Perovskite solar cells have been rapidly developed in the past ten years. It was demonstrated that the interfacial layer plays an important role in device performance of perovskite solar cells. In this study, we report utilization of a photoinitiation-crosslinked zwitterionic polymer, namely dextran with carboxybetaine modified by methacrylate (Dex-CB-MA), as an interfacial layer to improve the film morphology of the CH 3 NH 3 PbI 3 photoactive layer and the interfacial contact between the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole extraction layer and CH 3 NH 3 PbI 3 photoactive layer. It is found that the Dex-CB-MA thin layer forms a better band alignment between the PEDOT:PSS hole extraction layer and CH 3 NH 3 PbI 3 photoactive layer, and improves the crystallization of the CH 3 NH 3 PbI 3 photoactive layer, resulting in efficient charge carrier transport. As a result, perovskite solar cells with the PEDOT:PSS/Dex-CB-MA hole extraction layer exhibit more than 30% enhancement in efficiency and dramatically boosted stability as compared with that with the PEDOT:PSS hole extraction layer. Our studies provide an effective and facile way to fabricate stable perovskite solar cells with high power conversion efficiency.
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Chemical and Structural Degradation of CH 3 NH 3 PbI 3 Propagate from PEDOT:PSS Interface in the Presence of Humidity
Understanding interfacial reactions that occur between the active layer and charge‐transport layers can extend the stability of perovskite solar cells. In this study, the exposure of methylammonium lead iodide (CH3NH3PbI3) thin films prepared on poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)‐coated glass to 70% relative humidity (R.H.) leads to a perovskite crystal structure change from tetragonal to cubic within 2 days. Interface‐sensitive photoluminescence measurements indicate that the structural change originates at the PEDOT:PSS/perovskite interface. During exposure to 30% R.H., the same structural change occurs over a much longer time scale (>200 days), and a reflection consistent with the presence of (CH3)2NH2PbI3is detected to coexist with the cubic phase by X‐ray diffraction pattern. The authors propose that chemical interactions at the PEDOT:PSS/perovskite interface, facilitated by humidity, promote the formation of dimethylammonium, (CH3)2NH2+. The partial A‐site substitution of CH3NH3+for (CH3)2NH2+to produce a cubic (CH3NH3)1−
- NSF-PAR ID:
- 10449882
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 8
- Issue:
- 16
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract In the past years, hybrid perovskite materials have attracted great attention due to their superior optoelectronic properties. In this study, the authors report the utilization of cobalt (Co2+) to partially substitute lead (Pb2+) for developing novel hybrid perovskite materials, CH3NH3Pb1‐
x Cox I3(wherex is nominal ratio,x = 0, 0.1, 0.2 and 0.4). It is found that the novel perovskite thin films possess a cubic crystal structure with superior thin film morphology and larger grain size, which is significantly different from pristine thin film, which possesses the tetragonal crystal structure, with smaller grain size. Moreover, it is found that the 3d orbital of Co2+ensures higher electron mobilities and electrical conductivities of the CH3NH3Pb1‐x Cox I3thin films than those of pristine CH3NH3Pb4thin film. As a result, a power conversion efficiency of 21.43% is observed from perovskite solar cells fabricated by the CH3NH3Pb0.9Co0.1I3thin film. Thus, the utilization of Co, partially substituting for Pb to tune physical properties of hybrid perovskite materials provides a facile way to boost device performance of perovskite solar cells. -
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Abstract Next‐generation electronics and energy technologies can now be developed as a result of the design, discovery, and development of novel, environmental friendly lead (Pb)‐free ferroelectric materials with improved characteristics and performance. However, there have only been a few reports of such complex materials’ design with multi‐phase interfacial chemistry, which can facilitate enhanced properties and performance. In this context, herein, novel lead‐free piezoelectric materials (1‐
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Tin halide perovskites are among the candidates for replacing lead-based ones for less toxicity and comparable optical properties. However, stability remains a challenge due to the easier oxidation of Sn 2+ than Pb 2+ . Here, for the first time, we applied the ligand-assisted reprecipitation method to synthesize CH(NH 2 ) 2 SnI 3 (FASnI 3 ) orthorhombic perovskite nanocrystals with an average diameter of 7.7 nm and a photoluminescence emission at 825 [Formula: see text] 2 nm (1.5 eV). The influence of synthesis parameters, including precursor solvent, precipitation media, temperature, and time on optical properties of nanocrystals, was studied. By incorporating SnF 2 , the stability of the nanocrystals was improved, and the oxidation from FASnI 3 to FA 2 SnI 6 was significantly delayed, which was quantitively demonstrated and confirmed by observing the characteristic diffraction peaks of the perovskite phase using x-ray diffraction at various exposure time to air. The addition of SnF 2 is optimized to be 6%. The FASnI 3 nanocrystals stayed stable for at least 265 days under N 2 storage at room temperature and relative humidity of 20%.more » « less
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Abstract Organic–inorganic hybrid perovskites (OIHPs) have been explosively investigated mainly due to their potential applications in optoelectronics. Despite the electronic charge transport, phenomena regarding the spin‐polarized electronic transport in OIHPs‐based spintronic devices and the role of ferromagnet/OIHP spinterfaces remain unclear. In this work, the spin injection, accumulation, transport, and detection at room temperature for a vertical perovskite spin valve (PeSV) consisting of Ni/CH3NH3PbI3−
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