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Fullerene (C60)-modulated surface evolution in CH3NH3PbI3 and its role in controlling the performance of inverted perovskite solar cells

Authors:
Mulayam Singh Patel at University of Allahabad
Mulayam Singh Patel
Dhirendra K. Chaudhary at Veer Bahadur Singh Purvanchal University
Dhirendra K. Chaudhary
Pankaj Kumar
Pankaj Kumar
Pankaj Kumar
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Lokendra Kumar at University of Allahabad
Lokendra Kumar
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Abstract and Figures

We report here the effect of fullerene (C60) incorporation on the growth of CH3NH3PbI3 perovskite crystals and the effect on photovoltaic performance of perovskite solar cells (PSCs) prepared in inverse geometry. Incorporation of C60 induced the growth of larger gains and compact thin film of perovskite with reduced defects, which led to its enhanced photovoltaic performance. Apart from that, C60 also participates in transportation and collection of photo-generated electrons. The optimum incorporation of C60 resulted in an impressive improvement in the power conversion efficiency (PCE) of champion PSC from 9.2 to 12.8%. Moreover, the C60-doped PSCs exhibited improved air stability compared to undoped devices. The enhanced PCE in C60-doped PSCs is a result of enhanced optical absorption and separation of photo-generated charge and their transportation in the active layer. Since the size of C60 molecules is of the order of nm, they easily get filled into the perovskite voids and facilitate another percolation path ways for charge carriers to transport and suppress the recombination losses via passivating the recombination centres in perovskite layers. The compact perovskite layer with larger grains led to reduced inter-granular grain boundaries with reduced defects, which restricts the fast diffusion of moisture into active layer and resulted in improved stability in device performance.
FE-SEM micrographs of PbI 2 films grown from a pure PbI 2 solution and b fullerene derivative-doped PbI 2 solution in DMF [17]
FE-SEM micrographs of PbI 2 films grown from a pure PbI 2 solution and b fullerene derivative-doped PbI 2 solution in DMF [17]
… 
a Photograph of PbI2 and PbI2:C60 precursor solutions with different C60 concentrations; (i) 0 (ii) 0.25 mg/ml (iii) 0.50 mg/ml and (iv) 1.0 mg/ml, b photograph of PEDOT:PSS thin films, c photograph of just deposited PbI2 and PbI2:C60 thin films, d photograph of PbI2 and PbI2:C60 thin films after heating at 100 °C for 2 min., e photograph of PbI2 and PbI2:C60 films after MAI deposition, f photograph of perovskite films with and without C60. FE-SEM micrograph of g CH3NH3PbI3, h CH3NH3PbI3:C60 (0.25 mg), i CH3NH3PbI3:C60 (0.50 mg) and j CH3NH3PbI3:C60 (1.0 mg) thin films after heating at 90 °C for 60 min
a Photograph of PbI2 and PbI2:C60 precursor solutions with different C60 concentrations; (i) 0 (ii) 0.25 mg/ml (iii) 0.50 mg/ml and (iv) 1.0 mg/ml, b photograph of PEDOT:PSS thin films, c photograph of just deposited PbI2 and PbI2:C60 thin films, d photograph of PbI2 and PbI2:C60 thin films after heating at 100 °C for 2 min., e photograph of PbI2 and PbI2:C60 films after MAI deposition, f photograph of perovskite films with and without C60. FE-SEM micrograph of g CH3NH3PbI3, h CH3NH3PbI3:C60 (0.25 mg), i CH3NH3PbI3:C60 (0.50 mg) and j CH3NH3PbI3:C60 (1.0 mg) thin films after heating at 90 °C for 60 min
… 
FE-SEM micrograph of the CH3NH3PbI3:C60 film with C60 concentration of 1.5 mg/ml
FE-SEM micrograph of the CH3NH3PbI3:C60 film with C60 concentration of 1.5 mg/ml
… 
a X-ray diffractogram, b UV–Visible absorbance spectra, c Photoluminescence spectra (excitation wavelength 557 nm) of pure CH3NH3PbI3 and CH3NH3PbI3:C60 films with different concentrations of C60 and d Schematic representation of charge transfer mechanism in CH3NH3PbI3:C60 perovskite films
a X-ray diffractogram, b UV–Visible absorbance spectra, c Photoluminescence spectra (excitation wavelength 557 nm) of pure CH3NH3PbI3 and CH3NH3PbI3:C60 films with different concentrations of C60 and d Schematic representation of charge transfer mechanism in CH3NH3PbI3:C60 perovskite films
… 
Schematic representation of a device architecture and b energy level of the PSCs. cJ–V characteristics of the devices under standard illumination conditions, d Nyquist plots and e hysteresis index plot of the PSCs with different concentrations of C60. f Histogram plot of the efficiency of devices fabricated without and with 1 mg/ml of C60 concentration
+2
Schematic representation of a device architecture and b energy level of the PSCs. cJ–V characteristics of the devices under standard illumination conditions, d Nyquist plots and e hysteresis index plot of the PSCs with different concentrations of C60. f Histogram plot of the efficiency of devices fabricated without and with 1 mg/ml of C60 concentration
… 
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Vol:.(1234567890)
Journal of Materials Science: Materials in Electronics (2020) 31:11150–11158
https://doi.org/10.1007/s10854-020-03664-5
1 3
Fullerene (C60)‑modulated surface evolution in CH3NH3PbI3 andits role
incontrolling theperformance ofinverted perovskite solar cells
M.S.Patel1· DhirendraK.Chaudhary1,3· PankajKumar2· LokendraKumar1
Received: 27 January 2020 / Accepted: 22 May 2020 / Published online: 28 May 2020
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
We report here the effect of fullerene (C60) incorporation on the growth of CH3NH3PbI3 perovskite crystals and the effect
on photovoltaic performance of perovskite solar cells (PSCs) prepared in inverse geometry. Incorporation of C60 induced
the growth of larger gains and compact thin film of perovskite with reduced defects, which led to its enhanced photovoltaic
performance. Apart from that, C60 also participates in transportation and collection of photo-generated electrons. The opti-
mum incorporation of C60 resulted in an impressive improvement in the power conversion efficiency (PCE) of champion
PSC from 9.2 to 12.8%. Moreover, the C60-doped PSCs exhibited improved air stability compared to undoped devices. The
enhanced PCE in C60-doped PSCs is a result of enhanced optical absorption and separation of photo-generated charge and
their transportation in the active layer. Since the size of C60 molecules is of the order of nm, they easily get filled into the
perovskite voids and facilitate another percolation path ways for charge carriers to transport and suppress the recombination
losses via passivating the recombination centres in perovskite layers. The compact perovskite layer with larger grains led to
reduced inter-granular grain boundaries with reduced defects, which restricts the fast diffusion of moisture into active layer
and resulted in improved stability in device performance.
1 Introduction
Perovskite solar cells (PSCs) technology is one of the fast-
est growing photovoltaic technologies as they have shown
very high efficiency with high cost-effectiveness [1–3].
The potential of this technology could be understood
from the improvement in its power conversion efficiency
(PCE) itself, which reached to a record value of ~ 25.2%
just within few years [4]. Moreover, they offer low pro-
duction cost, light weight and feasibility with sheet to
sheet and roll-to-roll processing on flexible substrates.
However, this technology is still far from the market as
its overall performance is still not high enough to sought
marketplace. Some of the issues that have been observe to
affect their performance significantly are the grain size of
perovskites crystallites, compactness of thin films, charge
carriers traps, hysteresis in the I–V characteristics and
poor stability [5–7]. It is important to note that usually
high efficiency PSCs are prepared in a well-controlled
inert environment and from perspective of commerciali-
zation they should be prepared in air. In recent years, a
large volume of research activities have been carried out
regarding formation of pin hole free compact perovskite
layers [8–19]. It is a well reported fact that the compact
and dense perovskite films without pinholes will facilitates
the better pathway and reduces the charge carrier recom-
bination between photoactive and charge transport layers
[20–22]. To improve the quality of perovskite thin films
and control the crystallization rate, many researchers have
used additive or solvent engineering and solvent vapour
treatment methods, viz. Methanol, Ammonium chloride
(NH4Cl), Lithium chloride (LiCl), 1,8-diiodooctane (DIO),
Water, Methylamine (CH3NH2), pseudohalide Lead(II)
thiocyanate (Pb(SCN)2) and N,N-Dimethylmethanamide
M. S. Patel and Dhirendra K. Chaudhary are contributed equally
to this work.
* Lokendra Kumar
lkumarau@gmail.com
1 Molecular Electronics Research Laboratory, Physics
Department, University ofAllahabad, Prayagraj,
U.P.211002, India
2 CSIR-National Physical Laboratory, Dr. K. S. Krishnan
Marg, NewDelhi110012, India
3 Present Address: Centre forRenewable Energy,
Prof. Rajendra Singh (Rajju Bhaiya) Institute ofPhysical
Sciences forstudy andResearch, Veer Bahadur Singh
Purvanchal University, Jaunpur222001, India
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Perovskite materials have attracted immense attention as a new class of materials for next-generation low-cost, high-performance optoelectronic and photonic devices [1][2][3][4][5][6][7][8]. The rapid development in this field has resulted in many categories of perovskite materials, out of which lead halide perovskites (LHPs) have received significant attention due to their semiconducting and photosensitive properties. ...
... The LHPs can broadly be classified into organic-inorganic and all-inorganic perovskite materials. Despite the unique optical and electrical properties of LHPs, the stability of organic-inorganic perovskite is still a primary concern [2, 3,11,12]. Significant attempts have been made to circumvent the instability of organic-inorganic perovskites, and it has been reported that the replacement of organic 'A' site cation in LHP with inorganic 'Cs' shows better chemical and thermal stability in the ambient atmosphere [13,14]. ...
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... Furthermore, this technique can be easily tested and visualized, permitting a good opportunity for effective analytical analysis. Thus, the photoinduced electron transfer in the conducting-polymer-C 60 composites was evaluated using infrared photoexcitation spectroscopy [9]; the photoinduced electron transfer in the C 60 -doped poly(N-vinylcarbazole) films was revealed by picosecond laser photolysis in [12]; the significant effect of fullerene doping on the absorption edge shift was determined for the 2cyclooctylamino-5-nitropyridine nanocomposite in [15]; refractive grating was recorded in It should be noted that the doping process of the different materials using the perspective nanostructures-fullerenes, carbon nanotubes (CNTs), quantum dots (QDs), graphene oxides (GrO), etc.-provokes the dramatic change in the basic physical-chemical material properties vital for the improvement of the technical device parameters [21][22][23][24][25][26][27][28][29][30][31][32][33]. Thus, the role of fullerene C60 in controlling the performance of inverted perovskite solar cells was shown in [21]. ...
... Thus, the photoinduced electron transfer in the conducting-polymer-C 60 composites was evaluated using infrared photoexcitation spectroscopy [9]; the photoinduced electron transfer in the C 60 -doped poly(N-vinylcarbazole) films was revealed by picosecond laser photolysis in [12]; the significant effect of fullerene doping on the absorption edge shift was determined for the 2cyclooctylamino-5-nitropyridine nanocomposite in [15]; refractive grating was recorded in It should be noted that the doping process of the different materials using the perspective nanostructures-fullerenes, carbon nanotubes (CNTs), quantum dots (QDs), graphene oxides (GrO), etc.-provokes the dramatic change in the basic physical-chemical material properties vital for the improvement of the technical device parameters [21][22][23][24][25][26][27][28][29][30][31][32][33]. Thus, the role of fullerene C60 in controlling the performance of inverted perovskite solar cells was shown in [21]. Some fullerene derivatives have been applied for solar energy and diode applications. ...
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  • Sep 2018
  • ORG ELECTRON
Perovskite solar cells (PSCs) are promising low-cost photovoltaic technologies with high solar-to-electric power conversion efficiency (PCE). Preparation of high-quality perovskite thin films is key to achieve high performance for PSCs. In this work, a small amount of fullerene (C60) is added to toluene in the antisolvent dripping process. The resulting C60-containing perovskite solar cells show better stability, PCE, and reproducibility than the device fabricated by using only toluene as an antisolvent. C60 adheres to the pinhole and grain boundaries of perovskite film, improves perovskite crystallinity, and enhances absorption without changing the thickness of the film. It also plays a passivation role on the surface of perovskite film and prevents the migration of I and Pb elements. The change of the morphology and the passivation of the interface increase the FF and JSC of C60-containing device. The best PCE of 19.8% is obtained. The PCE of encapsulated PSCs still maintains 70% of its initial value after 1000 h continuous full sun illumination.
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Enhanced photovoltage for inverted planar heterojunction perovskite solar cells
Article
  • Jun 2018
Perovskite layers make the grade Inverted planar perovskite solar cells offer opportunities for a simplified device structure compared with conventional mesoporous titanium oxide interlayers. However, their lower open-circuit voltages result in lower power conversion efficiencies. Using mixed-cation lead mixed-halide perovskite and a solution-processed secondary growth method, Luo et al. created a surface region in the perovskite film that inhibited nonradiative charge-carrier recombination. This kind of solar cell had comparable performance to that of conventional cells. Science , this issue p. 1442
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PbI2/CH3NH3Cl Mixed Precursor–Induced Micrometer‐Scale Grain Perovskite Film and Room‐Temperature Film Encapsulation toward High Efficiency and Stability of Planar Perovskite Solar Cells
Article
  • Jun 2018
The power conversion efficiency and the stability are the most important figures of merit for perovskite solar cells which attract increasing attention in recent years. Herein, the growth of high‐quality perovskite films with micrometer‐scale grain size through sequential deposition is first reported using PbI2/CH3NH3Cl mixed precursors during the first step of deposition. The amount of CH3NH3Cl in the precursor has a great influence on the morphology of perovskite films and the device performance. Compared with traditional sequential deposition with pure PbI2 in the first step, this method renders the perovskite solar cells with an improved power conversion efficiency up to 18.7% and reduced hysteresis. In addition, the fluorinated carbon film prepared at room temperature is reported as an encapsulation layer for perovskite solar cells. The compact and hydrophobic thin film can effectively isolate the device from moisture and oxygen, leading to the largely improved stability in the air. This study not only reveals the effect of chlorine doping on perovskite film formation in the first step of sequential deposition, but also provides a new film encapsulation strategy to improve the device stability in ambient air toward future application. A modified sequential deposition using PbI2/CH3NH3Cl mixed precursor is provided during the first step of deposition to synthesize pinhole‐free iodide–chloride perovskite films with micrometer‐scale grain size and a room temperature–processed protection technology to simultaneously improve the power conversion efficiency and stability of planar perovskite solar cells.
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Improving the Quality of CH 3 NH 3 PbI 3 Films via Chlorobenzene Vapor Annealing
Article
  • May 2018
Crystalline quality of perovskite materials is crucial to the photovoltaic performance of perovskite solar cells (PSCs). Herein, a chlorobenzene (CB) vapor annealing approach is introduced to prepare high quality CH3NH3PbI3 perovskite films. During the annealing process, the CB vapor diffuses into the CH3NH3PbI3 films and dissolves residual DMSO solvent, and volatilizes out of the CH3NH3PbI3 films to help residual DMSO solvent evaporate. This promotes the crystallization of the CH3NH3PbI3 films and the small grains integrate and merge together to form larger grains. The fabricated planar perovskite solar cells based on the CB vapor annealed CH3NH3PbI3 films have an average power conversion efficiency (PCE) of 17.9% and the highest PCE of 18.5%. In contrast, the planar perovskite solar cells fabricated using the traditional‐annealed CH3NH3PbI3 films give an average PCE of 16.4% and the highest PCE of 16.8%. The enhanced photovoltaic performance is due to the CH3NH3PbI3 film quality improvement, with higher crystallinity, larger grains, and longer carrier lifetime.
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