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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

Optimized device performance.Device performance of record solar cell based on Sample 1 with further optimization. The optimized fabrication condition for perovskite solar cell is carried out under the deposition of the mixed solution (CH3NH3Cl/CH3NH3I=1:10) on PbI2 film, followed by a 135 °C, 15 min baking.
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f4: Optimized device performance.Device performance of record solar cell based on Sample 1 with further optimization. The optimized fabrication condition for perovskite solar cell is carried out under the deposition of the mixed solution (CH3NH3Cl/CH3NH3I=1:10) on PbI2 film, followed by a 135 °C, 15 min baking.

Mentions: To fully explore the advantages of Cl incorporation on device performance, devices based on Sample 1 were subsequently optimized (Supplementary Figs 3 and 4). First, the annealing time and temperature have been carefully investigated when perovskite crystal growth occurs from in situ conversion of PbI2 framework. It is found that a relatively higher temperature of 135 °C for a period of 15 min produces the best device performance as a result of the compromise between the grain size and possible defects in the film. The concentration of incorporated chlorine has also been studied to assess its influence on device performance. Measured PCE is maximized when the weight ratio of CH3NH3Cl/CH3NH3I used was 1:10, and dropped significantly when the weight ratio was increased to 3:10. Given that the as-prepared film maintains good conformity and surface coverage (Supplementary Fig. 5), this indicates that a high concentration of CH3NH3Cl is detrimental to device performance, possibly due to increased trap states in the perovskite film or the relevant interfaces. Derived from Sample 1, the best device exhibits outstanding performance with a JSC of 21.45 mA cm−2, VOC of 1.077 V, FF of 77.57% and PCE of 17.91%, as shown in Fig. 4. Studies of device hysteresis and stability are provided in Supplementary Figs 6 and 7, respectively.


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)

Optimized device performance.Device performance of record solar cell based on Sample 1 with further optimization. The optimized fabrication condition for perovskite solar cell is carried out under the deposition of the mixed solution (CH3NH3Cl/CH3NH3I=1:10) on PbI2 film, followed by a 135 °C, 15 min baking.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Optimized device performance.Device performance of record solar cell based on Sample 1 with further optimization. The optimized fabrication condition for perovskite solar cell is carried out under the deposition of the mixed solution (CH3NH3Cl/CH3NH3I=1:10) on PbI2 film, followed by a 135 °C, 15 min baking.
Mentions: To fully explore the advantages of Cl incorporation on device performance, devices based on Sample 1 were subsequently optimized (Supplementary Figs 3 and 4). First, the annealing time and temperature have been carefully investigated when perovskite crystal growth occurs from in situ conversion of PbI2 framework. It is found that a relatively higher temperature of 135 °C for a period of 15 min produces the best device performance as a result of the compromise between the grain size and possible defects in the film. The concentration of incorporated chlorine has also been studied to assess its influence on device performance. Measured PCE is maximized when the weight ratio of CH3NH3Cl/CH3NH3I used was 1:10, and dropped significantly when the weight ratio was increased to 3:10. Given that the as-prepared film maintains good conformity and surface coverage (Supplementary Fig. 5), this indicates that a high concentration of CH3NH3Cl is detrimental to device performance, possibly due to increased trap states in the perovskite film or the relevant interfaces. Derived from Sample 1, the best device exhibits outstanding performance with a JSC of 21.45 mA cm−2, VOC of 1.077 V, FF of 77.57% and PCE of 17.91%, as shown in Fig. 4. Studies of device hysteresis and stability are provided in Supplementary Figs 6 and 7, respectively.

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