Porphyrin Sensitizers with Donor Structural Engineering for Superior Performance Dye‐Sensitized Solar Cells and Tandem Solar Cells for Water Splitting Applications

Abstract

Zn(II)–porphyrin sensitizers, coded as SGT‐020 and SGT‐021, are designed and synthesized through donor structural engineering. The photovoltaic (PV) performances of SGT sensitizer‐based dye‐sensitized solar cells (DSSCs) are systematically evaluated in a thorough SM315 as a reference sensitizer. The effect of the donor ability and the donor bulkiness on photovoltaic performances is investigated for establishing the structure–performance relationship in the platform of porphyrin‐triple bond‐benzothiadiazole‐acceptor sensitizers. By introducing a more bulky fluorene unit to the amine group in the SM315, the power conversion efficiency (PCE) is enhanced with the increased short‐circuit current (Jsc) and open‐circuit voltage (Voc), due to the improved light‐harvesting ability and the efficient prevention of charge recombination, respectively. As a consequence, a maximum PCE of 12.11% is obtained for SGT‐021, whose PCE is much higher than the 11.70% PCE for SM315. To further improve their maximum efficiency, the first parallel tandem DSSCs employing cobalt electrolyte in the top and bottom cells are demonstrated and an extremely high efficiency of 14% is achieved, which is currently the highest reported value for tandem DSSCs. The series tandem DSSCs give a remarkably high Voc value of >1.83 V. From this DSSC tandem configuration, 7.4% applied bias photon‐to‐current efficiency is achieved for solar water splitting.

Synthesis, Spectral, Electrochemical and Photovoltaic Studies of A3B Porphyrinic Dyes having Peripheral Donors

“…[31] The introduction of bulky peripheral groups such as t-butylphenyl, o-alkoxy and mesityl enhance the photovoltaic performance with fewer number of donor groups. [34] From all these observations it is clear that high PCE for porphyrin dyes could be achieved by (i) peripheral modification of the porphyrin structure for wide-band absorption and tuning of energy levels, (ii) enhanced push-pull effects from donor moiety to acceptor moiety within the sensitizer, and (iii) the choice of bridge (linker) connecting the porphyrin to the semiconductor surface. [20,32,33] Recently, a new set of push-pull zinc porphyrin sensitizers revealed an impressive PCE of 13-14 %.…”

“…[20,32,33] Recently, a new set of push-pull zinc porphyrin sensitizers revealed an impressive PCE of 13-14 %. [34] From all these observations it is clear that high PCE for porphyrin dyes could be achieved by (i) peripheral modification of the porphyrin structure for wide-band absorption and tuning of energy levels, (ii) enhanced push-pull effects from donor moiety to acceptor moiety within the sensitizer, and (iii) the choice of bridge (linker) connecting the porphyrin to the semiconductor surface. Sadly, the synthesis of high performance porphyrinic dyes involves multistep procedure with lower reaction yields resulting higher cost of DSSCs.…”

Tellurium-Doped, Mesoporous Carbon Nanomaterials as Transparent Metal-Free Counter Electrodes for High-Performance Bifacial Dye-Sensitized Solar Cells

“…This CV result was well-matched with the results of the other electrochemical analyses mentioned above. Based on the electrochemical analysis and various in-depth evaluations of TeMC CEs, the electrocatalytic ability of TeMC CEs was evaluated in an actual DSSC device employing the SM315 [39] sensitizer and the cobalt electrolyte [Co(bpy) 3 2+/3+ ]. Before fabricating the bifacial devices, we first confirmed the current-voltage (J-V) performance of the DSSC with the different TeMC CEs loading amounts.…”

Energy-Yielding Mini Heat Thermocells with WS2 Water-Splitting Dual System to Recycle Wasted Heat

“…2,3 Electrolytes are the most important and essential components in all types of batteries, including dyes-sensitive solar cells and water-splitting solar cells. 4,5 Among all gas molecules, hydrogen has the lightest molecular weight (2 g/mol) and highest energy density (enthalpy of −286 kJ/mol), which make it unreplaceable in green energy generation and conversion industry. 6,7 The most powerful device for hydrogen generation is hydrogen water-splitting cells.…”