Perovskite solar cells (PSCs) have appeared as a promising design for next-generation thin-film photovoltaics because of their cost-efficient fabrication processes and excellent optoelectronic ...properties. However, PSCs containing a metal oxide compact layer (CL) suffer from poor long-term stability and performance. The quality of the underlying substrate strongly influences the growth of the perovskite layer. In turn, the perovskite film quality directly affects the efficiency and stability of the resultant PSCs. Thus, substrate modification with metal oxide CLs to produce highly efficient and stable PSCs has drawn attention. In this review, metal oxide-based electron transport layers (ETLs) used in PSCs and their systemic modification are reviewed. The roles of ETLs in the design and fabrication of efficient and stable PSCs are also discussed. This review will guide the further development of perovskite films with larger grains, higher crystallinity, and more homogeneous morphology, which correlate to higher stable PSC performance. The challenges and future research directions for PSCs containing compact ETLs are also described with the goal of improving their sustainability to reach new heights of clean energy production.
Display omitted
•Ionic liquids (ILs) aided-device engineering champions is widely reviewed.•The role of ILs in the production of high-quality perovskite film is discussed.•ILs can potentially improve ...the long-term stability of perovskite solar cells.•ILs represents a significant step toward reliable perovskite PV technology.
The efficiency of perovskite solar cells (PSCs) is rapidly increasing, so that their long-term operational stability has become a major focus for commercialization and market adoption. The development of novel strategies and materials to improve the stability of small and large solar modules without compromising power conversion efficiency (PCE) is an ongoing challenge. Ionic liquids (ILs) are emerging as useful additives, solvents, and charge transport materials for the preparation of highly efficient perovskite films. Perovskite crystallizes slowly in ILs to form large and uniform grains, and PSCs fabricated with high-quality perovskite films are efficient and stable. Herein we review recently developed systemic device engineering, and we discuss the impact of ILs in the production of highly efficient and stable PSCs. This review is intended to serve as a guide to develop highly crystalline perovskite films with larger grains and more homogeneous morphologies, all of which contribute to enhancing the stability of PSC performance. Recent progress in the use of ILs as solvents and additives for PSCs is a significant step toward developing reliable perovskite photovoltaic devices. Finally, we discuss challenges and future research directions for the fabrication of efficient and stable PSCs.
A facile solution process to synthesis ZnO thin films was successfully conducted in this work. Zinc acetate dihydrates were used as the main precursor, dissolved in the mixture of acetylacetone and ...ethanol whichact as solvent and precursor simultaneously. This mixture deposited by spin coating and dried under ambient atmosphere at room temperature. The reaction mechanism, structure, morphology, chemical composition and optoelectrical properties of the resulted ZnO thin film were studied. The as deposited films were annealed at 500 °C for 2 h under O2 gas flow added with H2O vapor and CO2 gas. The ZnO thin films showed a dense, homogenous morphology and high transparency. The film is an n-type semiconductor with 3.18 eV bandgap, has 1.25 × 10−19 cm3 carrier concentration, 12 cm2/Vs electron mobility and 2.42 × 10−3 Ω·cm resistivity making it suitable for application as window layer in a photovoltaic cell.
•A two-steps non-hydrazine synthesis technique was used to fabricate CZTSe thin film.•Growth of high-quality CZTSe thin film with monoethanolamine and ethanol mixture solvent was ...investigated.•Optical and electrical characterisations were conducted to confirm the high-quality CZTSe thin film.•SCAPS-1D and 3D FDTD numerical simulations were carried out to investigate the electrical effects and optics of the device.•Optimised CZTSe solar cell estimates a conversion efficiency of 18.5%.
This article reports on Cu2ZnSnSe4 (CZTSe) thin film preparation via a nonhydrazine, nonpyridine and environmentally friendly low-cost solution process method. CZTSe fabrication through a solution-based process has not yet been suitably demonstrated given the impediments to addressing the presence of selenium in solutions. In this study, we introduced a two-step CZTSe fabrication method that used monoethanolamine as the chelating agent/co-solvent and ethanol as the main solvent. Selenization was then conducted. In this process, we successfully avoided the use of hydrazine to synthesise CZTSe thin films. Material characterisations (e.g. UV–VIS–NIR, scanning electron microscopy, electron dispersive spectroscopy, X-ray diffractometry and Fourier transform infrared spectroscopy) confirmed the high quality of the deposited thin films. The deposited CZTSe thin film showed high crystallinity without carbon residues, indicating its potential application as a photovoltaic absorber. Hence, we investigated the photovoltaic parameters of the CZTSe-based solar cells on the basis of the deposited thin film’s optoelectronic properties. We utilised Solar Cell Capacitance Simulator to examine the electrical effects of CZTSe solar cells and used three-dimensional finite-difference time-domain optical simulations to investigate the optics of the solar cells. We estimated that the realistic power conversion efficiency of the CZTSe solar cells could reach 18.5% with a short-circuit current density of 30 mA/cm2.
Cu
2
ZnSnS
4
(CZTS) thin films were prepared on soda lime glass by dip coating with sulfurized Cu, Zn, Sn precursors, N
2
gas jet flattening, and annealing under an Ar+H
2
S atmosphere, which is a ...simple and inexpensive process for large-area thin-film preparation, and the influence of the Cu/(Zn+Sn) ratio on the properties of the film were investigated. Copper (II) acetate monohydrate, zinc (II) acetate dihydrate, tin (II) chloride dihydrate and thiourea dissolved in an ethanol solution were used for the preparation of the sulfurized Cu, Zn and Sn precursors as a low-cost raw materials for chemical bath deposition, and dip coating of the precursors and annealing under an Ar+H
2
S atmosphere were applied to prepare kesterite CZTS films on substrates. Sulfurization under an Ar+H
2
S atmosphere enhanced CZTS formation with no zinc oxide and adhesion on the soda lime glass. As the Cu/(Zn+Sn) ratio was increased in the film,the grain size and the film density increased whereas the band gap energy and the resistivity decreased. All films exhibited a p-type semi-conductivity with a high carrier concentration.
CuInSe2 (CISe) thin film was successfully fabricated from copper and indium salts with ethanolamine as precursors. All of these precursors were dissolved and formed complex compounds with ...ethanolamine simultaneously which deposited on soda lime glass by spin coating at 200 rpm, followed by heat treatment in the ambient atmosphere at 200oC for 120 minutes and finally selenization at 550oC using selenium pellets under Ar (95%) + H2 (5%) for 120 minutes to fabricate CISe thin film. Reaction mechanism, structure, morphology and chemical composition also reported in this work.
The insufficient stability of CH3NH3PbI3 (MAPbI3)-based perovskite solar cells (PSCs) remains a significant concern in this field of research, so a device engineering approach is required to obtain ...efficient, stable PSCs. The present work used a sequential deposition process to alternately fabricate thin MAPbI3-based perovskite and cesium iodide (CsI) layers with precise control over the CsI intercalation, producing high quality cesium containing perovskite films. The optimal CsI film thickness when applied to either the up, down or both layers of the MAPbI3 perovskite film was also assessed. Interestingly, the application of a double layer CsI layer greatly altered the perovskite morphology to produce large grain sizes, as a result of the precise intercalation of the CsI molecules into the host MAPbI3. Furthermore, PSCs made with double layer CsI intercalation exhibited power conversion efficiencies as high as 18.43%. These exceeded the values obtained from devices made with pristine MAPbI3, or with CsI intercalation on either the bottom or top of the perovskite (16.14%, 17.92% and 17.26%, respectively). A double layer CsI intercalation device was stored in the dark at relative humidities of 40–50% for more than 4000 h and retained over 83% of its initial efficiency.
Sequential deposition technique was used to alternately fabricate CH3NH3PbI3 (MAPbI3) and cesium iodide (CsI) thin layers with precise control over the CsI intercalation, producing large grain size, and high-quality cesium containing perovskite films. When the CsI double-layer intercalate into the MAPbI3 framework effectively improves the efficiency and long-term stability of the perovskite solar cells. Display omitted
•Double layer CsI intercalation greatly altered the perovskite morphology.•The optimal CsI film thickness when applied to either the up, down or double layers of the MAPbI3 film were assessed.•Double layer CsI intercalation significantly improve the long-term stability of perovskite solar cells.
PDF
