ABSTRACT
Recently, ZnCdS nanocrystals (NCs) have attracted intense attention because of their specific optical properties and electrical characteristics. In this paper, a green and facile solution method is reported for the preparation of ZnCdS nanocrystals using dimethylsulfoxide as small molecular ligands. The ZnCdS nanocrystals are used as an interface modification material in the photovoltaic devices. It is found that the modification of ZnCdS on TiO2 surface not only suppresses the recombination loss of carriers but also reduces the series resistance of TiO2/active layer. Consequently, both of the short circuit current (Jsc) and the fill factor (FF) of the solar cells were significantly improved. Power conversion efficiency (PCE) of 7.75% based on TiO2/ZnCdS was achieved in contrast to 6.65% of the reference devices based on pure TiO2 film in organic solar cells. Furthermore, the PCE of perovskite solar cells based on TiO2/ZnCdS was observed with 8.3% enhancement compared to that of pure TiO2-based ones.
ABSTRACT
Organic-inorganic perovskite solar cells have recently emerged at the forefront of photovoltaics research. Here, for the first time, graphdiyne (GD), a novel two dimension carbon material, is doped into PCBM layer of perovskite solar cell with an inverted structure (ITO/PEDOT:PSS/CH3NH3PbI(3-x)Cl(x)/PCBM:GD/C60/Al) to improve the electron transport. The optimized PCE of 14.8% was achieved. Also, an average power conversion efficiency (PCE) of PCBM:GD-based devices was observed with 28.7% enhancement (13.9% vs 10.8%) compared to that of pure PCBM-based ones. According to scanning electron microscopy, conductive atomic force microscopy, space charge limited current, and photoluminescence quenching measurements, the enhanced current density and fill factor of PCBM:GD-based devices were ascribed to the better coverage on the perovskite layer, improved electrical conductivity, strong electron mobility, and efficient charge extraction. Small hysteresis and stable power output under working condition (14.4%) have also been demonstrated for PCBM:GD based devices. The enhanced device performances indicated the improvement of film conductivity and interfacial coverage based on GD doping which brought the high PCE of the devices and the data repeatability. In this work, GD demonstrates its great potential for applications in photovoltaic field owing to its networks with delocalized π-systems and unique conductivity advantage.
