Amide Additives Induced a Fermi Level Shift To Improve the Performance of Hole-Conductor-Free, Printable Mesoscopic Perovskite Solar Cells

Liu, Shuang; Li, Sheng; Wu, Jiawen; Wang, Qifei; Yue, Ming; Zhang, Deyi; Sheng, Yusong; Hu, Yue; Rong, Yaoguang; Mei, Anyi; Han, Hongwei

doi:10.1021/acs.jpclett.9b02463

Cited by 63 publications

(66 citation statements)

References 59 publications

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“…The increased grain size is attributed to the formation of a PbI 2 ‐DFPDA adduct, which increases the activation energy and decreases the number of nucleations, as discussed before. [ 21,32,33 ] Water contact‐angle measurements are carried out to investigate the ability of the perovskite films to resist water (Figure 4c). With the increase of DFPDA concentration, the contact angle of the perovskite film increases.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Enhancement for Highly Stable and Efficient Perovskite Solar Cells

Cai

Cui

Chen

et al. 2020

Adv Funct Materials

285

273

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With a certified efficiency as high as 25.2%, perovskite has taken the crown as the highest efficiency thin film solar cell material. Unfortunately, serious instability issues must be resolved before perovskite solar cells (PSCs) are commercialized. Aided by theoretical calculation, an appropriate multifunctional molecule, 2,2‐difluoropropanediamide (DFPDA), is selected to ameliorate all the instability issues. Specifically, the carbonyl groups in DFPDA form chemical bonds with Pb2+ and passivate under‐coordinated Pb2+ defects. Consequently, the perovskite crystallization rate is reduced and high‐quality films are produced with fewer defects. The amino groups not only bind with iodide to suppress ion migration but also increase the electron density on the carbonyl groups to further enhance their passivation effect. Furthermore, the fluorine groups in DFPDA form both an effective barrier on the perovskite to improve its moisture stability and a bridge between the perovskite and HTL for effective charge transport. In addition, they show an effective doping effect in the HTL to improve its carrier mobility. With the help of the combined effects of these groups in DFPDA, the PSCs with DFPDA additive achieve a champion efficiency of 22.21% and a substantially improved stability against moisture, heat, and light.

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Section: Resultsmentioning

confidence: 99%

Multifunctional Enhancement for Highly Stable and Efficient Perovskite Solar Cells

Cai

Cui

Chen

et al. 2020

Adv Funct Materials

285

273

View full text Add to dashboard Cite

show abstract

“…Also, the introduction of PbAc 2 /MAI led to lower crystallinity, which was more favorable to obtain phase-pure α-FAPbI 3 perovskite. [15] Time-resolved photoluminescence (TRPL) and steady-state PL spectra were measured to investigate the influences of different lead precursors on the charge carrier extraction at perovskite/ mp-TiO 2 interface and charge carrier recombination in bulk perovskites, [44,45] as shown in Figure 4. The TRPL decay was fitted with biexponential function, and the detailed fitting parameters are listed in Table S3, Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Crystallization Control of Methylammonium‐Free Perovskite in Two‐Step Deposited Printable Triple‐Mesoscopic Solar Cells

Liu

et al. 2020

Solar RRL

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The evolution from the original methylammonium (MA)‐ to formamidinium (FA)‐dominated perovskite makes a crucial contribution to improve the photoelectric performance of perovskite solar cells (PSCs) in a decade. However, to obtain α‐FAPbI3, annealing temperature above 100 °C is essential. In addition, it is still challenging to deposit a uniform and high‐quality FA‐based perovskite absorber in printable triple‐mesoscopic PSC due to the complicated mesoscopic structure. Herein, a low‐temperature, two‐step sequential deposition method is used for pure FAPbI3 perovskite in printable triple‐mesoscopic PSC. By using different lead sources, the crystallization and morphology of lead iodide (PbI2) are finely controlled, which modulates the crystallization and pore filling of perovskite in mesoscopic structure. The improved interface contact promotes the transfer of charge carrier from perovskite to TiO2. With the further introduction of cesium bromide (CsBr) into lead precursor, a power conversion efficiency of 16.24% is achieved. This study provides a deeper understanding of the pore filling and crystallization for both PbI2 and perovskite, and helps explore and optimize the deposition process of perovskite in mesoscopic structure.

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“…Figure a displays electric impedance spectroscopy (EIS) measurements of the fabricated PSC devices measured in dark at a bias of −1.05 V. The equivalent circuit model is shown in the inset and includes a series resistance ( R s ) and a recombination resistance ( R rec ) in parallel with a chemical capacitance ( C µ ) at the TiO 2 /perovskite/HTL interface 54–58. It can be seen that GA‐modified PSC device shows the largest R rec (363 Ω) compared to the control device (277 Ω) and TGA‐modified PSC device (172 Ω).…”

Section: Resultsmentioning

confidence: 99%

Solvent Engineering Using a Volatile Solid for Highly Efficient and Stable Perovskite Solar Cells

Cui

et al. 2020

Advanced Science

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A strategy for efficaciously regulating perovskite crystallinity is proposed by using a volatile solid glycolic acid (HOCH2COOH, GA) in an FA0.85MA0.15PbI3 (FA: HC(NH2)2; MA: CH3NH3) perovskite precursor solution that is different from the common additive approach. Accompanied with the first dimethyl sulfoxide sublimation process, the subsequent sublimation of GA before 150 °C in the FA0.85MA0.15PbI3 perovskite film can artfully regulate the perovskite crystallinity without any residual after annealing. The improved film formation upon GA modification induced by the strong interaction between GA and Pb2+ delivers a champion power conversion efficiency (PCE) as high as 21.32%. In order to investigate the role of volatility in perovskite solar cells (PSCs), nonvolatile thioglycolic acid (HSCH2COOH, TGA) with a similar structure to GA is utilized as an additive reference. Large perovskite grains are obtained by TGA modification but with obvious pinholes, which directly leads to an increased defect density accompanied by a decline in PCE. Encouragingly, the champion PCE achieved for GA‐based PSC device (21.32%) is almost 13% or 20% higher than those of the control device or TGA‐based device. In addition, GA‐modified PSCs exhibit the best stability in light‐, thermal‐, and humidity‐based tests due to the improved film formation.

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Amide Additives Induced a Fermi Level Shift To Improve the Performance of Hole-Conductor-Free, Printable Mesoscopic Perovskite Solar Cells

Cited by 63 publications

References 59 publications

Multifunctional Enhancement for Highly Stable and Efficient Perovskite Solar Cells

Multifunctional Enhancement for Highly Stable and Efficient Perovskite Solar Cells

Crystallization Control of Methylammonium‐Free Perovskite in Two‐Step Deposited Printable Triple‐Mesoscopic Solar Cells

Solvent Engineering Using a Volatile Solid for Highly Efficient and Stable Perovskite Solar Cells

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