PACS: Efficiency and performance of solar cells, 88.40.hj; Organic-inorganic hybrid nanostructures, 81.07.Pr; Semiconductors thin films,
73.61.Jc; Reviews, 01.30.Rr.
Photovoltaic (PV) technologies has received an incremental attention during the last decades as one of the most feasible options for humankind future sustainable development. In fact, it has been recently suggested [1] that PVs will account for 35 % of the additional electricity generation capacity installed globally by 2040. Nowadays, the current largest contributor to Si module price now comes from cell encapsulation [
1]. Nevertheless, despite the manufacturing optimization, the fabrication process is still complex and expensive. Furthermore, it was only recently when a power conversion efficiency (PCE) of 26 % was achieved for Si cells
[
2] from a theoretical limit around 29 % [
3].
Aiming at the reduction of costs and enhance versatility, newer technologies have been developed such as typical CdTe and CIGS thin film solar cells [
4] or the so called emerging technologies, for instance, dye-sensitized solar cells (DSSCs) [
5] and organic solar cells [
6]. Nevertheless, possibly the most recent and promising PV devices are the denominated perovskite solar cells (PSCs), that in about four years have already achieved PCE larger than 22 % for laboratory cells [
2] with a theoretical limit evaluated at 31 % [
7]. These results match the current record for CdTe thin films solar cells, the second technology in the market and
the one with lower manufacturing costs, which make the PV community believe in a prompt overpassing by PSCs. This is also endorsed by several potential applications such as: building integration in windows with transparency and/or colors, flexibility and high efficiency in tandem configuration assembly silicon technology.
The perovskites is the denomination of a wide family of materials with the general formula ABX
3 and the crystal structure of the mineral perovskite, the calcium titanate (CaTiO
3). Figure
1 illustrate such structure where the A cation is coordinated with twelve X ions and the B cation with six. Thus, the A cation is normally found to be somewhat larger than the B cation [
8]. Several properties have been found for these materials for many years, e.g. ferroelectric, piezoelectric, ferromagnetic, antiferromagnetic, thermoelectric, insulating, semiconducting, conducting, superconducting and catalyst [
9]. However, it was not until 2006 when PV application was first reported by Miyasaka and co-workers for devices with methylammonium lead halide perovskites CH3NH3Pb(I3, Br3) as absorber material, proving less than 1 % of PCE for all solid-state cells [
10]. These first works and further optimizations by Park and co-workers
[
11] resulted in the “perovskite phenomena” trigger when in 2012 up to 10 % efficiency CH3NH3PbI3 [
12] and mixed halide CH3NH3PbI3-xClx [
13] based solid-state devices were