Single-Layer Polymer Cells

A single layer solar cell is the simplest solar cell. It is essentially a Schottky diode with a polymer layer sandwiched between two metal electrodes. Several groups have... 

FIGURE 8.3 Schematic drawing of the operation of a single-layer polymer solar cell. 

Figure 6.1 Four device architectures of conjugated polymer-based photovoltaic cells (a) single-layer polymer PV cell (b) bilayer polymer PV cell (c) disordered bulk heterojunction (d) ordered...

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. 

Aside from dye-based cells, a good deal of study has been devoted to photovoltaic effects in polymer-based devices. Single-layer sandwich-type devices composed of aluminum—polyphenjienevinjiene—ITO have been fabricated with solution-cast polymer layers of These devices display... 

Fig. 12 Examples of device architectures of conjugated polymer-based photovoltaic cells a single layer b bilayer c disordered bulk heterojunction d ordered bulk heterojunction. (Reproduced with permission from [71], 2005, American Chemical Society)...

The application of MWNTs in the field of polymer solar cells was presented by Ago et al. [311]. Here, a layer of CNTs served as a replacement for the common ITO hole-collecting electrode in a single layer PPV/Al diode (Fig. 64). The authors related the twofold enhancement of the EQE observed with the MWNT based device to the formation of a complex network with an increased interface area between MWNTs and PPV, in addition to a stronger built-in electric field as a result of the higher work function of MWNTs compared to the standard ITO electrode [311,312]. To determine whether electron or energy transfer processes dominate within MWNT PPV blends, their photophysical properties were studied by photoluminescence and PIA spectroscopy. The results confirmed nonradiative energy transfer from PPV singlet excitons to the MWNTs as the main electronic interaction [313]. 

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