Comparative Study on Planar-silicon and Nano-silicon Si/PCBM Inorganic-organic Hybrid Junctions

doi:10.15541/jim20140411

Abstract

Abstract:

Inorganic-organic heterojunction devices based on organic polymer and inorganic semiconductors has attracted extensive attention for high performance hybrid solar cell applications, due to the combined advantage of high carrier mobility of inorganic semiconductors and easy processing, strong absorption of organic polymers. In this study, both planar-Si and nano-Si were combined with spin-coated [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) organic film to form Si/PCBM inorganic/organic hybrid junctions. A comparative study was performed through quantitative electrical analysis of planar-Si/PCBM and nano-Si/PCBM, respectively. In general, both devices exhibited a rectifying diode-like behavior. However, a higher turn-on voltage and smaller current density were observed from nano-Si/ PCBM junctions, which was in contradiction with the expectation from the view of junction area. The corresponding mechanisms were further investigated with measurements of impedance spectroscopy (IS). Our results indicated that this abnormal electrical characteristic of nano-Si/PCBM compared with normal p-n junction was highly associated with the parasitic effects caused by the defect states at the junction interface.

Key words: inorganic-organic heterojunction, nano-Si/PCBM, impedance spectroscopy

CLC Number:

TB34

LIU Wei-Feng, BIAN Ji-Ming, LUO Ying-Lin, QIAO Jian-Kun, ZHAO Chun-Yi. Comparative Study on Planar-silicon and Nano-silicon Si/PCBM Inorganic-organic Hybrid Junctions[J]. Journal of Inorganic Materials, 2015, 30(2): 214-218.

Figures/Tables 4

Fig. 1 Three-dimensional schematic diagrams of planar-Si/PCBM and nano-Si/PCBM inorganic/organic, the middle is cross-sectional SEM images of planar-Si and nano-Si

Fig. 2 I-V curves of the planar-Si/PCBM and nano-Si/PCBM inorganic/organic heterojunctions

Fig. 3 The cole-cole plots of planar-Si/PCBM heterojunction(a) and nano-Si/PCBM heterojunction with the equivalent electrical circuit (inset), (b) and their CPE-P values (CPE-P1 and CPE-P2, respectively) against the ideal value (c)

Table 1 Summary of the circuit parameters obtained from the software of Z-view

Bias/V	planar-Si/PCBM heterojuntion				nano-Si/PCBM heterojuntion
Bias/V	R_p1/MΩ	CPE-T₁/F		CPE-P₁	R_p2/MΩ	CPE-T₂/F	CPE-P₂
0	0.425000	3.87×10^-8	0.89571		3.390000	3.52×10^-8	0.89312
0.1	0.056518	4.22×10^-8	0.97869		0.646970	4.12×10^-8	0.87240
0.2	0.023646	3.61×10^-8	0.80414		0.132260	5.96×10^-8	0.83301
0.3	0.007371	2.34×10^-8	0.85180		0.043541	6.47×10^-8	0.87478
0.4	0.001279	1.86×10^-8	0.87707		0.030387	3.41×10^-8	0.53783
0.5	0.000820	1.39×10^-8	0.92249		0.014757	2.92×10^-8	0.54729

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