Elsevier

Applied Surface Science

Volume 389, 15 December 2016, Pages 540-546
Applied Surface Science

Using elemental Pb surface as a precursor to fabricate large area CH3NH3PbI3 perovskite solar cells

https://doi.org/10.1016/j.apsusc.2016.07.072Get rights and content

Highlights

  • The current study is the first report using elemental Pb surface as a precursor to fabricate perovskite solar cells.

  • This elemental Pb initiated in-situ reaction allows for the fabrication of large area and uniform perovskite thin films with long minority carrier lifetimes as good as the perovskite thin films obtained via common two-step method.

  • Such a solar cell device fabricated in an ambient atmosphere were found to be relatively stable upon storage for more than 200 days.

Abstract

The development of new chemical methods to prepare large area perovskite thin film solar cells is desirable for potential future industrial applications. In this paper, a novel fabrication of perovskite CH3NH3PbI3 thin films based on direct metal surface elemental reaction (DMSER) method in an ambient atmosphere is discussed. The as-prepared CH3NH3PbI3 thin films are highly pure and crystalline. Consequent Transient photovoltaic (TPV) tests were conducted and show that these thin films have a long minority carrier lifetime as good as the perovskite thin films obtained via common two-step method from the literature. Although there have been many studies that have developed perovskite solar cells (PSCs) during the past five years, the current study is the first report using elemental Pb as a precursor to fabricate perovskite solar cells, which were found to be relatively stable upon storage without encapsulation in glove box for more than 200 days. This Pb-initiated in-situ reaction allows for the fabrication of large area and uniform perovskite thin films. For example, in our preliminary studies, we have fabricated large area solar cell device samples (1.10 ± 0.05 cm2) and have evaluated their photovoltaic performance under standard conditions (AM 1.5, 100 mW cm−2).

Introduction

Lead halide perovskite crystals such as MAPbX3 (X = I, Br, Cl) evolved from dye-sensitized solar cells based on MAPbI3 which were first fabricated by Miyasaka group in 2009 [1]. Since then, lead halide perovskite crystals have been widely studied as light absorber in nanostructured heterojunction solar cells application [2], [3], [4], [5], [6]. Just 7 years later, the power conversion efficiency of perovskite solar cells have raised to above 20% [7]. Lead halide perovskite possess most of the crucial properties which required by the high performance and low cost solar cells. These properties include direct bandgap, high absorption coefficient, long carrier lifetime, low fundamental energy loss, ease fabrication and low production cost [8], [9].

In general, MAPbX3 crystals are synthesized by reaction of methylammonium iodide (MAX) with lead-containing precursor. PbI2 [10], [11], lead acetate [12], lead nitrate [13], lead oxide [14], [15], lead titanate [16], lead acetylacetone [17] and lead thiocyanate [18] have been developed to fabricate perovskite solar cells with high power conversion efficiencies. For fabricating a high quality perovskite thin film, variety of methods including spin coating [19], [20], [21], spray coating [22], vapor-assisted solution processing [23] and vapor deposition [24], [25] have been studied. Among these methods, spin coating lead compounds such as PbI2 and Pb(NO3)2 solution for perovskite solar cells fabrication has been widely used. However, this popular method randomly affects the perovskite thin film quality such as morphology and crystal size even at the same experimental condition. Better repeatability of preparing a large active area MAPbX3 thin film with high quality is still a challenge.

In our previous studies, we have successfully deplored a direct metal surface elemental reaction (DMSER) method to prepare various semiconductor thin films. Especially, a room temperature, in-situ elemental reaction method has been built for inorganic semiconductor thin films fabrication [26]. These films have been used for sun light harvest. In this study, we report a novel and facile method to fabricate high quality, large area perovskite thin film based on in-situ elemental reaction. According to this route, an elemental lead layer was deposited on substrate firstly and then in-situ reacted with a CH3NH3I solution or a mixed CH3NH3I and I2 solution at room temperature. This elemental Pb-based in-situ reaction allows for the fabrication of large area and uniform perovskite thin films. Based on the large area perovskite thin film, a large active area perovskite solar cell device has been assembled under ambient atmosphere with a 40 ± 3% relative humidity (RH). The subsequent performance tests have been carried out, and a power conversion efficiency of 3.08% was achieved in an un-optimized large area perovskite solar cell device (1.10 ± 0.05 cm2). In order to further study the elemental reaction based perovskite films, transient photovoltaic (TPV) was employed to measure the photoinduced charge carrier dynamics [27]. TPV results indicated that the photoinduced charge carrier life time of the Pb-based perovskite thin films was as good as the perovskite thin films which were fabricated by the conventional two-step deposition method in the literature [21]. To our knowledge, this is the first time of using elemental Pb as a precursor in perovskite solar cell researching. This idea of synthesis CH3NH3PbI3 thin film based on elemental Pb may provide a new way for large area and high performance perovskite solar cell fabrication.

Section snippets

Experimental

All reagents are purchased from China National Medicines Corporation Ltd. except special callouts.

Results and discussion

Previously, we have reported in-situ approaches to fabricate compound thin films of PbI2 [28], Ag2S [26], CuI [29], and Ag3CuS2 [30]. We found that using this in-situ approach facilitates the formation of compact and uniform compound thin films. In this work, the in-situ approach was used to prepare perovskite CH3NH3PbI3. Fig. 1 shows the fabrication process for the perovskite layers based on elemental Pb. First, an elemental lead layer was sputtered onto FTO-ZnO substrate. Then, the in-situ

Conclusion

The perovskite CH3NH3PbI3 material with highly purity and crystallization was successfully in-situ fabricated from elemental Pb thin film under high moisture condition (40% ± 3% RH). The thickness and area of the elemental Pb based perovskite thin film can be easily controlled. It benefits the fabrication of uniform and large area perovskite thin film for solar cell application. TPV measurements reveal that the elemental Pb-initiated perovskite thin film has a long minority carrier lifetime as

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21273192 and 61504117), Innovation Scientists and Technicians Troop Construction Projects of Henan Province (Grant No. 144200510014), Program for Innovative Research Team (in Science and Technology) in University of Henan Province (Grant No. 2012IRTSTHN021), Scientific Research Program of Xuchang University (No. 2015095), Program for Basis and Frontier Technology Research of Xuchang City (No.11).

References (36)

  • J.H. Noh et al.

    Nanostructured TiO2/CH3NH3PbI3 heterojunction solar cells employing spiro-OMeTAD/Co-complex as hole-transporting material

    J. Mater. Chem. A

    (2013)
  • W.S. Yang et al.

    High-performance photovoltaic perovskite layers fabricated through intramolecular exchange

    Sci. Rep.

    (2015)
  • S.D. Stranks et al.

    Electron–hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber

    Science

    (2013)
  • G.C. Xing et al.

    Long-range balanced electron- and hole-transport lengths in organic-inorganic CH3NH3PbI3

    Science

    (2013)
  • J. Qing et al.

    Chlorine incorporation for enhanced performance of planar perovskite solar cell based on lead acetate precursor

    ACS Appl. Mater. Interfaces

    (2015)
  • T.Y. Hsieh et al.

    Efficient perovskite solar cells fabricated using an aqueous lead nitrate precursor

    Chem. Commun.

    (2015)
  • J.H. Huang et al.

    Direct conversion of CH3NH3PbI3 from electrodeposited PbO for highly efficient planar perovskite solar cells

    Sci. Rep.

    (2015)
  • X.P. Cui et al.

    Electrodeposition of PbO and its in situ conversion to CH3NH3PbI3 for mesoscopic perovskite solar cells

    Chem. Commun.

    (2015)
  • Cited by (31)

    • Structural, elastic, electronic and optical properties of double perovskites Ba<inf>2</inf>NaXO<inf>6</inf> (X = Cl, Br, I): First-principles study

      2023, Materials Science in Semiconductor Processing
      Citation Excerpt :

      For example, research in solar cells has shown that perovskites have high carrier mobility, light absorption capacity, and power conversion efficiency (PCE) [6–10]. The most representative of this category is Pb-based perovskites [11–14]. But it is worth noting that once this type of perovskites is exposed to the air and water, it will become unstable, and there exists a risk of toxic ion Pb+ polluting the environment [15].

    • Sol-gel-processed yttrium-doped NiO as hole transport layer in inverted perovskite solar cells for enhanced performance

      2018, Applied Surface Science
      Citation Excerpt :

      Recently, organic-inorganic hybrid perovskite materials have attracted extremely research attention due to their excellent opto-electronic properties, such as strong light-absorption, long charge carrier lifetimes, high carrier mobility and long diffusion length and easy solution processing. Over the past few years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has rapidly increased from initial 3.8% to 22.1% [1–8], affirming a great potential for high-efficiency, low-cost photovoltaics. As well known, the architecture of PSCs can be generally classified into mesoscopic and planar structures in a regular (i.e., n-i-p) or inverted (i.e., p-i-n) geometry [9].

    • A strategy toward air-stable and high-performance ZnO-based perovskite solar cells fabricated under ambient conditions

      2018, Chemical Engineering Journal
      Citation Excerpt :

      For example, Liu and co-workers realized the fabrication of an efficient flexible PSCs via using room-temperature solution processed ZnO film as the ETL [27]. The group of Zheng fabricated stable PSCs based on ZnO nanorod as ETL under relatively high humidity [28,29]. The group of Yang reported an efficient solution-processed ZnO-based PSCs, which demonstrated an efficiency of up to 16.1% [30].

    • Hole-conductor-free perovskite solar cells prepared with carbon counter electrode

      2018, Applied Surface Science
      Citation Excerpt :

      Recently, organic-inorganic hybrid perovskite solar cell (PSC) has attracted intensive attention [1–8].

    • Investigation of Al <inf>2</inf> O <inf>3</inf> and ZrO <inf>2</inf> spacer layers for fully printable and hole-conductor-free mesoscopic perovskite solar cells

      2018, Applied Surface Science
      Citation Excerpt :

      These characteristics are conducive to the further development of PSCs. In recent years, photoelectric conversion efficiency (PCE) of PSCs has been raised from 3.8% to more than 20% [5–14]. Hole transport materials (HTM) play an important role to facilitate the hole transport from perovskite layer to counter electrode (CE) in PSCs [15,16].

    View all citing articles on Scopus
    View full text