200-nm long TiO_2 nanorod arrays for efficient solid-state Pb S quantum dot-sensitized solar cellsR

To ensure the infiltration of spiro-OMeTAD into the quantum dot-sensitized photoanode and to consider the limit of the hole diffusion length in the spiro-OMeTAD layer, a rutile TiO2 nanorod array with a length of 200 nm, a diameter of 20 nm and an areal density of 720 ram 2 was successfully prepared using a hydrothermal method with an aqueous-grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 ℃ for 75 min. PbS quantum dots were deposited by a spin coating-assisted successive ionic layer adsorption and reaction （spin-SILAR）, and all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells were fabricated using spiro-OMeTAD as electrolytes. The results revealed that the average crystal size of PbS quantum dots was -78 nm using Pb（NO3）2 as the lead source and remain unchanged with the increase of the number of spin-SILAR cycles. The all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells with spin-SILAR cycle numbers of 20, 30 and 40 achieved the photoelectric conversion efficiencies of 3.74%, 4.12% and 3.11%, respectively, under AM 1.5 G illumination （100 mW/cm2）.

The pyrolysis preparation of the compact and full-coverage AgSbS_(2) thin films and the photovoltaic performance of the corresponding solar cells

The preparation of the compact and full-coverage AgSbS;thin films is firstly reported using the pyrolysis of the Ag-butyldithiocarbamate and Sb-butyldithiocarbamate complex solution in DMF.The influence of the preparation temperature on the crystal phase,optical absorption,morphology of the AgSbS;thin films is systematically investigated.The AgSbS;thin films at 150°C for 30 min are composed of the individual nanoparticles with the particle sizes of 30–60 nm.When the AgSbS_(2)thin films are further heated at 350℃for 2 min,the individual AgSbS_(2)nanoparticles are melted together and the grain boundary between the AgSbS_(2)nanoparticles disappear.The solar cells with the architecture of FTO/compact TiO_(2)/AgSbS_(2)/spiro-OMe TAD/Au achieve the photoelectric conversion efficiency(PCE)of 2.09%,along with the open-circuit voltage of 0.44 V,the short-circuit photocurrent density of 10.49 m A cm^(-2),the fill factor of 0.45.The PCE of 2.09%is the highest value for the AgSbS_(2)solar cells.