Organic-inorganic (hybrid) lead halide perovskites are taking the lead among the emerging photovoltaics technologies, thanks to the demonstration of power conversion efficiencies exceeding 20 %. Hybrid perovskites have a wide spectrum of desirable properties; they are direct bandgap semiconductors with very high absorption coefficients, high and balanced hole and electron mobility, and large diffusion length. A unique feature of these materials is their versatility in terms of bandgap energy, which can be tuned by simple exchange of their components. In this paper we present vacuum and hybrid deposition routes for the preparation of different organic-inorganic lead perovskite thin films, and their incorporation into efficient solar cells. The influence of the type of organic semiconductors used as hole/electron transport layer in p-i-n solar cells will be presented. We also discuss their electroluminescence properties, either for applications in light-emitting diodes or as a diagnostic tool of the optical and electronic quality of perovskite thin films. Finally, the effect of additives and dopants in the perovskite absorber as well as in the charge selective layers will be described.
A novel class of bottom emission electroluminescent device is described in which a metal oxide is used as the electron
injecting contact. The preparation of such a device is simple, and consists of the deposition of a thin layer of a metal
oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light emitting
layer and subsequently the deposition of a high workfunction (air stable) metal anode. This architecture allows for a low
cost electroluminescent device as no rigorous encapsulation is required. Electroluminescence with a high brightness level
reaching 6500 cd/m<sup>2</sup> is observed at voltages as low as 8 V, demonstrating the potential of this new approach to OLED
devices. Unfortunately the device efficiency is rather low caused by the high current density flowing through the device.
We show that the device only operates after the insertion of an additional hole injection layer in between the light
emitting polymer and the metal anode. A simple model that explains the observed experimental results and provides
avenues for further optimization of these devices is described. It is based on the idea that the barrier for electron injection
is lowered by the formation of the space charge field over the metal oxide-light emitting polymer interface due to the
build up of holes in the light emitting polymer layer.