Defect density and dielectric constant in perovskite solar cells

Abstract

We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH 3 NH 3 PbI x Cl 1Àx perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66 eV below the conduction band and one at 0.24 eV below the conduction band. The attempt to escape frequency is in the range of 2 Â 10 11 /s. Quantum efficiency data indicate a bandgap of 1.58 eV.

Under the spotlight: The organic–inorganic hybrid halide perovskite for optoelectronic applications

“…3.4. Such shallow defects do not serve as nonradiative recombination sites as do deep defects with energy levels near mid-bandgap, as have been experimental observed [156,157]. However, simulation results also predict that films grown under iodine-rich conditions are prone to a high density of deep electronic traps (recombination centers) [158].…”

Highly c-axis oriented AlN film grown by unbalanced magnetron reactive sputtering and its electrical properties

“…When the applied electric-field frequency is lower than the relaxation frequency, these defects can keep up with the change of the applied electric field, so they have substantial contribution to the dielectric constant. In contrast, with the increase of electric-field frequency, this part of contribution by the relaxation polarization decreases rapidly that results in the sharp decline of the dielectric constant [37,38], as shown in Fig. 6 (a).…”

Device engineering of perovskite solar cells to achieve near ideal efficiency

“…Our theoretical analysis and numerical simulations identify (a) the detailed balance performance limits (b) the physical mechanisms that contribute to sub-optimal performance of current perovskite based solar cells, and (c) suggest novel schemes to further improve the performance. Indeed, our simulations show that it is 15 possible to achieve > 25% efficiency with near ideal FF for an optimally designed perovskite based solar cell -a result that could be of immense interest to the community.…”

“…While a comprehensive literature survey is beyond the scope of this manuscript, we would like to mention that there has been reports of high efficiency solar cells with combination of perovskite materials 2 , better reproducibility 7 and stability 8 , usage of flexible substrate 9 , organic materials as both electron and hole transport layers 10 , large grain size perovskite fabrication 11 , perovskite based tandem cell 12,13 , etc.. There has also been efforts towards better understanding of material properties [14][15][16] , including the recombination strengths 4,[17][18][19] and mobility. 4,19,20 Despite the above mentioned exciting achievements in experimental research on perovskite solar cells, the corresponding theoretical understanding is lacking in many aspects.…”