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Photovoltaics are regarded as the promising solution to resolve energy and environmental problems owing to their high power conversion efficiency and zero emissions. However, the narrow-spectra absorption range and serious recombination reactions at electrode/electrolyte interfaces are two major drawbacks for high-performance solar cells. Herein, a new way of synthesizing organic-inorganic hybrid CH 3 NH 3 PbX 3 (X = Cl, Br or I) perovskite quantum dots (PQDs) is demonstrated by dropping perovskite precursor solution into anhydrous toluene. After a systematic study, the results demonstrate that the energy levels of PQDs can be tuned through optimizing the stoichiometric ratio of halide ions, showing good optical properties for photovoltaic applications. A quasi-solid-state sensitized solar cell with configuration of FTO/ m -TiO 2 /PQDs/dye/long persistence phosphor/gel electrolyte/Pt/FTO is fabricated, yielding an impressive power conversion efficiency as high as 7.91%, which is higher than 7.26% for referenced device free of PQDs. The improved performances are mainly attributed to the increased light absorption as well as reduced recombination upon the incorporation of PQDs and long persistence phosphor into devices. [ABSTRACT FROM AUTHOR]

Development of high-performance light harvesters is a persistent goal for mesoscopic solar cells. In the current work, lead-free CH 3 NH 3 SnBr 3-x I x (x = 0–3) perovskite quantum dots (QDs) are made by integrating Br − ions into host crystal structure. Through tuning Br/I ratio, these perovskite-structured QDs are highlighted with tunable optical bandgaps. When applied as light harvesters for mesoscopic solar cell applications, the devices yield reasonable power conversion efficiency and rapid start-up behaviors. An efficiency of 8.79% is achieved for CH 3 NH 3 SnBr 3-x I x QDs and N719 co-sensitized mesoscopic solar cells. [ABSTRACT FROM AUTHOR]