Yanyan Duan

Transparent Metal Selenide Alloy Counter Electrodes for High‐Efficiency Bifacial Dye‐Sensitized Solar Cells

The exploration of cost-effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye-sensitized solar cells (DSSCs). Transparent counter electrodes based on binary-alloy metal selenides (M-Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution-based method and employed in efficient bifacial DSSCs. Owing to superior charge-transfer ability for the I(-) /I3 (-) redox couple, electrocatalytic activity toward I3 (-) reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30 % and 4.63 % for Co0.85 Se, 7.85 % and 4.37 % for Ni0.85 Se, 6.43 % and 4.24 % for Cu0.50 Se, 7.64 % and 5.05 % for FeSe, and 9.22 % and 5.90 % for Ru0.33 Se in comparison with 6.18 % and 3.56 % for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels.

Enhanced dye illumination in dye-sensitized solar cells using TiO2/GeO2 photo-anodes

Dye illumination is a core factor in enhancing the electron density in the conduction band of TiO2 nanocrystallites and therefore also affects the power conversion efficiency of dye-sensitized solar cells (DSSCs). We investigated the use of anodes composed of TiO2/GeO2 nanocrystallites in DSSCs with the aim of increasing the power conversion efficiency. The interference effects from light reflected from the TiO2/GeO2 and GeO2/electrolyte interfaces significantly enhanced the intensity of the light used to illuminate the dye. We found an optimum power conversion efficiency of 7.91% (measured under standard AM 1.5 test conditions) in the DSSC using TiO2/0.5 wt% GeO2 nanocrystallites compared with 6.05% in a DSSC based on pure TiO2, an efficiency enhancement of 30.7%. This strategy provides a new opportunity for the fabrication of highly efficient DSSCs and the efficiency could be further improved using scalable techniques and components.

Platinum Alloy Tailored All-Weather Solar Cells for Energy Harvesting from Sun and Rain

Solar cells that can harvest energy in all weathers are promising in solving the energy crisis and environmental problems. The power outputs are nearly zero under dark conditions for state-of-the-art solar cells. To address this issue, we present herein a class of platinum alloy (PtMx , M=Ni, Fe, Co, Cu, Mo) tailored all-weather solar cells that can harvest energy from rain and realize photoelectric conversion under sun illumination. By tuning the stoichiometric Pt/M ratio and M species, the optimized solar cell yields a photoelectric conversion efficiency of 10.38 % under simulated sunlight irradiation (AM 1.5, 100 mW cm-2 ) as well as current of 3.90 μA and voltage of 115.52 μV under simulated raindrops. Moreover, the electric signals are highly dependent on the dripping velocity and the concentration of simulated raindrops along with concentrations of cation and anion.

Solid-state dye-sensitized solar cells from poly(ethylene oxide)/polyaniline electrolytes with catalytic and hole-transporting characteristics

The pursuit of cost-effective and efficient solid-state electrolytes is a persistent objective for dye-sensitized solar cells (DSSCs). Herein, we present the experimental design of iodide/triiodide (I−/I3−)-incorporated poly(ethylene oxide)/polyaniline (PEO/PANi) solid-state electrolytes, aiming at expanding the catalytic event of I3− reduction from the electrolyte/counter electrode interface to both the interface and electrolyte system and shortening the charge diffusion path length. Except for I− species, the conjugated PANi is also responsible for dye regeneration and hole transfer to the counter electrode. A DSSC with (I−/I3−)-incorporated PEO/1.0 wt% PANi electrolyte yields a maximum efficiency of 6.1% in comparison with 0.8% obtained from a PANi-free electrolyte-based solar cell and 0.1% for a PANi-based solar cell.

Interfacial engineering of hybridized solar cells for simultaneously harvesting solar and rain energies

Photovoltaics have been regarded as a promising solution to energy and environmental problems, however the state-of-the-art photovoltaics cannot harvest energy or therefore generate electricity in completely dark conditions. To address this issue, we present here the realization of physical proof-of-concept hybridized solar cells by tailoring photovoltaics with polyaniline and its derivates for harvesting energy from the sun and rain. Through interfacial engineering, the optimized polyaniline–graphene/PtCo tailored solar cell yields a photo efficiency of 9.09% under air mass 1.5 illumination and a dark efficiency of up to 25.58% as well as current and voltage under the stimulus of real rain. This work may enable scientists to explore advanced all-weather solar cells revolutionizing photovoltaics.