Acceptor polymers

FIGURE 5.3 Structures of typical n-type conducting polymers used as acceptors in polymer solar cells. Reproduced with permission from reference Facchetti, A, 2013. Poiymer donor-polymer acceptor (all-polymer) solar cells. Mater. Today 16, 123-132. Copyright 2013, Elsevier Ltd. 

Facchetti, A., 2013. Polymer donor-polymer acceptor (all-polymer) solar cells. Mater. Today 16,123-132. 

Early studies of ADP-ribose polymer metabolism concluded that PARG was unable to remove the protein proximal ADPR residue from acceptor proteins. This led to the isolation of an ADP-rlbosyl protein lyase that catalyzes removal of the protein proximal ADPR residue linked to the acceptor protein. Although this enzyme was discovered many years ago, it has received very little attention and consequently its structure function relationships and role in ADPR polymer metabolism are still poorly understood. Additional questions have been raised by recent studies that indicate that PARG can catal removal of protein proximal ADPR residues linked to carboxylate groups of histone HI. It is possible that the property of both enzymes to catalyze removal of these residues represents redundancy in function or that specific polymer acceptor proteins require different enzymes to catalyze removal. 

A. Facchetti, Polymer Donor-Polymer Acceptor (All-Polymer) Solar Cells. Mater. Today 2013,16,123-132. 

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. 

Figure 1 illustrates the inactivation of the DNA dependent catalytic activity of poly-(ADP-ribose) polymerase, which follows typical first-order kinetics (tl/2 - 0.518 h, Kj = 1.34 h ). Figure 2 shows the decrease in the binding of the lysine modified enzyme compared to the native enzyme (both labeled with to DNA cellulose from K ) = 15.7 1 to Kp 47.7 2 nM. Figure 3 illustrates that the modified enzyme can serve as polymer acceptor, when incubated with native polymerase, and the quantity of polymer protein adducts is proportional to the amount of lysine modified enz5nne protein. 

At the polymer/acceptor interface, the arrangement of the polymer and acceptor relative to each other can have a profound effect on charge dissociation [197,198,209]. The heterojunction interface complexity effectively limits the characterization techniques to those capable of providing angstrom-level resolution. As mentioned before, solid-state NMR is one of the few techniques that fit this requirement. 

Many other carbazole polymer/acceptor combinations have appeared in the patent literature, but none have been studied as extensively as the PVK/TNF complex. 

In the hope of addressing these issues, PSCs based on non-fullerene acceptors have been developed. In general, there are two alternatives for the replacement of fullerenes in PSCs. One choice is a polymer acceptor and the other is a small molecular acceptor. Both the polymer and small molecule alternatives have easily tunable energy levels and potentially much greater light absorption properties than fullerenes. The challenge is to improve the PSC performance to a level comparable to that of polymer -fullerene PSCs. The best efficiency levels achieved for PSCs based on polymers or small molecular acceptors are about which are far behind... 

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