Revealing the origin of voltage loss in mixed-halide perovskite solar cells

Mahesh, Suhas; Ball, James M.; Oliver, Robert D. J.; McMeekin, David P.; Nayak, Pabitra K.; Johnston, Michael B.; Snaith, Henry J.

doi:10.1039/c9ee02162k

Cited by 345 publications

(399 citation statements)

References 48 publications

Supporting

Mentioning

359

Contrasting

Unclassified

Order By: Relevance

“…Notably, in these devices the V OC loss appears to be important and recent experimental works associated it not only to phase/chemical instability. [ 44,45 ] Similar observations can be made for fully inorganic systems. Thus, further experimental and theoretical investigations, where the role of cations and halides of different nature is accounted, are needed.…”

Section: Resultssupporting

confidence: 63%

Defect Tolerance and Intolerance in Metal‐Halide Perovskites

Kim

Petrozza

2020

Advanced Energy Materials

126

View full text Add to dashboard Cite

Defect tolerance has been often invoked during the past years to explain the surprising optimal device performance despite the fact we are dealing with a material which can self-assemble at low temperature and is mainly based on ionic bonds. We believe there is not a unique explanation for such observation. One way to understand this phenomenon is understanding the nature of carriers and how they are transported across thin films. So far, there is a general consensus on the nature of photo-carriers, defined as large polarons in 3D perovskites. [9] There have been reports suggesting that such large polarons would be able to screen the carrier-carrier and carrier-defect scattering, thus contributing to the long lifetime of the carriers. [10] Nevertheless, the carrier transport mechanism has not been elucidated yet and the debate on the role of a soft lattice, low energy phonons, and electron-phonon interaction on the screening from defects is still lively. The other side of the medal is looking at the nature of defects and how they will influence the carriers dynamics. We are aware that in perovskite thin films the formation of defects may be strongly influenced by the preparation of perovskite precursors, their processing, crystallization, post treatment procedures and even device operation. Theoretical studies can help to take the right path and understand the intrinsic properties/behaviors of defects. For a first screening on the role of defects on the primary optoelectronic properties of a semiconductor, one has to gather information regarding the probability of forming such defects, the thermodynamic ionization levels of the electronic states they form, and how probable the capture of carriers occurs through an evaluation of the capture cross-section. Density functional theory (DFT) calculations indicate that point defects with the lowest formation energy, mainly vacancies, generally introduce shallow trap states (Figure 1a). For many semiconductors the CB and VB have an antibonding and bonding character. Such a property can bring about deep defect states in the bandgap when an atom is removed. [11] However, in metal-halide perovskites CB and VB both exhibit antibonding character. In MAPbI 3 (MA = CH 3 NH 3 +), VB and CB edges are generated from the interaction between Pb 6s and I 5p orbitals, and Pb 6p and I 5p orbitals, respectively. [12,13] Strong antibonding coupling between Pb 6s orbital and I 5p orbital expands VB bandwidth and raises VB edge, suggesting that most defect states are located within or closer to VB edge. On the other Metal-halide perovskites present exceptional optoelectronic properties such as large light absorption coefficients, long free charge carrier diffusion lengths with ambipolar character. They are apparently protected by what is often described as a "defect tolerance" which has allowed to achieve, relatively quickly, highly performing devices. Nevertheless, there also exists a "defect intolerance" when it is dealt with stability. Further rationalization of the passivation strategi...

show abstract

Section: Resultssupporting

confidence: 63%

Defect Tolerance and Intolerance in Metal‐Halide Perovskites

Kim

Petrozza

2020

Advanced Energy Materials

126

View full text Add to dashboard Cite

show abstract

“…[52] Thus, quantifying the V OC deficit has become a popular way to quantify the nonradiative recom bination losses of a complete PSC. [53] In the case of 100% radia tive recombination, the radiative limit of V OC is V OC,rad , which can be expressed as [10,54,55]…”

Section: Figure 5amentioning

confidence: 99%

Suppressing Defects‐Induced Nonradiative Recombination for Efficient Perovskite Solar Cells through Green Antisolvent Engineering

et al. 2020

View full text Add to dashboard Cite

Organic–inorganic hybrid perovskites have attracted considerable attention due to their superior optoelectronic properties. Traditional one‐step solution‐processed perovskites often suffer from defects‐induced nonradiative recombination, which significantly hinders the improvement of device performance. Herein, treatment with green antisolvents for achieving high‐quality perovskite films is reported. Compared to defects‐filled ones, perovskite films by antisolvent treatment using methylamine bromide (MABr) in ethanol (MABr‐Eth) not only enhances the resultant perovskite crystallinity with large grain size, but also passivates the surface defects. In this case, the engineering of MABr‐Eth‐treated perovskites suppressing defects‐induced nonradiative recombination in perovskite solar cells (PSCs) is demonstrated. As a result, the fabricated inverted planar heterojunction device of ITO/PTAA/Cs0.15FA0.85PbI3/PC61BM/Phen‐NADPO/Ag exhibits the best power conversion efficiency of 21.53%. Furthermore, the corresponding PSCs possess a better storage and light‐soaking stability.

show abstract

“…4 It could also reach higher PCEs if combined with other solar cell technologies to make tandem devices. 5 Since the pioneering work with an efficiency of 3.8%, PSCs have witnessed an ever-growing increase in efficiency. They have now achieved a lab-scale certified PCE of 25.2% rivaling the performance of commercial photovoltaic devices such as crystalline silicon or cadmium telluride (CdTe) solar cells.…”

Section: Introductionmentioning

confidence: 99%