One-Pot Solvothermal in Situ Growth of 1D Single-Crystalline NiSe on Ni Foil as Efficient and Stable Transparent Conductive Oxide Free Counter Electrodes for Dye-Sensitized Solar Cells

Abstract

One-dimensional single-crystal nanostructural nickel selenides were successfully in situ grown on metal nickel foils by two simple one-step solvothermal methods, which formed NiSe/Ni counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The nickel foil acted as the nickel source in the reaction process, a supporting substrate, and an electron transport "speedway". Electrochemical testing indicated that the top 1D single-crystal NiSe exhibited prominent electrocatalytic activity for I reduction. Due to the metallic conductivity of Ni substrate and the outstanding electrocatalytic activity of single-crystal NiSe, the DSSC based on a NiSe/Ni CE exhibited higher fill factor (FF) and larger short-circuit current density (J) than the DSSC based on Pt/FTO CE. The corresponding power conversion efficiency (6.75%) outperformed that of the latter (6.18%). Moreover, the NiSe/Ni CEs also showed excellent electrochemical stability in the I/I redox electrolyte. These findings indicated that single-crystal NiSe in situ grown on Ni substrate was a potential candidate to replace Pt/TCO as a cheap and highly efficient counter electrode of DSSC.

A detailed investigation on the performance of dye-sensitized solar cells based on reduced graphene oxide-doped TiO2 photoanode

“…Graphene (GN) has a two-dimensional layered nanostructure composed of sp 2 -hybridized carbon atoms and attracts great deal of attentions due to its unique physical and electrical characteristics, and high specific surface area [14][15][16]. Preparation of graphene-TiO 2 (GN-TiO 2 ) or reduced graphene oxide-TiO 2 (RGO-TiO 2 ) nanohybrid material as the photoanode in DSSCs is a new hot spot in the research of DSSCs in recent years [17][18][19][20][21][22][23][24].…”

An Interconnected Ternary MIn2S4 (M=Fe, Co, Ni) Thiospinel Nanosheet Array: A Type of Efficient Platinum‐Free Counter Electrode for Dye‐Sensitized Solar Cells

“…EIS measurements of dummy cells were used to further confirm the charge transfer kinetics of different CEs (Figure 3c). According to the Randles-type circuit (inset of Figure 3c), [25,26] EIS curves were fitted by the Zview software and the fitted results are listed in the Supporting Information, Table S2. Theo hmic series resistance (R S )i sa ssigned to the intercept on the real axis and the reduced R S is expected to reduce overall device resistance.T he semicircles at high frequency and low frequency can be attributed to the charge transfer resistance (R CT )a tt he interface of CE/electrolyte and the Nernst diffusion impedance (W)i nt he electrolyte, respectively.…”

“…j J ox /J red j ratios for different CEs were calculated and in an order of CoIn 2 S 4 (1.01) < NiIn 2 S 4 (1.20) < FeIn 2 S 4 (1.22), indicating areversible order of CoIn 2 S 4 > NiIn 2 S 4 > FeIn 2 S 4 ,and giving conversion rate order (from I 3 À to I À )o fC oIn 2 S 4 > NiIn 2 S 4 > FeIn 2 S 4 .T he catalytic activity of binary references complies with the order of CoS 2 > NiS/Ni 3 S 4 > FeS 2 > In 2.77 S 4 (Supporting Information, Figure S7), which is lower than that of corresponding ternary MIn 2 S 4 CE (M = Fe,C o, Ni). [25,26] According to the Equation (1), the D n was calculated for all CEs, [25,26] where K [25,26] According to the Equation (1), the D n was calculated for all CEs, [25,26] where K…”

“…According to the CV measurements of different CEs at different scan rates (Supporting Information, Figure S8), one can conclude that the J red is the linear function of the square root of scan rate (Figure 3b), indicating the I 3 À reduction is mainly controlled by the ionic diffusion process in the electrolyte. [25,26] According to the Equation (1), the D n was calculated for all CEs, [25,26] where K…”

“…[25,26] Thea ttenuation trend of R CT (FeIn 2 S 4 > NiIn 2 S 4 > CoIn 2 S 4 )i ndicates an inverse order of charge transfer rate and catalytic activity of CEs. [25,26] The W follows an order of FeIn 2 S 4 > NiIn 2 S 4 > CoIn 2 S 4 ,w hich can be evidenced from the D n with inverse order. Thec onstant phase element (CPE) refers to the capacitance with non-ideal frequencya tt he interface of CE/electrolyte.…”