Effects of SnS Doping on Photovoltaic Performance of P3HT:PCBM Multilayer Heterojunction Solar Cells

doi:10.15541/jim20150342

Abstract

Abstract:

SnS was deposited on the surface of FTO/TiO₂ electrodes with different molar concentration ratio of Sn²⁺ and S^2- using successive ionic layer absorption and reaction (SILAR) method. Afterwards, the as-prepared TiO₂/SnS composite electrode was assembled into a multilayer heterojunction solar cell with an architecture of FTO/TiO₂/SnS/ P3HT:PCBM/Ag. The TiO₂/SnS composite films were characterized by scanning electron microscopy (SEM), Raman spectra analysis and Glow discharge optical emission spectrometer (GD-OES). The photovoltaic performance of solar cells were determined using UV-Vis spectra and I-V curves. Results showed that incorporation of SnS significantly improved the short-circuit current of the multilayer heterojunction solar cells. Meanwhile, the dependence of the photovoltaic performance of solar cells on the molar concentration ratio of Sn²⁺/S^2- was investigated systematically. During the SILAR processes, a series of electrodes were prepared in the precusor solutions with different Sn²⁺/S^2- molar concentration ratios (n(Sn²⁺):n(S^2-)= 1:1, 1:1.25, 1:1.5, 1:1.75 and 1:2). Moreover, GD-OES method distinguished the effects of Sn²⁺/S^2- ratio on the SnS_x layer deposition. It was found that the Sn²⁺/S^2- ratio of SILAR precursors, dominated by thickness and chemical composition of SnS_x, affected photovoltaic performance of the solar cells significantly. I-V test results testified that the ratio of Sn²⁺/S^2- molar concentration was optimized at 1:1.5, which resulted in the highest photoelectric conversion efficiency. The open-circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF), and power conversion efficiency (PCE) reached 0.373 V, 1.92 mA/cm², 51.2%, and 0.369%, respectively.

Key words: solar cells, SILAR, SnS, multilayer heterojunction

CLC Number:

TQ174

LU Guan-Hong, ZHAO Xin-Luo, WANG Yan, ZHU Shu-Ying, SUN Jing, XIE Xiao-Feng. Effects of SnS Doping on Photovoltaic Performance of P3HT:PCBM Multilayer Heterojunction Solar Cells[J]. Journal of Inorganic Materials, 2016, 31(3): 263-268.

Figures/Tables 7

Fig. 1 Structure and energy-level alignment of the multilayer heterojunction solar cell

Fig. 2 SEM images of TiO2/SnS/P3HT:PCBM multilayer electrodes(a) Surface of TiO2 electrode; (b) Side view of TiO2 electrode; (c) Surface of TiO2/SnS composite electrode; (d) Side view of TiO2/SnS composite electrode; (e) Surface of TiO2/SnS/P3HT:PCBM composite electrode; (f) Side view of the multilayer heterojunction solar cell

Fig. 3 UV-Vis adsorption spectra of as-prepared TiO2/SnS films deposited in precusor solutions with different Sn2+/S2- concentration ratios

Fig. 4 I-V curves of the multilayer solar cells deposited in precusor solutions with different Sn2+/S2- concentration ratios

Table1 Photovoltaic parameters including Voc, Jsc, FF and PCE of the multilayer heterojunction solar cells (S0~S5)

Sample	V_oc/V	J_sc/(mA·cm^-2)	FF/%	PCE/%
S0	0.440	0.81	41.5	0.148
S1	0.286	1.03	47.0	0.139
S2	0.296	1.15	51.9	0.177
S3	0.373	1.92	51.2	0.369
S4	0.269	1.00	48.1	0.129
S5	0.264	1.09	45.7	0.132

Fig. 5 Raman spectra of as-prepared TiO2/SnS deposited in precusor solutions with different Sn2+/S2- concentration ratios

Fig. 6 Sn and S elements distribution curves of solar cells (a) S elements distribution curve; (b) Sn elements distribution curve (Ⅰ/Ⅱ/Ⅲ/Ⅳ corresponding to Ag, TiO2/SnS/P3HT:PCBM, FTO, Glass)

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