Synergistic Effect of P5/HCl on the Performance Regulation of FDSSC Photoanode Sintered at Low Temperature

doi:10.16553/j.cnki.issn1000-985x.2025.0125

Abstract

Abstract: Aiming at the issue of insufficient interfacial adhesion of the TiO₂ film caused by the poor low-temperature tolerance （<150 ℃） of conductive polymer substrates in flexible dye-sensitized solar cells （FDSSC）， a three-step chemical sintering method was proposed for the first time to prepare TiO₂ film on conductive polymer substrat， Meanwhile， the ratio of P25-P100 TiO₂ slurry to P5/HCl binder was adjusted. Combined with XRD crystal structure analysis， SEM and TEM morphology characterization， flexible film bending test， and photoelectric performance test of FDSSC by electrochemical workstation， the influence of different ratio and bending radius on the comprehensive performance of FDSSC was discussed. The results show that when the ratio of P25-P100 slurry to P5/HCl binder is 4:1， a TiO₂ film with fewer agglomeration and crack defects is prepared. The photoelectric conversion efficiency （PCE） of the battery reaches 5.17%， which is 109.3% higher than that of the control group， while reducing the electron transmission impedance （R_ct2） and prolonging the electron transmission life （τ_n）. By studying the strain law and photoelectric properties under different bending radius （R=250~100 mm）， it is shown that the strain of the material shows a trend of “first increase and then slow” in the range of bending radius 250~100 mm， and the critical transition occurs between 175~100 mm.When R=100 mm， the battery still maintains 2.34% PCE （45.3% retention rate of the original state）.This study provides a new idea for the optimization of photoelectric-mechanical properties of FDSSC.

Key words: flexible; dye-sensitized solar cell; three-step chemical sintering method; bending test; TiO₂

CLC Number:

TM914.4

CHENG Pengyuan, SHEN Minwei, ZHANG Chenglong, YU Liran, YU Zicong, WANG Jing. Synergistic Effect of P5/HCl on the Performance Regulation of FDSSC Photoanode Sintered at Low Temperature[J]. Journal of Synthetic Crystals, 2025, 54(11): 2002-2014.

Figures/Tables 25

Fig.1 Basic structure of FDSSC

Fig.2 Chemical composition and physical characteristics of the key materials used in the experiment

Fig.3 Preparation process of TiO2 thin film

Fig.4 Bending test diagram of TiO2 thin film

Table 1 TiO2 film bending setting parameters

Length of the film/cm	Expansion amount/cm	R/mm
10	2	250
10	3.5	175
10	5	100

Fig.5 XRD patterns of TiO2 slurry with different proportions

Fig.6 SEM image and binary image of TiO2 thin film

Table 2 Average crack width of TiO2 thin films with different proportions

Sample	Pristine	5:1	4:1	3:1
Crack width/μm	3.242	2.935	2.589	3.086

Fig.7 Interparticle bonding mechanism in TiO2 film

Fig.8 Characterization of the microstructure of TiO2 particles based on 4:1 ratio

Fig.9 J-V curves of P5/HCl-P25-P100 TiO2 photoanode FDSSC with different ratios

Table 3 FDSSC photoelectric conversion parameters

Sample	V_oc/V	J_sc/（mA·cm^-2）	FF	PCE/%
Pristine	0.833	9.715	0.305	2.47
5:1	0.749	12.640	0.355	3.36
4:1	0.785	15.923	0.413	5.17
3:1	0.763	8.660	0.280	1.85

Fig.10 Based on the FDSSC photoelectric conversion model of P5/HCl-P25-P100 TiO2 photoanode

Fig.11 Electrochemical impedance spectroscopy of FDSSC device

Fig.12 Nyquist plots （a） and Bode plots （b） of FDSSC based on P5/HCl-P25-P100 TiO2 photoanode

Table 4 Electrochemical impedance spectroscopy parameters of photoanode FDSSC with different proportions

Sample	R_ct2/Ω	τ_n/ms
Pristine	13.25	43.6
5:1	8.65	46.4
4:1	6.97	51.7
3:1	17.49	42.4

Fig.13 SEM and binary images of TiO2 thin films with different bending radius

Table 5 Influence parameters of TiO2 thin film crack under different bending radius

Sample	m_0.5/μm	u/μm	∣u-m_0.5∣/μm	Crack percentage/%
Pristine	3.143	4.01	0.867	1.22
R=250 mm	3.514	4.67	1.156	2.21
R=175 mm	4.006	5.22	1.214	3.01
R=100 mm	4.969	5.37	0.401	3.68

Fig.14 Crack quantitative trend diagram under different bending radius

Fig.15 Frequency distribution of crack width of TiO2 thin films with different bending radius

Table 6 Parameters of crack width frequency distribution curve of TiO2 thin film under different bending radius

Sample	u_g/μm	u_g error/μm	u/μm	∣u-u_g∣/μm	W₅₀/μm	R²
Pristine	2.346 59	0.151 81	4.01	1.663 41	2.55	0.992 1
R=250 mm	3.213 57	0.530 27	4.67	1.456 43	3.15	0.945 88
R=175 mm	2.746 7	0.920 51	5.22	2.473 3	5.22	0.926 73
R=100 mm	3.757 41	0.119 63	5.37	1.612 59	5.37	0.911 53

Fig.16 J-V performance analysis of FDSSC under different bending conditions

Table 7 Photoelectric conversion parameters of FDSSC after bending

Sample	V_oc/V	J_sc/（mA·cm^-2）	FF	PCE/%
Pristine	0.785	15.923	0.413	5.17
R=250 mm	0.741	14.57	0.352	3.80
R=175 mm	0.714	10.94	0.352	2.76
R=100 mm	0.671	10.101	0.345	2.34

Fig.17 Nyquist diagram （a） and Bode diagram （b） of FDSSC under different bending conditions

Table 8 Electrochemical impedance spectroscopy parameters of FDSSC under different bending conditions

Sample	R_ct2/Ω	τ_n/ms
Pristine	6.97	51.7
R=250 mm	8.03	42.4
R=175 mm	9.59	41.6
R=100 mm	17.83	39.8

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