Preparation And Photovoltaic Performance Of Solid-state Pb/S/EDT Quantum Dot Thin Film Sensitized TiO₂ Nanorod Array Solar Cells

Quantum dot sensitized solar cells(QDSCs)have a broad development prospects as a promising third-generation photovoltaic devices,which are recognized as a new type of solar cells with higher theoretic photoelectric conversion efficiency(PCE)and low cost of fabrication,have attracted tremendous attention as a potential solar cells nowadays.In this thesis,the preparation of solid-state Pb/S/EDT quantum-dot thin film sensitized TiO2 nanorod array solar cells and the corresponding photovoltaic performance were investigated.The Pb(NO3)2,Na2S and EDT were spin-coated step by step to prepared solid-state Pb/S/EDT quantum-dot thin film by spin-coating-assisted successive ionic layer absorption and reaction(SILAR),and the influence of TiO2 nanorod array microstructure,Pb(NO3)2 and Na2S concentration and Pb(NO3)2 and Na2S concentration ratios on the composition,microstructure,grain size,optical absorption of the Pb/S/EDT quantum-dot thin film sensitized TiO2 nanorod array and the corresponding solar cells photovoltaic performance were systemically investigated.The results reveal that when the hydrothermal temperature was 160?,the hydrothermal time were 90 min,100 min and 108 min,TiO2 nanorod arrays have the length,diameter and areal density of 460 um,40 um,340 ?m-2;630 nm,44 nm,330 ?m-2;720 nm,50 um,320?m-2?With the increase of hydrothermal time,the length and diameter of TiO2 nanorod arrays increased,and the areal density decreased.The 5 mmol·dm-3 Pb(NO3)2,5 mmol-dm-3 Na2S and 1%EDT(VEDT/VC2H5OH=1/99)were spin-coated step by step on the TiO2 nanorod arrays to prepared solid-state Pb/S/EDT quantum-dot thin film sensitized TiO2 nanorod arrays,and the PCE of corresponding solar cells were 2.17%,2.96%and 2.74%?Keeping the concentration of Pb(NO3)2 was 5 mmol dm-3,the concentration of Na2S were 5 mmol dm-3,3.5 mmol dm-3 and 2 mmol dm-3(Pb(NO3)2 and Na2S concentration molar ratios were 1:1,1:0.7,1:0.4),with the concentration of Na2S decreased from 5 mmol·dm-3 to 3.5 mmol dm-3 and 2 mmol·dm-3,the grain sizes of Pb/S/EDT quantum-dot thin film decreased from 7.9 nm to 7.1 nm and 6.5 nm,the absorption band-edges blue shift from 625 nm to 587 nm and 571 nm,the PCE of corresponding solar cells increased from 2.68%to 3.41%and 4.51%,the solar cells based on Pb(NO3)2 and Na2S concentration molar ratio was 1:0.4 showed the best PCE.Keeping the Pb(NO3)2 and Na2S concentration molar ratio was 1:0.4,when Pb(NO3)2 and Na2S concentration decreased from 7 mmol dm-3 and 2.8 mmol·dm-3 to 5 mmoldm-3,2 mmol dm-3 and 3 mmol·dm-3,1.2 mmol dm-3,the grain sizes of Pb/S/EDT quantum-dot thin film decreased from 7.5 um to 6.7 nm and 6.3 nm,the absorption band-edges blue shift from 580 nm to 558 nm and 535 nm,the PCE of corresponding solar cells were 3.37%,4.39%and 3.46%,the solar cells based on Pb(NO3)2 and Na2S concentration were 5 mmol dm-3 and 2 mmol·dm-3 showed the best PCE.