Solar cells single layer

There are four different types of organic or organic/inorganic hybrid solar cells single-layer, bilayer, bulk heterojunction (BHJ), and dye-sensitized. The basic operation of each device type is described below. 

In two-component charge transfer systems, such as in the bulk-heterojuncdon solar cells presented here, deviations of the V,K. from the results of pristine single layer or bilayer devices are expected for two reasons first, some pan of the available difference in electrochemical energy is used internally by the charge transfer to a lower energetic position on the electron acceptor second, the relative posi-... 

Electrodeposition of copper indium disulfide (CulnS2) has been reported [180-182], In a typical instance, single-phase polycrystalline CuInS2 thin films composed of 1-3 fim sized crystallites were grown on Ti by sulfurization of Cu-ln precursors prepared by sequentially electrodeposited Cu and In layers [183]. In this work, solar cells were fabricated by electrodepositing ZnSe on CuInS2. Cyclic... 

A single layer of a micro PS film on a silicon substrate always reduces its reflectivity, because of its lower refractive index compared to bulk Si. Hence micro and meso PS films of a thickness around 100 nm have been proposed as anti-reflec-tive coatings for solar cells [Pr8, Gr9, Pol, Bi4, Scl8, StlO]. 

A particular buffer layer experiment, carried out by Nguyen et al. [154, 155], is shown in Fig. 4.34. Two different combinations of chemical bath deposited CdS and Inx(OH,S)y buffer layers were used to fabricate Cu(In,Ga)Se2 thin-film solar cells. The experiment was defined in order to identify the interface that leads to poor efficiencies if single Inx(OH,S)y buffer layers are used. The type A arrangement of the two buffer layers with a Cu(In,Ga)Se2/CdS and an Inx(OH,S)y/ZnO interface results in poor efficiencies, while type B arrangement with a Cu(In,Ga)Se2/Inx(OH,S)y and a CdS/ZnO interface results in a high efficiency. This observation strongly suggests that the interface between Inx(OH,S)y and ZnO limits the efficiency. 

Here we describe the layer structure for single junction as well as for tandem solar cells consisting of a-Si H and pc-Si l I. Further, this section will deal with the stability of silicon thin film solar cells and the possibility to reduce degradation by special design. 

Fig. 8.4. Layer structure of single junction n-i-p (substrate) and p-i-n (superstrate) solar cells. Also included is an amorphous/microcrystalline tandem solar cell structure...

The best stabilized cell efficiencies on ZnO Al obtained at the FZJ in a PECVD reactor for 30 x 30 cm2 substrates were 8.0, 8.9, and 11.2% for a-Si H p-i-n, )LLc-Si H p-i-n, and a-Si H/)j,c-Si H tandem cells, respectively [152], The best initial efficiency for pc-Si H single junction solar cells was achieved by Mai et al., who reached 10.3% for an absorber layer thickness of 1.6 J,m, which was deposited at a high deposition rate of 11 As-1 [153], Initial aperture area module efficiencies of 10.8 and 10.6% were achieved for a-Si H/pc-Si H tandem modules with an aperture area of 8 x 8 and 26 x 26 cm2, respectively [154,155]. The efficiency of the small area module stabilized at an efficiency of 10.1% after lOOOh of light soaking as confirmed by the National Renewable Energy Laboratory (NREL, see Fig. 8.29). 

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. 

---