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We demonstrate a monolithic perovskite/CIGS tandem solar cell with a certified power conversion efficiency (PCE) of 24.2%. The tandem solar cell still exhibits photocurrent mismatch between the subcells thus optical simulations are used to determine the optimal device stack. Results reveal a high optical potential with the optimized device reaching a short-circuit current density of 19.9 mA cm$^{−2}$ and 32% PCE based on semiempirical material properties. To evaluate its energy yield, we first determine the CIGS temperature coefficient, which is at −0.38% K$^{−1}$ notably higher than the one from the perovskite subcell (−0.22% K$^{−1}$), favoring perovskite in the field operation at elevated cell temperatures. Both single-junction cells, however, are significantly outperformed by the combined tandem device. The enhancement in energy output is more than 50% in the case of CIGS single-junction device. The results demonstrate the high potential of perovskite/CIGS tandem solar cells, for which we describe optical guidelines toward 30% PCE.

V zaključni nalogi smo numerično analizirali optimalno delitev razpoložljivega volumskega pretoka reke skozi hidroelektrarno in definirali aproksimacijsko funkcijo optimalnega izkoristka in moči v odvisnosti od volumskega pretoka in razpoložljive višine v hidroelektrarni. Numerični algoritem smo aplicirali na praktičnem primeru HE Brežice ter ugotovili, da lahko optimalna delitev pretoka skozi hidroelektrarno opazno poveča končni energijski izplen. Optimalen način obratovanja smo grafično in analitično primerjali z referenčnima primeroma delitve pretoka in s tem potrdili pravilnost numeričnega algoritma. In the final assignment, we preformed a numerical analysis of the optimal division of the availahle volume flow of the river through the hydroelectric power plant, furthermkore we defined the approximation function that describes the optimal efficiency and power output depending on the volume flow and the available height in the hydroelectric power plant. We applied the numerical algorithm to the practical example of HPP Brežice and found that the optimal distribution of the flow through the hydroelectric power plant can significantly increase the final energy yield. Finally, we graphically and analytically compared the optimal mode of operation with two reference cases of flow distribution and thereby confirmed the correctness of the numerical algorithm.