Device band diagram

FIG. 3.35. Experimental J—V characteristics of an ITO/PEDOT PSS/PCBM/Au injection limited electron current (triangles) and calculated space charge limited hole current in OC4C10-PPV (circles) for a thickness of L = 170 nm and temperature T = 290 K. The inserted figure represents die device band diagram under the flat band condition of a bulk heterojunction solar cell using Au as a top electrode [65]. 

Figure 15-10. Schematic band diagrams for single-layer conjugated polymer devices at various values of forward bias. Forward bias is defined with respect lo ITO.

FIG. 73. Schematic cross seclion of a iriple-junclion u-Si H subsirale solar cell on stainless steel (a), and the corresponding schematic band diagram (b). (From R. E. I. Schropp and M. Zeman. "Amorphous and Microcrystalline Silicon Solar Cells—Modeling. Materials and Device Technology, Kluwer Academic Publishers. Boston. 1998, with permission.)... 

Materials with large E ex values would not be indicated for e.g., photovoltaic devices, since the photogeneration of charge carriers would be inefficient, but could in principle be used as light emitting diodes. Section 4.2 will show examples of the experimental determination of the band diagrams of selected organic semiconductors. El is usually obtained from o vs. T measurements, since a oc ... 

Fig. 29 (a) Architecture of graphene based OLED. (b) Energy band diagram of the device. (Reprinted with permission from [260])... 

Figure VII-3 Band diagram of a polymer LED. At zero bias, the Fermi level must be constant across the device. The asymmetry of the metal work functions causes the energy bands in the polymer to be tilted and results in a built-in electric field, which leads to the photovoltaic effect. With a forward bias, electrons and holes tunnel across the barrier into the TT and tt bands, respectively.

Fig. 11.15 Energy band diagram for two-junction photovoltaic device. (After ref. [69])...

Fig. 1. Device sandwich - type structure and band diagrams of the Co0 diode.

Optical characteristics and the energy band diagram of CuPc and BPPC. (a) Absorption spectra of CuPc and BPPC for vacuum deposited device and (b) energy band diagram of the single heterostructured CuPc and BPPC OPD. 

Figure 5.2 Energy band diagram of donor-acceptor (D-A) polymer cell, showing six steps associated in device operation. (1) Photon absorption (ij ) (2) exciton generation (r ) ...

Figure 5.13 (a) Device structure of solar cells, (b) Band diagram for P3HT/s-SWCNTs interfaces. The SWCNT energy levels depend on the s-SWCNT diameter distribution. The SWCNT values were obtained from LDA density functional theory calculations, in which the nanotube electronic gaps were slightly underestimated [147,148]. Reprinted (adapted) with permission from Ref. [145]. Copyright (2011) American Chemical Society. 

Fig. 7.27 PEC-PEC tandem water splitting device with band diagram showing photogenerated eleebons and holes...

In Figure 13.15c, the device structure of the CdS/P3HT NW-based hybrid solar cell device is schematically illustrated together with the corresponding flat band diagram (Figure 13.15d). 

Figure 4.3.5. A simplified energy band diagram of an n-type EIS device which has an applied voltage E such that the semiconductor oxide interface is in the inversion regime [shown by crossing of Ef and ( /) ] leading to a buildup of holes at the interface. Two energy scales are shown, one referenced to an electron at infinity (e ) and the other referenced to the saturated calomel electrode (SCE). The surface potential the voltage drop across the insulator, Vj, and the Fermi levels of the reference electrode, the semiconductor under an applied voltage E, and the intrinsic semiconductor [(Ef) t, Ef, and (Ef)i respectively] are all shown. (After Diot et al. [1986].)...

FIGURE 23 Band diagram of an EL device with an ETL and charge accumulation due to hole blocking by the ETL [141]. 

The operation of the device under forward bias may be imderstood using a simple band diagram (Fig. 2a). The anode and cathode materials are chosen to provide low barriers to electron and hole injection by matching the valence and... 

Fig. 2. Band diagram for (a) single-layer and (b) two-layer polymer EL devices (ETL electron transporting layer).

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