The design of electrochemical solar cells (SCs), including those composed of biological pigments is an actively developing direction of obtaining alternative energy. SCs were studied under different temperatures, light intensities and spectral conditions. Furthermore, to understand processes occurring in the SCs, investigations characterizing the efficiency and stability with regard to environmental factors are also required. For this aim, novel instrumentation for the investigation of environmental effects on photocurrent generated by SCs has been designed and constructed. The system can be a model, which reflects conditions required for effective and stable functioning of the solar cells. Preliminary results are shown for two types of solar cells with two photosensitizers: thylakoid membrane preparations and anthocyanin-enriched raspberry extracts. It was shown that electrogenic activity decreased by a half at 40 °C and returned back to the initial value under gradual cooling. Maximum current obtained from the thylakoid-based SC was 0.46 mA, while maximum current generated by the anthocyanin-based SC was 1.75 mA. The goal of this investigation is to find new ways to increase efficiency and stability of bio based SCs. In future, this measuring system can be used for investigation of solar cells based on long-wave forms of chlorophylls (Chls d and f) and components of the photosynthetic apparatus comprising these chlorophylls.

Biohydrogen has been regarded as carbon neutral fuel. Thus it possesses tremendous potential in energy sector. The present study deals with the potentiality of bio-augmented facultative anaerobic bacteria with obligate anaerobe for the improvement of H2 production. The co-culture strategy of Klebsellia pneumoniae and Clostridium acetobutylicum improved hydrogen yield by 37% and 18% respectively as compared to individual organism. COD removal efficiency was also observed higher in case of co-culture. Maximum H2 yield by this augmented system using cane molasses, starchy wastewater and distillery effluent were 9.47, 8.72 and 7.78 mol H2 kg-1 COD reduced respectively. The COD removal efficiency using different organic residues were in the range of 50–70%. Highest H2 production rate of 1125, 642 and 790 mL L-1 h-1 were observed by using cane molasses, starchy wastewater and distillery effluent respectively in CSTR. So, bio-augmented system could be helpful in realizing the goal of “waste to energy” concept.

The paper reviews the basic physical principles of improving the thermoelectric quality factor in nanostructured materials such as thin films, superlattices, whiskers, nanoscale structures, quantum wells, quantum wires. The physical fundamentals of optimizing such important parameters of thermoelectric materials as thermoelectric power, electrical resistivity, and thermal conductivity. We have conducted the analysis of the effect of Kapitsa grain-boundary thermal resistance, depending on the type of interfaces: coherent (the presence of elastic strains is possible), semicoherent (misfit dislocations are surrounded by elastic strains), and incoherent (the interaction between phases is minimal), shape and size of inclusions. The thermoelectric power in low-dimensional structures can be increased by changing the form of the density of states near the Fermi level or due to the effect of energy filtering of charge carriers. As part of the increase in the thermopower, the semimetal−semiconductor quantum transition in bismuth and carbonbased nanostructures is considered. The modulation doping of nanostructures allows one to achieve large values of the mobility of charge carriers at their very high concentration, which is demonstrated in the work on the example of superlattices of quantum dots based on silicon and germanium, as well as two-phase composites. Much attention is paid to the analysis of the experimental results, available in literature, which confirm the theoretical conclusions about the possibility of creating highly effective thermoelectric nanomaterials. The main approaches to obtaining nanostructures with the required size and distribution of nanoparticles are briefly considered.