Achieving a broad-spectrum photovoltaic system by hybridizing a two-stage thermoelectric generator

A novel solar hybrid system (SHS) that couples a two-stage thermoelectric generator (TTEG) to a dye-sensitized solar cell (DSSC) is put forward to broadbandly capture the inlet sunlight, in which the TTEG considers Thomson effect as well as Peltier effect and Seebeck effect. The mathematical relationship between the TTEG dimensionless operating electric current and the DSSC operating electric current is determined. Theoretical calculation indicates the maximum power output density (MPOD) and maximum energy efficiency (MEE) of DSSC are, respectively, 77.82 W m(-2) and 4.94%, and the MPOD and MEE of SHS are, respectively, improved by 4.33% and 64.25% in comparison with the single DSSC. Moreover, the MPOD and MEE of SHS with Thomson effect are 1.49% and 0.05% smaller than that without Thomson effect, respectively. Exhaustive parametric studies are conducted to examine the dependence of SHS performance on comprehensive designing parameters and operating conditions, including temperature difference between operating temperature and environment temperature, Schottky barrier, thickness of porous nano-TiO2 semiconductor film, thermoelectric element (TEE) number ratio of top stage to bottom stage, total number of TEE, length and cross-sectional area of semiconductor legs. The obtained results are helpful for designing and optimizing such an actual SHS.