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Planar perovskite solar cells using organic charge selective contacts were fabricated. In a vacuum deposited perovskite-based solar cell, dopant and additive free triazatruxene as the hole transport layer was introduced for device fabrication. High open-circuit voltage of 1090 mV was obtained using methylammonium lead iodide ( E g =1.55 eV) as light harvesting material, thus representing a loss of only 460 mV which is in close vicinity of mature silicon technology (400 mV). The devices showed a very competitive photovoltaic performance, monochromatic incident photon-to-electron conversion efficiency of 80% and the power conversion efficiencies in excess of 15% were measured with a negligible degree of hysteresis. [ABSTRACT FROM AUTHOR]

The pressure to move towards renewable energy has inspired researchers to look for ideas in photovoltaics that may lead to a major breakthrough. Recently the use of perovskites as a light harvester has lead to stunning progress. The power conversion efficiency of perovskite solar cells is now approaching parity (>22 %) with that of the established technology which took decades to reach this level of performance. The use of a hole transport material (HTM) remains indispensable in perovskite solar cells. Perovskites can conduct holes, but they are present at low levels, and for efficient charge extraction a HTM layer is a prerequisite. Herein we provide an overview of the diverse types of HTM available, from organic to inorganic, in the hope of encouraging further research and the optimization of these materials. [ABSTRACT FROM AUTHOR]

In Anbetracht des riesigen Bedarfs an erneuerbaren Energien sind in den letzten Jahren die Forschungen in der Photovoltaik intensiviert worden. Ein großer Durchbruch war die Entdeckung, dass Perowskite als Lichtsammler eingesetzt werden können. Der Wirkungsgrad von Perowskit ‐ Solarzellen liegt bereits in der Größenordnung etablierter Photovoltaiktechnologien (>22%), die über Jahrzehnte erforscht und optimiert wurden. Eine bislang unverzichtbare Komponente von Perowskit ‐ Solarzellen ist das Lochtransportmaterial (HTM). Perowskite leiten selbst ebenfalls Elektronenlöcher, da diese aber nur in geringen Mengen vorhanden sind, muss eine HTM ‐ Schicht verwendet werden, um eine effiziente Ladungsextraktion zu gewährleisten. Wir bieten hier einen Überblick über die verschiedenen Arten von organischen und anorganischen HTMs und hoffen damit, die weitere Erforschung und Optimierung dieser Materialien zu unterstützen. Auf der Suche nach dem richtigen Material: Halbleitende Lochtransportmaterialien (HTMs) sind eine unverzichtbare Komponente in Perowskit ‐ Solarzellen. Die drei verfügbaren Klassen von Materialien – anorganische, polymere und molekulare HTMs – werden hier zusammengefasst, mit besonderem Schwerpunkt auf den optoelektrischen Eigenschaften molekularer HTMs als dem wirksamsten und aussichtsreichsten Materialtyp. [ABSTRACT FROM AUTHOR]

In recent years, organo-halide perovskite solar cells have garnered a surge of interest due to their high performance and low-cost fabrication processing. Owing to the multilayer architecture of perovskite solar cells, interface not only has a pivotal role to play in performance, but also influences long-term stability. Here we have employed diverse morphologies of electron selective layer (ESL) to elucidate charge extraction behavior in perovskite solar cells. The TiO2 mesoporous structure (three-dimensional) having varied thickness, and nanocolumns (1-dimensional) with tunable length were employed. We found that a TiO2 electron selective layer with thickness of about c.a. 100 nm, irrespective of its microstructure, was optimal for efficient charge extraction. Furthermore, by employing impedance spectroscopy at different excitation wavelengths, we studied the nature of recombination and its dependence on the charge generation profile, and results showed that, irrespective of the wavelength region, the fresh devices do not possess any preferential recombination site, and recombination process is governed by the bulk of the perovskite layer. Moreover, depending on the type of ESL, a different recombination mechanism was observed that influences the final behavior of the devices. [ABSTRACT FROM AUTHOR]