Cu2AgInS2Se2 quantum dots sensitized porous TiO2 nanofibers as a photoanode for high-performance quantum dot sensitized solar cell

Cu2AgInS2Se2 alloyed quantum dots are synthesized through a simple hot injection method. Its tetragonal structure and crystallite size are determined by using X-ray diffraction analysis. Its optical properties are observed by using Ultraviolet-Vis absorption and PL emission spectroscopies. The oxidation state and elemental composition of Cu2AgInS2Se2 quantum dots are confirmed by X-ray photoelectron spectroscope analysis and energy dispersive X-ray analysis, respectively. The optical bandgap of the synthesized quantum dots is measured to be 1.29 eV. The synthesized Cu2AgInS2Se2 quantum dots are sensitized onto the porous TiO2 nanofibers (CAISSe/P-TiO2) and its morphological and optical properties are examined. The quantum dot sensitized solar cell is assembled using CAISSe/P-TiO2, polysulfide and Cu2S as the photoanode, electrolyte and the counter electrode exhibited photoconversion efficiency (PCE) of 5.87%, which is significantly higher than that assembled using Cu2AgInSe4 (4.21%) and Cu2AgInS4 (4.89%) quantum dots sensitized porous TiO2 NFs as the photoanodes.