Evaporation-Induced Self-Assembly of Semi-Crystalline PbI2(DMSO) Complex Films as a Facile Route to Reproducible and Efficient Planar p-i-n Perovskite Solar Cells

MRS Advances ◽  
2018 ◽  
Vol 3 (32) ◽  
pp. 1807-1817 ◽  
Author(s):  
Brandon Dunham ◽  
Vivek Vattipalli ◽  
Christos Dimitrakopoulos

ABSTRACTHigh quality active layers for hybrid organic-inorganic perovskite solar cells are essential for achieving maximum device performance. However, perovskite active layers in solar cells are frequently prepared with unoptimized processes that lead to layers of inferior quality. This is often the case when research focuses on other aspects of the solar cell device, such as device design and architecture, carrier transport layers, electrodes, interlayers, etc. In this study, a single-step spin-coating method was used to prepare semi-crystalline PbI2(DMSO) complex films via evaporation-induced self-assembly. These optimized intermediate films were then used to form homogeneous methylammonium lead iodide (MAPbI3) perovskite films of optimum thickness (ca. 400 nm) with uniform surface coverage, good crystallinity, high purity, and grain sizes up to one micron, by employing a sequential deposition process involving intramolecular exchange between the PbI2(DMSO) complex film and a methylammonium iodide (MAI) layer deposited on top of it. We found that for certain ranges of MAI concentration, the formation of optimal-quality perovskite active layers was independent of MAI concentration, so long as MAI deposition occurred at specific corresponding spin speeds. Planar p-i-n perovskite solar cells comprising the optimized active layers were fabricated, and they exhibited negligible hysteresis and a maximum power conversion efficiency (PCE) of 16.72%, without any additional compositional and interfacial engineering. The latter can be used in the future to further enhance the PCE. These findings demonstrate the importance of an optimized perovskite active layer for reproducibly fabricating high-efficiency planar p-i-n photovoltaic devices. Additionally, the simplicity of the PbI2(DMSO) complex film preparation and the versatility of the MAI deposition with this fabrication method further enhances the potential of this material for large-scale processing.

MRS Advances ◽  
2018 ◽  
Vol 3 (55) ◽  
pp. 3237-3242 ◽  
Author(s):  
Zahrah S. Almutawah ◽  
Suneth C. Watthage ◽  
Zhaoning Song ◽  
Ramez H. Ahangharnejhad ◽  
Kamala K. Subedi ◽  
...  

ABSTRACTMethods of obtaining large grain size and high crystallinity in absorber materials play an important role in fabrication of high-performance methylammonium lead iodide (MAPbI3) perovskite solar cells. Here we study the effect of adding small concentrations of Cd2+, Zn2+, and Fe2+salts to the perovskite precursor solution used in the single-step solution fabrication process. Enhanced grain size and crystallinity in MAPbI3 films were obtained by using 0.1% of Cd2+ or Zn2+in the precursor solution. Consequently, solar cells constructed with Cd- and Zn-doped perovskite films show a significant improvement in device performance. These results suggest that the process may be an effective and facile method to fabricate high-efficiency perovskite photovoltaic devices.


2019 ◽  
Author(s):  
Sofia Masi ◽  
Carlos Echeverría-Arrondo ◽  
Salim K.P. Muhammed ◽  
Thi Tuyen Ngo ◽  
Perla F. Méndez ◽  
...  

<b>The extraordinary low non-radiative recombination and band gap versatility of halide perovskites have led to considerable development in optoelectronic devices. However, this versatility is limited by the stability of the perovskite phase, related to the relative size of the different cations and anions. The most emblematic case is that of formamidinium lead iodine (FAPI) black phase, which has the lowest band gap among all 3D lead halide perovskites, but quickly transforms into the non-perovskite yellow phase at room temperature. Efforts to optimize perovskite solar cells have largely focused on the stabilization of FAPI based perovskite structures, often introducing alternative anions and cations. However, these approaches commonly result in a blue-shift of the band gap, which limits the maximum photo-conversion efficiency. Here, we report the use of PbS colloidal quantum dots (QDs) as stabilizing agent for the FAPI perovskite black phase. The surface chemistry of PbS plays a pivotal role, by developing strong bonds with the black phase but weak ones with the yellow phase. As a result, stable FAPI black phase can be formed at temperatures as low as 85°C in just 10 minutes, setting a record of concomitantly fast and low temperature formation for FAPI, with important consequences for industrialization. FAPI thin films obtained through this procedure preserve the original low band gap of 1.5 eV, reach a record open circuit potential (V<sub>oc</sub>) of 1.105 V -91% of the maximum theoretical V<sub>oc</sub>- and preserve high efficiency for more than 700 hours. These findings reveal the potential of strategies exploiting the chemi-structural properties of external additives to relax the tolerance factor and optimize the optoelectronic performance of perovskite materials.</b>


Science ◽  
2020 ◽  
Vol 370 (6512) ◽  
pp. 108-112 ◽  
Author(s):  
Gwisu Kim ◽  
Hanul Min ◽  
Kyoung Su Lee ◽  
Do Yoon Lee ◽  
So Me Yoon ◽  
...  

High-efficiency lead halide perovskite solar cells (PSCs) have been fabricated with α-phase formamidinium lead iodide (FAPbI3) stabilized with multiple cations. The alloyed cations greatly affect the bandgap, carrier dynamics, and stability, as well as lattice strain that creates unwanted carrier trap sites. We substituted cesium (Cs) and methylenediammonium (MDA) cations in FA sites of FAPbI3 and found that 0.03 mol fraction of both MDA and Cs cations lowered lattice strain, which increased carrier lifetime and reduced Urbach energy and defect concentration. The best-performing PSC exhibited power conversion efficiency >25% under 100 milliwatt per square centimeter AM 1.5G illumination (24.4% certified efficiency). Unencapsulated devices maintained >80% of their initial efficiency after 1300 hours in the dark at 85°C.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 295
Author(s):  
Tianzhao Dai ◽  
Qiaojun Cao ◽  
Lifeng Yang ◽  
Mahmoud Aldamasy ◽  
Meng Li ◽  
...  

Perovskite solar cells (PSCs) have received a great deal of attention in the science and technology field due to their outstanding power conversion efficiency (PCE), which increased rapidly from 3.9% to 25.5% in less than a decade, comparable to single crystal silicon solar cells. In the past ten years, much progress has been made, e.g. impressive ideas and advanced technologies have been proposed to enlarge PSC efficiency and stability. However, this outstanding progress has always been referred to as small-area (<0.1 cm2) PSCs. Little attention has been paid to the preparation processes and their micro-mechanisms for large-area (>1 cm2) PSCs. Meanwhile, scaling up is an inevitable way for large-scale application of PSCs. Therefore, we firstly summarize the current achievements for high efficiency and stability large-area perovskite solar cells, including precursor composition, deposition, growth control, interface engineering, packaging technology, etc. Then we include a brief discussion and outlook for the future development of large-area PSCs in commercialization.


2021 ◽  
pp. 2102492
Author(s):  
Yeonghun Yun ◽  
Devthade Vidyasagar ◽  
Minho Lee ◽  
Oh Yeong Gong ◽  
Jina Jung ◽  
...  

APL Materials ◽  
2014 ◽  
Vol 2 (8) ◽  
pp. 081504 ◽  
Author(s):  
C. Momblona ◽  
O. Malinkiewicz ◽  
C. Roldán-Carmona ◽  
A. Soriano ◽  
L. Gil-Escrig ◽  
...  

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Aurelien M. A. Leguy ◽  
Jarvist Moore Frost ◽  
Andrew P. McMahon ◽  
Victoria Garcia Sakai ◽  
W. Kockelmann ◽  
...  

Abstract Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3 + ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ∼14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1–200-ps time window. Monte Carlo simulations of interacting CH3NH3 + dipoles realigning within a 3D lattice suggest that the scattering measurements may be explained by the stabilization of CH3NH3 + in either antiferroelectric or ferroelectric domains. Collective realignment of CH3NH3 + to screen a device’s built-in potential could reduce photovoltaic performance. However, we estimate the timescale for a domain wall to traverse a typical device to be ∼0.1–1 ms, faster than most observed hysteresis.


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