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The optoelectronic role of chlorine in CH3NH3PbI3(Cl)-based perovskite solar cells.

Chen Q, Zhou H, Fang Y, Stieg AZ, Song TB, Wang HH, Xu X, Liu Y, Lu S, You J, Sun P, McKay J, Goorsky MS, Yang Y - Nat Commun (2015)

Bottom Line: Specifically, chlorine incorporation has been shown to affect the morphological development of perovksite films, which results in improved optoelectronic characteristics for high efficiency.Here we report an effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled.The chlorine incorporation is found to mainly improve the carrier transport across the heterojunction interfaces, rather than within the perovskite crystals.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA [2] California NanoSystems Institute, University of California, Los Angeles, California 90095, USA.

ABSTRACT
Perovskite photovoltaics offer a compelling combination of extremely low-cost, ease of processing and high device performance. The optoelectronic properties of the prototypical CH3NH3PbI3 can be further adjusted by introducing other extrinsic ions. Specifically, chlorine incorporation has been shown to affect the morphological development of perovksite films, which results in improved optoelectronic characteristics for high efficiency. However, it requires a deep understanding to the role of extrinsic halide, especially in the absence of unpredictable morphological influence during film growth. Here we report an effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled. The chlorine incorporation is found to mainly improve the carrier transport across the heterojunction interfaces, rather than within the perovskite crystals. Further optimization according this protocol leads to solar cells achieving power conversion efficiency of 17.91%.

No MeSH data available.


Related in: MedlinePlus

Perovskite film fabrication.Schematic illustration of different approaches to incorporate chlorine in the perovskite films. The Reference sample was obtained by a modified two-step solution process, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (for example, 1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. Sample 2 was obtained by a proper treatment on the Reference sample with CH3NH3Cl solution.
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f1: Perovskite film fabrication.Schematic illustration of different approaches to incorporate chlorine in the perovskite films. The Reference sample was obtained by a modified two-step solution process, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (for example, 1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. Sample 2 was obtained by a proper treatment on the Reference sample with CH3NH3Cl solution.

Mentions: Figure 1 schematically illustrates the rational approach to incorporating chlorine into the CH3NH3PbI3 film, where the CH3NH3Cl was intentionally involved either before or after the perovskite film formation (see Supplementary Methods). A CH3NH3PbI3 film without chlorine (Reference) was prepared by a modified two-step solution process4142, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. The as-formed CH3NH3PbI3 film possesses compact polycrystalline texture with full surface coverage and large grain size, features which are distinct from the poor film quality obtained from conventional one-step preparations. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. In contrast, the Reference sample was further treated with a CH3NH3Cl solution to obtain Sample 2, where chlorine was most likely incorporated at the surface or grain boundaries of the CH3NH3PbI3 film. Thus, extrinsic chlorine in both Samples 1 and 2 was rationally introduced into the perovskite films in a controllable manner without severe interference of film conformity. While the platform established here uses chlorine as an example, it can be generalized for further investigation of the effects of other extrinsic ions.


The optoelectronic role of chlorine in CH3NH3PbI3(Cl)-based perovskite solar cells.

Chen Q, Zhou H, Fang Y, Stieg AZ, Song TB, Wang HH, Xu X, Liu Y, Lu S, You J, Sun P, McKay J, Goorsky MS, Yang Y - Nat Commun (2015)

Perovskite film fabrication.Schematic illustration of different approaches to incorporate chlorine in the perovskite films. The Reference sample was obtained by a modified two-step solution process, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (for example, 1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. Sample 2 was obtained by a proper treatment on the Reference sample with CH3NH3Cl solution.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490385&req=5

f1: Perovskite film fabrication.Schematic illustration of different approaches to incorporate chlorine in the perovskite films. The Reference sample was obtained by a modified two-step solution process, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (for example, 1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. Sample 2 was obtained by a proper treatment on the Reference sample with CH3NH3Cl solution.
Mentions: Figure 1 schematically illustrates the rational approach to incorporating chlorine into the CH3NH3PbI3 film, where the CH3NH3Cl was intentionally involved either before or after the perovskite film formation (see Supplementary Methods). A CH3NH3PbI3 film without chlorine (Reference) was prepared by a modified two-step solution process4142, where PbI2 and CH3NH3I were sequentially deposited via spin-coating and subsequently annealed. The as-formed CH3NH3PbI3 film possesses compact polycrystalline texture with full surface coverage and large grain size, features which are distinct from the poor film quality obtained from conventional one-step preparations. Sample 1 was obtained via the same procedure, except that a solution of CH3NH3Cl and CH3NH3I (1:10 in weight) was used instead of CH3NH3I solution to introduce chlorine during the film growth. In contrast, the Reference sample was further treated with a CH3NH3Cl solution to obtain Sample 2, where chlorine was most likely incorporated at the surface or grain boundaries of the CH3NH3PbI3 film. Thus, extrinsic chlorine in both Samples 1 and 2 was rationally introduced into the perovskite films in a controllable manner without severe interference of film conformity. While the platform established here uses chlorine as an example, it can be generalized for further investigation of the effects of other extrinsic ions.

Bottom Line: Specifically, chlorine incorporation has been shown to affect the morphological development of perovksite films, which results in improved optoelectronic characteristics for high efficiency.Here we report an effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled.The chlorine incorporation is found to mainly improve the carrier transport across the heterojunction interfaces, rather than within the perovskite crystals.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA [2] California NanoSystems Institute, University of California, Los Angeles, California 90095, USA.

ABSTRACT
Perovskite photovoltaics offer a compelling combination of extremely low-cost, ease of processing and high device performance. The optoelectronic properties of the prototypical CH3NH3PbI3 can be further adjusted by introducing other extrinsic ions. Specifically, chlorine incorporation has been shown to affect the morphological development of perovksite films, which results in improved optoelectronic characteristics for high efficiency. However, it requires a deep understanding to the role of extrinsic halide, especially in the absence of unpredictable morphological influence during film growth. Here we report an effective strategy to investigate the role of the extrinsic ion in the context of optoelectronic properties, in which the morphological factors that closely correlate to device performance are mostly decoupled. The chlorine incorporation is found to mainly improve the carrier transport across the heterojunction interfaces, rather than within the perovskite crystals. Further optimization according this protocol leads to solar cells achieving power conversion efficiency of 17.91%.

No MeSH data available.


Related in: MedlinePlus