Incident photon to collected electron

Two devices are prepared. In the case of the device A, the incident photon-to-collected electron conversion efficiency (IPCE) exceeds 80% from 410 to 590 nm, reaching the maximum of 93% at 530 nm. The short-circuit photocurrent density (/sc), open-circuit photovoltage (Voc), and fill factor (FF) of device A with an acetonitrile-based electrolyte under an irradiance of AM 1.5 G full sunlight are 14.33 mA cm-12, 734 mV, and 0.76, respectively, yielding an overall conversion efficiency (jf) of 8.0%. The photovoltaic parameters of device B with a solvent-free ionic liquid electrolyte are 14.06 mA cm 12, 676 mV, 0.74, and 7.0%, respectively. 

Fig. 22 Optical transmission spectra of 100-nm-thick MDMO-PPV PCBM (1 4 by wt.) films spin cast onto glass substrates from either toluene (dashed line) or chlorobenzene (solid line) solutions (a). Incident photon to collected electron (IPCE) spectra (b) and current-voltage characteristics (c) for photovoltaic devices using these films as the active layer. (Reprinted with permission from [34], 2001, American Institute of Physics)...

The spectral responsivity measurements yield the number of collected electrons per incident photon at each wavelength. Hence it is also called incident photon to collected electron (IPCE), or external quantum efficiency (EQE) measurement. IPCE is given as... 

This device gave an incident-photon-to-collected-electron efl ciency of 12.1% and a power conversion efl ciency of 0.8% under monochromatic irradiation [279]. Single-polymer-layer photovoltaic devices using polybithiophene (PBT) thin films and fluorine-doped tin oxide substrate have also been constructed (Fig. 7.22). As well as the difference in the work functions of the electrodes, the high organization of the molecular dipoles in PBT yielded an open-circuit potential of 2 V when an aluminum top contact was used [279]. 

Incident Photon to Current Efficiency IPCE, also called external quantum efficiency, is the ratio of electrons collected at the terminals to incident... 

Schematic of a nipi structure (left). Very thin alternating layers of n- and p-doped GaAs form a sandwich-like structure. When an incident photon creates an electron-hole pair, the holes are swept into the p-layer and the electrons are swept into the n-layer by the fields created by the junctions. Since there are few minority carriers to recombine with, a larger fraction of these charges can be collected.

Recently, uniform Filins with high concentrations of Cwl were cast from 1,2-dichlorobenzene solutions containing up to 1 4 weight ratio MEH-PPV [110]. For devices made from these high concentration blends, charge collection efficiencies around //,.=26% (electron/incident photon) and power conversion efficiencies around tjc-2.5% (electrical power out/incident light power) have been realized. 

PMTs contain a photosensitive cathode and a collection anode that are separated by electrical electrodes called dynodes, which provide electron multiplication or gain. The cathode is biased negatively by 400-2500 V with respect to the anode. An incident photon ejected by the photocathode strikes the first dynode... 

Fig. 4.9. Schematic of photoemission experiments, A beam of incident photons with energy ftto induces electrons to emit from the sample. The photoelectrons are collected by the velocity analyzer and the electron detector at angles 9 and

The photoelectric cross-section o is defined as the one-electron transition probability per unit-time, with a unit incident photon flux per area and time unit from the state to the state T en of Eq. (2). If the direction of electron emission relative to the direction of photon propagation and polarization are specified, then the differential cross-section do/dQ can be defined, given the emission probability within a solid angle element dQ into which the electron emission occurs. Emission is dependent on the angular properties of T in and Wfin therefore, in photoelectron spectrometers for which an experimental set-up exists by which the angular distribution of emission can be scanned (ARPES, see Fig. 2), important information may be collected on the angular properties of the two states. In this case, recorded emission spectra show intensities which are determined by the differential cross-section do/dQ. The total cross-section a (which is important when most of the emission in all direction is collected), is... 

The parameter that directly measures how efficiently incident photons are converted to electrons is the IPCE. The wavelength-dependent IPCE term can be expressed as a product of the quantum yield for charge injection ( ), the efficiency of collecting electrons in the external circuit (17), and the fraction of radiant power absorbed by the material or light harvesting efficiency (LHE), as represented by Equation 17.8 ... 

Surface plasmon resonance (SPR) biosensors exploit special electromagnetic waves-surface plasmon-polaritons-to probe interactions between an analyte in solution and a biomolecular recognition element immobilized on the SPR sensor surface. A surface plasmon wave can be described as a light-induced collective oscillation in electron density at the interface between a metal and a dielectric. At SPR, most incident photons are either absorbed or scattered at the metal/dielectric interface and, consequently, reflected light is greatly attenuated. The resonance wavelength and angle of incidence depend upon the permittivity of the metal and dielectric. 

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