The quantum efficiency may be given either as a function of wavelength or as energy. If all photons of a certain wavelength are absorbed and the resulting minority carriers are collected, then the quantum efficiency at that particular wavelength is unity. The quantum efficiency for photons with energy below the band gap is zero. A quantum efficiency curve for an ideal solar cell is shown below.
Published online Oct Abstract Lytic polysaccharide monooxygenase LPMO represents a unique principle of oxidative degradation of recalcitrant insoluble polysaccharides.
Used in combination with hydrolytic enzymes, LPMO appears to constitute a significant factor of the efficiency of enzymatic biomass depolymerization. LPMO activity on different cellulose substrates has been shown from the slow release of oxidized oligosaccharides into solution, but an immediate and direct demonstration of the enzyme action on the cellulose surface is lacking.
Specificity of LPMO for degrading ordered crystalline and unordered amorphous cellulose material of the substrate surface is also unknown. We show by fluorescence dye adsorption analyzed with confocal laser scanning microscopy that a LPMO from Neurospora crassa introduces carboxyl groups primarily in surface-exposed crystalline areas of the cellulosic substrate.
Using time-resolved in situ atomic force microscopy we further demonstrate that cellulose nano-fibrils exposed on the surface are degraded into shorter and thinner insoluble fragments.
Also using atomic force microscopy, we show that prior action of LPMO enables cellulases to attack otherwise highly resistant crystalline substrate areas and that it promotes an overall faster and more complete surface degradation. Overall, this study reveals key characteristics of LPMO action on the cellulose surface and suggests the effects of substrate morphology on the synergy between LPMO and hydrolytic enzymes in cellulose depolymerization.
Multiple chains are organized spatially into a densely packed crystalline material 12.
More disordered parts of the cellulose, which are also present in natural or technologically processed substrates, are usually called amorphous. In contrast to amorphous regions, crystalline cellulose is highly resistant to degradation. The low efficiency of its conversion threatens the commercial viability of biofuels or base chemicals produced from cellulosic biomass 34.
Cellulases represent the current paradigm for enzymatic cellulose degradation through hydrolytic depolymerization 14. Cellulases comprise internally chain-cleaving endoglucanases EG 4 and processively chain end-cleaving cellobiohydrolases CBHs as their main activities 1.
Different cellulolytic activities operate synergistically; that is, combinations of enzymes are hydrolytically more efficient than expected from the sum of their individual activities 5— 7.
Cellulase synergism originates from the dynamic interplay between endo- and exo-modes of cellulose chain cleavage as well as from complementary enzyme specificities for degrading crystalline and amorphous cellulose material Fig. Cellulases adsorb strongly to cellulose 710and their combined action on the solid surface is reflected by strong three-dimensional degradation where amorphous material is degraded at higher rates than crystalline structures 8It is known that the potential induced degradation (PID) stress of conventional p-base solar cells affects power, shunt resistance, junction .
Furthermore, this low-bandgap PVSC reached an external quantum efficiency (EQE) of more than 70% in the wavelength range of – nm, the essential infrared spectral region . The results showed that the efficiency degradation of solar cells by indirect PECVD method is up to −%, which is out of the IEC standard and is significantly more severe than by the direct PECVD method (−%).
The internal quantum efficiency (IQE) of a. SHUKLA et al: Assuming a perfect diffusive surface for EL emission, the luminous flux φ(λ) of the devices can be written as: reduction in degradation and introduction of impurities in the active layer.
We have compared the. The animation below shows the effect on surface recombination and diffusion length on the internal quantum efficiency of a solar cell. The emitter thickness is 1 µm, the base thickness is µm, the emitter diffusivity is 4 cm 2 s . The influence of O 2, CO 2, CO, N 2, H 2 and CH 4 on the stability of the quantum efficiency (QE) of a negative electron affinity gallium arsenide (GaAs) photocathode activated with caesium (Cs) and oxygen (O) has been demonstrated for the first time under an extremely high vacuum condition, a base pressure of × 10 −11 mbar, .