Low-Temperature Chemical Sintered TiO2 Photoanodes Based on a Binary Liquid Mixture for Flexible Dye-Sensitized Solar Cells

Abstract

A chemically sintered and binder-free paste of TiO 2 nanoparticles (NPs) was prepared using a binary-liquid mixture of 1octanol and CCl 4 . The 1:1 (v/v) complex of CCl 4 and 1-octanol easily interacted chemically with the TiO 2 NPs and induced the formation of a highly viscous paste. The as-prepared binary-liquid paste (P BL )-based TiO 2 film exhibited the complete removal of the binary-liquid and residuals with the subsequent low-temperature sintering (~150ºC) and UV-O 3 treatment. This facilitated the fabrication of TiO 2 photoanodes for flexible dye-sensitized solar cells (f-DSSCs). For comparison purposes, pure 1-octanol-based TiO 2 paste (P O ) with moderate viscosity was prepared. The P BL -based TiO 2 film exhibited strong adhesion and high mechanical stability with the conducting oxide coated glass and plastic substrates compared to the P O -based film. The corresponding low-temperature sintered P BL -based f-DSSC showed a power conversion efficiency (PCE) of 3.5%, while it was 2.0% for P O -based f-DSSC. The P BL -based low-and high-temperature (500ºC) sintered glassbased rigid DSSCs exhibited the PCE of 6.0 and 6.3%, respectively, while this value was 7.1% for a 500ºC sintered rigid DSSC based on a commercial (or conventional) paste.

Chemical sintering by chlorinated carbon compounds for flexible photoanodes of dye-sensitized photovoltaic cells

“…Subsequently, all the TiO 2 electrodes were immersed in a 0.5 mM N719 dye solution in ethanol for 18 h. To prepare CEs for DSSCs, chloroplatinic acid hexahydrate (H 2 PtCl 6 $6H 2 O) solution (10 mM) in 2-propanol was spin-coated on a glass/FTO substrate and sintered in an electrical muffle furnace at 450 °C for 20 min under ambient conditions. 36,37 For the systematic evaluation of low temperature processable TiO 2 pastes, three types of devices were prepared. First, conventional DSSCs with glass/FTO (for both the photoanode and CEs) were prepared using P(O) and P(BL).…”

“…It was reported that 1-octanol and CCl 4 could form a complex with a 1 : 1 ratio via hydrogen bonding (O-H/C1). [36][37][38][39][40] Thus, considering the structural similarities of CHCl 3 and C 2 Cl 4 with CCl 4 and the T b of the binary solvents, the 1 : 1 volume ratio of 1-octanol and CCs was chosen as the optimized composition for the preparation of low-temperature (#150 °C) processable TiO 2 pastes. Furthermore, we measured the viscosity of the 1-octanol and binary mixture and the corresponding P(O) and P(BL) pastes, as shown in Fig.…”

“…Various methods have been suggested for the fabrication of exible TiO 2 photoanodes under low-temperature processing conditions such as electrophoretic deposition, [7][8][9] spray deposition, [10][11][12][13][14] chemical vapor deposition, 15 pulsed laser annealing, 16 light annealing, 17,18 heat sink assisted annealing, 19,20 mechanical compression, [21][22][23][24] lioff transfer, 25,26 and chemical sintering. [27][28][29][30][31][32][33][34][35][36] Among these approaches, the chemical sintering method is shown to be more promising for the fabrication of low-temperature sintered exible TiO 2 photoanodes with a high thickness (>10 mm), strong adhesion, and improved interparticle connection.…”

“…Recently, we reported a highly viscous TiO 2 paste consisting of 1-octanol and carbon tetrachloride (CCl 4 ), with which a PCE of 6.0% was achieved for DSSCs upon sintering the photoanode at 150 °C. 36 We showed that the binary solvent mixtures prepared using a long alcoholic hydrocarbon chain with high boiling temperature and high viscosity (e.g., 1-octanol) were appropriate to form effective binder-free TiO 2 pastes for exible photoanode preparation in a low-temperature range. In this study, we further extended to use other chlorinated carbons (CCs), chloroform (CHCl 3 ) and tetrachloroethylene (C 2 Cl 4 ), as environmentally acceptable chemical sintering agents instead of CCl 4 .…”

A Comprehensive Review on Perovskite Solar Cells Integrated Photo‐supercapacitors and Perovskites‐Based Electrochemical Supercapacitors

“…[9,10] Next-generation PVs with high PCE are under research focus, such as perovskite solar cells (PSCs), organic solar cells (OSCs), dyesensitized solar cells (DSSCs), and quantum-dot sensitized solar cells (QDSSCs). [11][12][13][14] Among them, PSCs have recently attracted massive attention due to their cost-effectiveness and remarkably high PCE, achieved by low-cost and solution process fabrication. [15][16][17][18] For example, the PCE of PSCs has significantly improved from the first report with a PCE of 3.8 % in 2009 [19] to the current world-record PCE of 25.8 % for single junction PSCs, verified by the national renewable energy laboratory in 2023.…”