Advances in Perovskite Solar Cells

Abstract

widely commercialized, but possiblities to increase their performance are limited, because nowadays the so-called balance of systems (BoS) cost of PV modules makes up most of the cost. [ 1 ] As much of the BoS scales with area, performance improvement seems the only way to decrease the cost of PV power further. Therefore, new PV cells are sought either to allow for higher effi ciencies than what is possible with Si PV without cost increase, or, as explained in section 3.4, to provide lowcost added effi ciency to Si PV. Emerging solar cells such as dye-sensitized, bulkheterojunction and quantum-dot solar cells can be fabricated via low-temperature solution processing, that holds promise for low-cost large scale application, but best power conversion effi ciencies (PCE) are half of, or less than that of the best commercial Si PV cells. [ 2 ] This is where perovskite solar cells enter, as for the fi rst time in PV history it is possible to produce high-effi ciency cells at low monetary and energy costs, with apparent ease of fabrication from earth-abundant, readily available raw materials. The PCE for perovskite solar cells has increased from 2.2% to 20.1% since 2006, showing an inviting vista of commercialization. [ 3,4 ] Perovskite solar cells are named after the crystal structure of the light absorbers, the structure of the mineral CaTiO 3 . Many compounds with ABX 3 stoichiometry take this structure, where A and B are 12-and 8-coordinates cations, respectively, and X is the anion. [ 4 ] Of the many ABX 3 only few are suitable to be efficient light absorbers for solar cells due to requirements such as appropriate bandgap for good light-harvesting ability, energy level/band alignment with contacting materials, long charge carrier lifetime, τ, and high mobility, µ. Perovskites generally have divalent anions, and the strong electrostatic bonding mostly makes their (high) bandgaps not suitable for solar PV. Mitzi et al. initiated using perovskites containing halides, ammonium cations and Sn 2+ in optoelectronic devices, which formed the basis for the development of perovskites for solar cells. [ 5 ] Here we will focus on such halide perovskites, together with one divalent (Pb 2+ ) and one monovalent (mostly CH 3 NH 3 + ) cation. The most effi cient halide perovskite solar absorbers consist of organic ammonium ions (CH 3 NH 3 + or NH = CHNH 3 + ), Pb 2+ and halide ions (I − , Br − ).[ 4 ] CH 3 NH 3 PbI 3 possesses broad and intense light absorption. It is an ambipolar semiconductor (can be n-or p-type), and its charge carriers can have long diffusion lengths and lifetimes, which allow excellent PCE for solar cells made with it. [3][4][5][6] Another advantage of perovskite absorbers is the low-temperature solution-processing ability, which helps

New insight into solvent engineering technology from evolution of intermediates via one-step spin-coating approach

“…The power conversion efficiency (PCE) of perovskite device has undergone a rapid development from 3.8% to 22.1% since the first attempt to introduce organic-inorganic hybrid perovskite materials as the light absorber [1][2][3][4][5][6][7][8][9][10]. Such rapid increase in performance can be ascribed to its excellent properties, such as, ambipolar charge transport, high carrier mobility, long carrier diffusion, and large absorption coefficient [11,12].…”

Growth patterns and properties of aerosol-assisted chemical vapor deposition of CH3NH3PbI3 films in a single step

“…With a common formula CH3NH3MX3 (M = Pb or Sn; X = Cl, Br or I), the absorber layer is sandwiched between different electron and hole transport layers. Attempts to deposit high-quality optoelectronic PVK layers by one or two-step solution processes such as spin coating are widely spread [3,4], although challenging to scale up.…”

Reversible air-induced optical and electrical modulation of methylammonium lead bromide (MAPbBr3) single crystals

“…It is found that the PL intensity is much stronger in air than in vacuum, which is consistent with the previous works. 41,44,52 On the other hand, the resistance of perovskite single crystals, however, decreases when the environment is changed from air to vacuum. Both the optical and electrical changes are reversible without signs of material degradation.…”