scholarly journals Improving the Morphology of the Perovskite Absorber Layer in Hybrid Organic/Inorganic Halide Perovskite MAPbI3 Solar Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
I. J. Ogundana ◽  
S. Y. Foo

Recently, perovskite solar cells have attracted tremendous attention due to their excellent power conversion efficiency, low cost, simple fabrications, and high photovoltaic performance. Furthermore, the perovskite solar cells are lightweight and possess thin film and semitransparency. However, the nonuniformity in perovskite layer constitutes a major setback to the operation mechanism, performance, reproducibility, and degradation of perovskite solar cells. Therefore, one of the main challenges in planar perovskite devices is the fabrication of high quality films with controlled morphology and least amount of pin-holes for high performance thin film perovskite devices. The poor reproducibility in perovskite solar cells hinders the accurate fabrication of practical devices for use in real world applications, and this is primarily as a result of the inability to control the morphology of perovskites, leading to large variability in the characteristics of perovskite solar cells. Hence, the focus of research in perovskites has been mostly geared towards improving the morphology and crystallization of perovskite absorber by selecting the optimal annealing condition considering the effect of humidity. Here we report a controlled ambient condition that is necessary to grow uniform perovskite crystals. A best PCE of 7.5% was achieved along with a short-circuit current density of 15.2 mA/cm2, an open-circuit voltage of 0.81 V, and a fill factor of 0.612 from the perovskite solar cell prepared under 60% relative humidity.

Science ◽  
2017 ◽  
Vol 356 (6345) ◽  
pp. 1376-1379 ◽  
Author(s):  
Woon Seok Yang ◽  
Byung-Wook Park ◽  
Eui Hyuk Jung ◽  
Nam Joong Jeon ◽  
Young Chan Kim ◽  
...  

The formation of a dense and uniform thin layer on the substrates is crucial for the fabrication of high-performance perovskite solar cells (PSCs) containing formamidinium with multiple cations and mixed halide anions. The concentration of defect states, which reduce a cell’s performance by decreasing the open-circuit voltage and short-circuit current density, needs to be as low as possible. We show that the introduction of additional iodide ions into the organic cation solution, which are used to form the perovskite layers through an intramolecular exchanging process, decreases the concentration of deep-level defects. The defect-engineered thin perovskite layers enable the fabrication of PSCs with a certified power conversion efficiency of 22.1% in small cells and 19.7% in 1-square-centimeter cells.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Takeo Oku ◽  
Junya Nomura ◽  
Atsushi Suzuki ◽  
Hiroki Tanaka ◽  
Sakiko Fukunishi ◽  
...  

Effects of polysilane additions on CH3NH3PbI3 perovskite solar cells were investigated. Photovoltaic cells were fabricated by a spin-coating method using perovskite precursor solutions with polymethyl phenylsilane, polyphenylsilane, or decaphenyl cyclopentasilane (DPPS), and the microstructures were examined by X-ray diffraction and optical microscopy. Open-circuit voltages were increased by introducing these polysilanes, and short-circuit current density was increased by the DPPS addition, which resulted in the improvement of the photoconversion efficiencies to 10.46%. The incident photon-to-current conversion efficiencies were also increased in the range of 400~750 nm. Microstructure analysis indicated the formation of a dense interfacial structure by grain growth and increase of surface coverage of the perovskite layer with DPPS, and the formation of PbI2 was suppressed, leading to the improvement of photovoltaic properties.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5060
Author(s):  
Jin-Myung Choi ◽  
Hiroki Suko ◽  
Kyusun Kim ◽  
Jiye Han ◽  
Sangsu Lee ◽  
...  

Perovskite solar cells (PSCs) are regarded as the next-generation thin-film energy harvester, owing to their high performance. However, there is a lack of studies on their encapsulation technology, which is critical for resolving their shortcomings, such as their degradation by oxygen and moisture. It is determined that the moisture intrusion and the heat trapped within the encapsulating cover glass of PSCs influenced the operating stability of the devices. Therefore, we improved the moisture and oxygen barrier ability and heat releasing capability in the passivation of PSCs by adding multi-walled carbon nanotubes to the epoxy resin used for encapsulation. The 0.5 wt% of carbon nanotube-added resin-based encapsulated PSCs exhibited a more stable operation with a ca. 30% efficiency decrease compared to the ca. 63% decrease in the reference devices over one week under continuous operation. Specifically, the short-circuit current density and the fill factor, which are affected by moisture and oxygen-driven degradation, as well as the open-circuit voltage, which is affected by thermal damage, were higher for the multi-walled carbon nanotube-added encapsulated devices than the control devices, after the stability test.


2021 ◽  
Author(s):  
Yuanyuan Jiang ◽  
Xiaozhang Zhu

With the development of the non-fullerene acceptor (NFA), the use of ternary organic photovoltaic devices based on a fullerene acceptor and a NFA is now widespread, and the merits of both acceptor types can be fully utilized. However, the effective approach of enhancing device performance is adjusting the charge dynamics and the thin-film morphology of the active layer via introducing the second acceptor, which would significantly impact the open-circuit voltage, the short-circuit current, and the fill factor, thus strongly affecting device efficiency. The functions of the second acceptor in a ternary organic solar cell with a fullerene acceptor and a NFA are summarized here. These include a broader absorption spectrum; formation of a cascade energy level or energy transfer; modified thin-film morphology including phase separation, effects on crystallinity, size, and purity of domain; and vertical distribution along with improved charge dynamics like exciton dissociation and charge transport, collection, and recombination. Then, we discuss the hierarchical morphology in ternary solar cells may benefit device performance and the outlook of the ternary device.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3295
Author(s):  
Andrzej Sławek ◽  
Zbigniew Starowicz ◽  
Marek Lipiński

In recent years, lead halide perovskites have attracted considerable attention from the scientific community due to their exceptional properties and fast-growing enhancement for solar energy harvesting efficiency. One of the fundamental aspects of the architecture of perovskite-based solar cells (PSCs) is the electron transport layer (ETL), which also acts as a barrier for holes. In this work, the influence of compact TiO2 ETL on the performance of planar heterojunction solar cells based on CH3NH3PbI3 perovskite was investigated. ETLs were deposited on fluorine-doped tin oxide (FTO) substrates from a titanium diisopropoxide bis(acetylacetonate) precursor solution using the spin-coating method with changing precursor concentration and centrifugation speed. It was found that the thickness and continuity of ETLs, investigated between 0 and 124 nm, strongly affect the photovoltaic performance of PSCs, in particular short-circuit current density (JSC). Optical and topographic properties of the compact TiO2 layers were investigated as well.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1684
Author(s):  
Alessandro Romeo ◽  
Elisa Artegiani

CdTe is a very robust and chemically stable material and for this reason its related solar cell thin film photovoltaic technology is now the only thin film technology in the first 10 top producers in the world. CdTe has an optimum band gap for the Schockley-Queisser limit and could deliver very high efficiencies as single junction device of more than 32%, with an open circuit voltage of 1 V and a short circuit current density exceeding 30 mA/cm2. CdTe solar cells were introduced at the beginning of the 70s and they have been studied and implemented particularly in the last 30 years. The strong improvement in efficiency in the last 5 years was obtained by a new redesign of the CdTe solar cell device reaching a single solar cell efficiency of 22.1% and a module efficiency of 19%. In this paper we describe the fabrication process following the history of the solar cell as it was developed in the early years up to the latest development and changes. Moreover the paper also presents future possible alternative absorbers and discusses the only apparently controversial environmental impacts of this fantastic technology.


2018 ◽  
Vol 9 ◽  
pp. 1802-1808 ◽  
Author(s):  
Katherine Atamanuk ◽  
Justin Luria ◽  
Bryan D Huey

The nanoscale optoelectronic properties of materials can be especially important for polycrystalline photovoltaics including many sensor and solar cell designs. For thin film solar cells such as CdTe, the open-circuit voltage and short-circuit current are especially critical performance indicators, often varying between and even within individual grains. A new method for directly mapping the open-circuit voltage leverages photo-conducting AFM, along with an additional proportional-integral-derivative feedback loop configured to maintain open-circuit conditions while scanning. Alternating with short-circuit current mapping efficiently provides complementary insight into the highly microstructurally sensitive local and ensemble photovoltaic performance. Furthermore, direct open-circuit voltage mapping is compatible with tomographic AFM, which additionally leverages gradual nanoscale milling by the AFM probe essentially for serial sectioning. The two-dimensional and three-dimensional results for CdTe solar cells during in situ illumination reveal local to mesoscale contributions to PV performance based on the order of magnitude variations in photovoltaic properties with distinct grains, at grain boundaries, and for sub-granular planar defects.


2021 ◽  
Vol 34 (1) ◽  
pp. 01-08
Author(s):  
B GopalKrishna ◽  
Sanjay Tiwari

Perovskite solar cells are emerging photovoltaic devices with PCE of above 25%. Perovskite are suitable light absorber materials in solar cells with excellent properties like appropriate band gap energy, long carrier lifetime and diffusion length, and high extinction coefficient. Simulation study is an important technique to understand working mechanisms of perovskites solar cells. The study would help develop efficient, stable PSCs experimentally. In this study, modeling of perovskite solar cell was carried out through Setfos software. The optimization of different parameters of layer structure of solar cell would help to achieve maximum light absorption in the perovskite layer of solar cell. Simulation study is based drift-diffusion model to study the different parameters of perovskite solar cell. Hysteresis is one of the factors in the perovskite solar cell which may influence the device performance. The measurement of abnormal hysteresis can be done by current-voltage curve during backward scan during simulation study. In backward scan, the measurement starts from biasing voltage higher than open circuit voltage and sweep to voltage below zero. The numerical simulation used to study the various parameters like open circuit voltage, short circuit current, fill factor, power conversion efficiency and hysteresis. The simulation results would help to understand the photophysics of solar cell physics which would help to fabricate highly efficient and stable perovskite solar cells experimentally.


Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1263 ◽  
Author(s):  
Bao Wang ◽  
Xiangyu Zhu ◽  
Shuhan Li ◽  
Mengwei Chen ◽  
Nan Liu ◽  
...  

Au@Pt@Au core-shell nanoparticles, synthesized through chemical reduction, are utilized to improve the photoelectric performance of perovskite solar cells (PSCs) in which carbon films are used as the counter electrode, and the hole-transporting layer is not used. After a series of experiments, these Au@Pt@Au core-shell nanoparticles are optimized and demonstrate outstanding optical and electrical properties due to their local surface plasmon resonance and scattering effects. PSC devices containing 1 wt.% Au@Pt@Au core-shell nanoparticles have the highest efficiency; this is attributable to their significant light trapping and utilization capabilities, which are the result of the distinctive structure of the nanoparticles. The power conversion efficiency of PSCs, with an optimal content of plasmonic nanoparticles (1 wt.%), increased 8.1%, compared to normal PSCs, which was from 12.4% to 13.4%; their short-circuit current density also increased by 5.4%, from 20.5 mA·cm−2 to 21.6 mA·cm−2. The open-circuit voltages remaining are essentially unchanged. When the number of Au@Pt@Au core-shell nanoparticles in the mesoporous TiO2 layer increases, the photovoltaic parameters of the former shows a downward trend due to the recombination of electrons and holes, as well as the decrease in electron transporting pathways.


NANO ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. 1950127 ◽  
Author(s):  
Farhad Jahantigh ◽  
S. M. Bagher Ghorashi

Perovskite solar cells have recently been considered to be an auspicious candidate for the advancement of future photovoltaic research. A power conversion efficiency (PCE) as high as 22% has been reported to be reached, which can be obtained through an inexpensive and high-throughput solution process. Modeling and simulation of these cells can provide deep insights into their fundamental mechanism of performance. In this paper, two different perovskite solar cells are designed by using COMSOL Multiphysics to optimize the thickness of each layer and the overall thickness of the cell. Electric potential, electron and hole concentrations, generation rate, open-circuit voltage, short-circuit current and the output power were calculated. Finally, PCEs of 20.7% and 26.1% were predicted. Afterwards, according to the simulation results, the role of the hole transport layer (HTL) was investigated and the optimum thickness of the perovskite was measured to be 200[Formula: see text]nm for both cells. Therefore, the spin coating settings are selected so that a coating with this thickness for cell 1 is deposited. In order to compare the performance of HTM layer, solar cells with a Spiro-OMeTAD HTM and without the HTM layer in their structure were fabricated. According to the obtained photovoltaic properties, the solar cell made with Spiro-OMeTAD has a more favorable open-circuit voltage ([Formula: see text]), short-circuit current density ([Formula: see text]), fill factor (FF) and PCE compared to the cell without the HTM layer. Also, hysteresis depends strongly on the perovskite grain size, because large average grain size will lead to an increase in the grain’s contact surface area and a decrease in the density of grain boundaries. Finally, according to the results, it was concluded that, in the presence of a hole transport layer, ion transfer was better and ion accumulation was less intense, and therefore, the hysteresis decreases.


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