DIKUL - logo
E-viri
Celotno besedilo
Recenzirano
  • High Efficiency and High Op...
    Cohen, Bat‐El; Wierzbowska, Małgorzata; Etgar, Lioz

    Advanced functional materials, 02/2017, Letnik: 27, Številka: 5
    Journal Article

    An important property of hybrid layered perovskite is the possibility to reduce its dimensionality to provide wider band gap and better stability. In this work, 2D perovskite of the structure (PEA)2(MA)n–1PbnBr3n+1 has been sensitized, where PEA is phenyl ethyl‐ammonium, MA is methyl‐ammonium, and using only bromide as the halide. The number of the perovskite layers has been varied (n) from n = 1 through n = ∞. Optical and physical characterization verify the layered structure and the increase in the band gap. The photovoltaic performance shows higher open circuit voltage (Voc) for the quasi 2D perovskite (i.e., n = 40, 50, 60) compared to the 3D perovskite. Voc of 1.3 V without hole transport material (HTM) and Voc of 1.46 V using HTM have been demonstrated, with corresponding efficiency of 6.3% and 8.5%, among the highest reported. The lower mobility and transport in the quasi 2D perovskites have been proved effective to gain high Voc with high efficiency, further supported by ab initio calculations and charge extraction measurements. Bromide is the only halide used in these quasi 2D perovskites, as mixing halides have recently revealed instability of the perovskite structure. These quasi 2D materials are promising candidates for use in optoelectronic applications that simultaneously require high voltage and high efficiency. A quasi 2D perovskite materials based on bromide, having low exciton binding energy, high absorbance coefficient, and high stability is presented. These materials provide high open circuit voltage and high power conversion efficiency in perovskite solar cells with and without hole transport material.