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The ubiquitous hysteresis in the current-voltage characteristic of perovskite solar cells (PSCs) interferes in a proper determination of the diode ideality factor ( n ), a key parameter commonly adopted to analyze recombination mechanisms. An alternative way of determining n is by measuring the voltage variation of the ac resistances in conditions of negligible steady-state dc currents. A reliable analysis of n based on the determination of the resistive response, free of hysteretic influences, reveals two separated voltage exponential dependences using different perovskite absorbers (3D perovskites layer based on CH 3 NH 3 PbI 3 or mixed Cs 0.1 FA 0.74 MA 0.13 PbI 2.48 Br 0.39 ) and a variety of interlayers (2D perovskite thin capping). The dominant resistive element always exhibits an exponential dependence with factor n ≈ 2 , irrespective of the type of perovskite and capping layers. In addition, a non-negligible resistive mechanism occurs at low-frequencies (with voltage-independent time constant ~ 1 s) which is related to the kinetic properties of the outer interfaces, with varying ideality factor ( n = 2 for CH 3 NH 3 PbI 3 , and n = 1.5 for Cs 0.1 FA 0.74 MA 0.13 PbI 2.48 Br 0.39 ). Our work identifies common features in the carrier recombination mechanisms among different types of high-efficiency PSCs, and simultaneously signals particularities on specific architectures, mostly in the carrier dynamics at outer interfaces. [ABSTRACT FROM AUTHOR]

A simple carbazole-based conjugated enamine V950 was synthesized, fully characterized and incorporated into a perovskite solar cell, which displayed high power conversion efficiency close to 18%. The investigated hole transporting material was synthesized via an extremely simple route (one step, no expensive catalysts, no column chromatography or sublimation purification) from commercially available and relatively inexpensive starting reagents, resulting in more than one order of magnitude lower cost of the final product compared to the commercial 2,2′,7,7′-tetrakis( N , N -di- p -methoxy-phenylamine)-9-9′-spirobifluorene (spiro-OMeTAD). This material promises to be a viable p-type organic charge conductor to be employed in the scale-up and manufacturing of perovskite solar modules. [ABSTRACT FROM AUTHOR]

Amino donor groups-substituted zinc(II) phthalocyanines (ZnPcs) BI25 , BL07 and BL08 were obtained via cyclotetramerization of suitable phthalonitriles that were synthesized by Pd catalyzed amination reaction between 4-iodophthalonitrile and a selected secondary amine. The BI25 , BL07 and BL08 ZnPcs were characterized using spectroscopic and electrochemical methods, and used as hole transporting layer in perovskite solar cells. The open circuit voltage (V OC ) of perovskite solar cell devices reached close to 1 V, and the short-circuit current density (J SC ) values evaluated from J-V curves were 16.2, 8.42, and 16.9 mA/cm 2 , respectively, demonstrating influence of the HOMO levels of ZnPcs. A power conversion efficiency of 11.75% was obtained in the case of BI25 , which is the highest value ever reported using ZnPcs as HTMs in perovskite solar cells with traditional device geometry. [ABSTRACT FROM AUTHOR]