltaic performance parameters of bulk heterojunction organic/polymer solar cell. Table 1, 2, 3, 4 summarizes the state of the art reports i.e., open circuit voltage (Voc), short circuit current density (jsc), fill factor (FF) and power conversion efficiency (ti) of plasmonic enhanced OSC devices with NPs embedded between interfacing layers, NPs in the hole conducting layers, combination of different NPs and NPs in the photoactive layer, respectively. 

The fill factor (FF), defined as Ima.xVma.x/IScVoc, is 0.25. The relatively low FF may be explained by recombination of charges at the ITO electrode. The present values of Isc and Voc are significantly enhanced in comparison with the device characteristics of a related Ceo-oligophenylenevinylene dyad [102] and quite similar to those previously reported for 7r-conjugated polymer/fullerene solar cells [115], although there has been considerable progress in energy conversion efficiencies of these devices recently [116]. 

Kietzke et al. have shown for bilayer solar cells based on M3EH-PPV and several acceptor polymers with varying electron affinities and the fullerene derivative PCBM that the open circuit voltage is linearly related to the respective LUMO levels [225]. While CN-PPV-PPE acceptors resulted in an increased open circuit voltage of about 1.5 V, the fill factor and photocurrent were smaller than those for CN-ether-PPV [225]. 

Keywords Solar cells, organic photovoltaics (OPVs), quantum confinement effect (QCE), conjugated polymers, nanocomposites, blends, quantum dots (QDs), nanocrystals, nanorods, carbon nanotubes (CNTs), graphene, nanoparticles, alternating copolymers, block copolymers, exdton diffusion length, short-circuit current, open-circuit voltage, fill factor, photoconversion efficiency, in-situ polymerization... 

Facchetti, A., Pignataro, B., and Loi, M A. (2011) Role of photoactive layer morphology in high fill factor all-polymer bulk heterojimction solar cells. /. Mater. Chem., 21, 5891-58%. 

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